Posted in Orthognathic Surgery

Mandibular Orthognathic Surgery

Introduction

From time immemorial, man has been trying to acquire for himself an appearance that is pleasing and acceptable to the society. Facial features often form a basis for the stereotyping of personality characteristics. Correction of facial deformities has been attempted by many people over the centuries sometimes with success but often with disastrous results.

Orthognathic surgery has become a useful and acceptable treatment modality for patients with skeletal discrepancies in addition to orthodontic problems. Over the past few decades, refinements in surgical techniques and advent of sophisticated instruments have made this surgery safe, easier and predictable.

Historical developments

Hullihen was the first person to correct jaw deformity surgically in 1849, when he corrected an anterior open bite by mandibular subapical osteotomy. The most important early contribution came from Blair in the early 1900s – he described a horizontal osteotomy of the mandibular ramus through the extra-oral route for the correction of mandibular prognathism. Ernst (1932) discussed an intra-oral approach for the same procedure. Blair was the first to classify jaw deformity into five classes as : mandibular prognathism, mandibular retrognathism, alveolar mandibular protrusion, alveolar maxillary protrusion and open bite.

Berger (1897), Babcock (1909), Bruhn & Lindemann (1921), Kostecker (1931) described similar osteotomy method of Blair for correction of mandibular prognathism.

Trauner 1955 described the inverted ‘L’ osteotomy of the ramus for the correction of mandibular prognathism.

Hugo Obwegesser (1955) described the technique of intraoral sagittal split osteotomy for the correction of mandibular problems. This was modified by Dalpont in 1958, Hunsuck in 1968 and Epker in 1977.

Heinz Köle described the procedure of genioplasty 1968 and a technique to correct open bite.

Paceno (1922) published some basic principles of roentgenographic cephalometry, which was later modified and popularised by Broadbent and Holfrath (1935). Burstone et al (1978 & 1980) gave an analysis for the assessment of dentofacial deformity using cephalometric radiographs ” The cephalometric analysis for orthognathic surgery” (COGS).

The first use of bone plating was carried out by Soerensen in 1917 for fracture mandible. Bernd Spiessl 1974 was the first to use rigid fixation after sagittal split osteotomy. Use of rigid fixation to stabilise osteotomised segment was reported by Champy & associates 1976, Mischelet, Leyoness & Desus 1973, Dromer and Luhr 1981, Steinhäuser 1986 etc.  Miniaturised plates were used by Luhr 1981, Steinhäuser 1986 etc. Miniaturised plates by Luhr, 1989 solved the problem of excessive bulk of miniplates for use in midface.

Other contributors were Bruhn, Asher, Perthes (Extra oral vertical osteotomy for mandibular ramus), Picher, Wassmund, Wunderer, (Mandibular osteotomy)

The latest developments in orthognathic surgery is the use of adjunct plastic surgical procedures like rhytidectomy, liposuction, lip correction and the use of the principle of distraction osteogenesis for correction of jaw deformities.

Surgical anatomy

The mandible is the skeletal component of the lower face. It is a single bone with four anatomically distinct regions :- a body, alveolar process, ramus and condyloid process.

The horizontal U-shaped body has

  1. a dense basilar portion that contains the neurovascular bundle and provides for muscle attachments, and
  2. an alveolar portion that is hollowed out by the teeth and is dependent on them for its development and maintenance.

The anterior midline portion of the mandibular body is termed the symphysis. It gives attachment an anchorage to the tongue muscles in the internal (lingual) aspect, and forms the prominence of the chin in the external aspect.

The vertical ramus is a thin, dense structure with little marrow that is entirely sheathed by masticatory muscles. Its antero-superior portion, the coronoid process, provides attachment for the temporalis muscle.

The mandibular condyle rests on the ramus on a thin neck and articulates with a portion of the temporal bone, the glenoid fossa. This temporomandibular joint further consists of a separating articular disc, a joint capsule, and a series of extra-capsular cheek ligaments.

Anatomical position of the mandibular canal

Knowledge of the position of mandibular canal as it courses through the ramus and body of the mandible is crucial in avoiding neurosensory deficits and excessive blood loss. The mandibular foramen lies at a mean distance of 8.3 mm below the tip of the lingula. The lingula is positioned 4.9mm + 3.5mm above the occlusal plane. Therefore the neurovascular bundle generally enters the mandibular foramen inferior to the mandibular occlusal plane.

The mandibular foramen is located about two-thirds of the distance from the anterior to the posterior border of the ramus. Tracing the course of the mandibular canal in relation to the inferior border reveals that it travels forward to the lowest point at the 1st molar region before gradually sloping superiorly to the level of the mental foramen.

Timing of osteotomies

The treatment of dentofacial deformities is based on a careful co-ordination of orthopaedics, orthodontics and surgery. Early treatment using functional appliances and by orthodontic teeth movements may prevent functional and psychological problems, limit he deformity, shorten treatment time, improve results and obtain stability. As a rule of thumb it is better to wait till the skeletal growth is completed before doing orthognathic surgery. There has been report in literature to support the corrective surgical measure even during the growth period, specially if there is compelling psychological need for such intervention in the patient.

Role of pre-surgical orthodontics

Many patients undergoing orthognathic surgery require a period of pre-surgical orthodontics. The goals of pre-surgical orthodontics are

  1. to eliminate dental mal-relationships which prevent surgical repositioning of fragments
  2. to achieve decompensation by undoing the natural compensating tooth alignments. This usually worsens the occlusal relationship but it corrected by surgery.
  3. to create interdental spacing to facilitate segmental osteotomy and
  4. to perform those tooth movements which, if done post-surgically, will spoil the result of surgery.

Surgical approach

When considering the surgical approach to the facial bones, there are a number of important aspects, some of which are mutually antagonistic. They are briefly described as

  1. there must be a safe approach which allows a clear view to be obtained of the bone to be cut and good access to instruments.
  2. the access incision and dissection should avoid important structures like nerves, large blood vessels and teeth.
  3. the incision should be placed in such a way that the scars are relatively well-hidden, if it is not possible to avoid them altogether.
  4. the approach should take into consideration the risk of sterility and post-operative infection.
  5. specific situations like trismus should be taken into account.

Extra-oral approach

The best access to the bones of the face is through the skin. However, this direct approach may lead to visible scars. So the incision should be sited in such a way that the scars are hidden e.g. in submandibular region or in the hairline.

The condylar region

The easiest approach to the mandibular condyle is through a pre-auricular incision. The pre-auricular incision is sited just anterior to the pinna or alternatively around the tragus and at the junction of ear and scalp superiorly. It is then directed obliquely forwards and upwards at a 45° angle. The external auditory meatus is occluded with cotton wool or an antiseptic dressing. After marking out the incision line and infiltrating the area with 1:2,00,000 adrenaline solution subcutaneously, the incision is made through the skin, which is then undermined and sutured forward to the cheek. The posterior branch of the superficial temporal artery is ligated. The anterior superficial temporal vessels and the auriculotemporal nerve are identified and retracted anteriorly. Next, the incision is deepened down to the temporalis fascia and the zygomatic bone, and is then extended inferiorly in the plane between the cartilaginous external auditory meatus and the back of the condyle. Anteriorly, the dissection proceeds deep to the parotid gland until the underlying condyle can be palpated. A ‘T’ shaped incision may be made over the lateral surface of the capsule to expose the condyle.

Al Kayat and Bramley in 1979 described a question-mark shaped incision which avoided the main vessels and nerves. This technique has the added advantage of a wider exposure. After dissection down to the temporal fascia superiorly, the point where the fascia splits into two layers is identified about 2 cm above the zygomatic arch. An incision is made starting at the root of the arch, running at 45°upwards and forwards through the superficial layer of the temporalis fascia. The periosteum of the malar arch is incised and turned forward as a flap, which includes within it the temporal branches of the facial nerve.

If both condyles need to be exposed, the bicoronal flap may be used. This flap has an added advantage that calvarial bone grafts may be harvested through the same approach.

The inferior end of the skin incision should never be extended below the lobe of the ear. This is to minimise the risk of damage to the main branch of facial nerve. While operating on the condyle, a Toller retractor or a Dautery retractor may be placed under the neck of the condyle to prevent injuring the maxillary vessels.

The mandibular ramus

The indications for an extra-oral route of access to the mandibular ramus include severe trismus and severe prognathism that requires large movements. The incision options include

  1. the posterior mandibular vertical incision,
  2. the Risdon incision (submandibular incision one finger breadth below the lower border of the mandible),
  3. skin crease incisions.

After marking and infiltrating the area with adrenaline solution, the skin is incised and undermined subcutaneously to expose the platysma, which is split in the line of its fibres. The investing layer of deep cervical fascia is now seen. Structures like facial vessels, marginal mandibular nerve and submandibular lymph nodes should be preserved as far as possible. By blunt dissection through the connective tissues, the lower border of the mandible is reached. The periosteum of the lower border is excised and reflected to expose the entire ramus. The masseter is then stripped off the lateral surface and medial pterygoid off the medial surface. With appropriate retraction, the whole of the ramus and the coronoid and condylar processes are all exposed.

Mandibular body and symphysis

The extra-oral approach is now rarely used to access the mandibular body and symphysis. An incision along a skin crease may be considered in cases where major repositioning of lower border is required or when access to the mouth is poor. In the body region, this is performed 1 cm below the lower border and parallel to it. The incision in symphyseal region should be in the submental crease, or 5mm below and posterior to the lower border if there is no crease. Exposure is performed in the same way as for the ramus.

Intra-oral approach

The obvious advantage of no visible scars has encouraged the development of intra-oral approach to the mandible. The visibility and instrumentation through this approach have been made easier by recent improvements in instrument design.

The mandibular ramus

The intra-oral approach for mandibular ramus is most commonly used for performing sagittal split osteotomies. Local anaesthetic with adrenaline is infiltrated in the lingual side of the ramus and in the molar region buccally before putting the incision. The incision may be placed in various ways. The easiest method is to extend the Ward’s incision for third molar surgery anteriorly along the crest of the alveolus and posteriorly up the anterior border of the ramus. Postero-superiorly, it is taken slightly on to the buccal side of the ramus. Subperiosteal dissection is carried out inferolaterally in the body area and posteriorly towards the antegonial notch. On the lingual side of the ramus, the dissection is carried towards the posterior border of the ramus. The inferior dental neurovascular bundle is identified as it enters the bone at the lingula. A little dissection anterior and lingual to the lingula is also required.

The approach for vertical subsigmoid osteotomy or subcondylar osteotomy is by a vertical incision along the anterior border of the ramus and then forward along the external oblique ridge. The periosteum along the lateral surface of the ramus is raised down to the lower border and upwards to the sigmoid notch. Specialised retractors like the Bauer or Le Vasseur Merrill type may be used to obtain adequate visibility and to aid in instrumentation.

Mandibular body

The intra-oral approach for mandibular body is used for body osteotomy of the mandible. This requires bilateral osteotomies at some part of the mandibular body, most often in the premolar region. Since 1st or 2nd premolar teeth are removed, the incision starts at the unattached gingivae opposite the first or second molar tooth, and is continued to the gingival margin just posterior to the papilla of the tooth to be extracted. It is extended around the gingival margin, and continued inferiorly and obliquely forwards towards the base of the buccolabial sulcus. Care should be taken to avoid the mental foramen and the mental nerve. The mucoperiosteal flap is then dissected back widely to the lower border. A lingual mucoperiosteal flap is raised via a gingival margin incision.

If the body osteotomy is being done to close an edentulous space, the incision may be placed over the ridge and flaps retracted buccally and lingually. A modification is to split the ridge mucosa at right angles. In non-extraction cases, the incision may be placed in the buccal sulcus, leaving attached gingiva intact.

Anterior mandible

The incision is commenced at the premolar area on one side at the junction of the attached and the unattached gingivae. It is then brought on to the lip in the canine region. A transverse incision just through the mucosa is continued round to the canine on the opposite side. A mucosal flap is raised initially on the lip, and when the mentalis muscle is reached, this is sectioned down to bone and the mucoperiosteal flap is raised from the alveolus. The anterior portion of the mandible is stripped of periosteum down to the lower border. The dissection is then extended posteriorly, inferior to the mental nerves to allow for extension of the bony cut into the molar region. Anteriorly, the lower genial muscles are left attached to the bone, thus maintaining the blood supply of the lower border fragments.


Osteotomy techniques

The surgical treatment of the deformities of the mandible must be considered in all the three dimensions. A number of osteotomy techniques are now available to correct different types of lower jaw deformities. According to the site of operation, the techniques may be divided into

  1. Ramus osteotomies
  2. Osteotomies of the mandibular body and symphysis
  3. Segmental procedures and

Ramus osteotomies

Osteotomies of the mandibular ramus are used to advance the retrognathic mandible and to retrude the prognathic mandible. They are usually the best procedures in situations where large movements are necessary. Previously done exclusively as extra-oral procedures, they are being increasingly performed through the intra-oral approach now, thanks to recent developments like oscillating saws, fibre-optic lighting systems and specialised retractors.

Condylectomy

Condylectomy is employed in the correction of only a few conditions such as ankylosis, tumours of the condyle and condylar hyperplasia. In ankylosis, removal of a condyle fused to the skull is the first step in its correction, this is followed by a reconstruction of the joint and finally by osteotomies to correct the mandibular retrusion or asymmetry.

The management of condylar hyperplasia depends on the age of the patient. Where active growth is still continuing in the condyle, a condylectomy is necessary. In many patients, the condylar overgrowth ceases towards the end of the growth period, leaving an apparent prognathic and asymmetric deformity. In such cases, the condyle may be left intact and an osteotomy performed on the affected side.

After exposure of the joint capsule by pre-auricular approach, a ‘T’ shaped incision is made on its lateral surface. The horizontal bar of the ‘T’ is placed over the maximum bulbosity of the condyle. A Toller condylar retractor is inserted posterior to the condylar neck and is then brought forward within the capsule medial to the condylar neck. This is to stabilise the condyle and to safe retraction. The bone for removal, as determine by the pre-operative assessment, is marked out with the use of callipers. A simple horizontal section is then made through the neck of the condyle onto the retractor. The deeper portion of the neck may be separated with a chisel after the bone has almost been sectioned through with a bur. After mobilisation of the condyle, it is drawn out of the joint cavity and the lateral pterygoid muscle is stripped off. If the condyle is very deformed or difficult to remove, a bur hole through its lower end and a wire inserted through it will allow traction to be applied to it, and will aid in mobilisation. Any sharp edges of bone in the distal fragment are smoothed. It there has been significant bleeding during the operation, a suction drain is inserted. Closure is done in layers.

When further orthognathic surgery is planned for the correction of residual deformities, it is better postponed for about 3 to 9 months.

Oblique subcondylar condylotomy

The descriptions of subcondylar osteotomies by Jaboulay and Berard (1898) and Kostecka (1931) are among the earliest ones for the correction of mandibular deformities. Access may be gained through a pre-auricular approach. The condylar neck is sectioned obliquely and is mandible is repositioned posteriorly. Simple overlapping of the segments is enough to facilitate bony union. Robinson (1956,1958) described the use of a nasal saw for the osteotomy while Hinds (1958) used no.8 round burs to create grooves and then completed the osteotomy using an osteotome.

The procedure done in most centres now is the one described by Ward (1961) and McKenzie (1961). This ‘blind’ approach has inherent risks of damage to facial nerve and unpredictable haemorrhage from the maxillary vessels. Under general anaesthesia, the mouth is propped wide open, and a line is drawn from a point approximately 1 cm below the ear lobe to the middle of the infra-orbital margin. A Kostecka awl is passed through the skin from the posterior border of the ramus along this line, keeping its tip in close contact with the medial surface of the ramus. It comes out through the skin at the sigmoid notch. A Gigli saw is then passed around the condylar neck using the awl as the guide. The condylar neck is sectioned maintaining an obtuse angle with the saw. Following section of both sides, the mandible is repositioned and intermaxillary fixation is applied up to 6 weeks.

The intra-oral subcondylar osteotomy is a more difficult procedure. It was first described by Winstanley in 1968. Hebert, Kent and Hinds (1970) used a Stryker oscillating saw which allowed for greater visibility. Refinements in technique were described by Massey (1974) and Walker (1977). The bone cut is most easily done with an oscillating saw. Good retraction in the condylar region is necessary by using Obwegeser retractors or Bauer’s retractors. When repositioning the distal fragment, one should make sure that the condylar head remains in the fossa and that the neck fragment overlaps the ramus on its lateral surface.

The vertical subsigmoid osteotomy

Whereas the subcondylar osteotomy may be used only in cases of mild degrees of prognathism, the vertical osteotomy of the ramus is useful in cases where large movements are required. Originally described by Caldwell and Letterman in 1954, this procedure consists of a vertical sectioning of the mandible in a line from the lower aspect of the sigmoid notch downward just posterior to the mandibular foramen to the lower border of the mandible. By decortication of the distal segment, the whole body of the mandible can be repositioned posteriorly to a more normal occlusal and jaw relation.

The chief indications include excessive mandibular prognathism and cases of facial asymmetry where large rotational move of one or more rami is required to achieve correction. This surgery has also been used to treat significant temporomandibular joint complaints, minor anterior open bite and mild degrees of mandibular retrusion.

The chief contra-indication to the vertical subsigmoid osteotomy is significant retrognathism of the lower jaw. Even moderate advancement of the distal segment have been found to cause problems like non-union and TMJ disturbances. This should be considered when facial asymmetry is treated, since advancement on side might occur inadvertently. Recent condylar fracture is another relative contra-indication.

Surgical technique

The procedure may be done through extra-oral or intra-oral approaches. Using the extra-oral approach, a skin crease / submandibular incision is made and the lower border of the mandible is exposed. The whole of the lateral surface of the ramus is then stripped of periosteum and of the attachments of the masseter. Using the Rayne subsigmoid retractor or Thompson ramus retractor, it is then possible to visualise the entire lateral surface of the ramus. The medial pterygoid insertion is reflected off the deep surface. A small bony thickening on the lateral surface of the ramus (antelingula) acts as a guide to the position of the lingula. Using an oscillating saw or a Lindemann or an Ash surgical fissure bur, a vertical bony cut is made a few millimetres posterior to the antelingula from the sigmoid notch down to a point 3 to 4 mms anterior to the posterior border of the mandible. It is better to divide the bone in a slightly oblique angle anteroposteriorly. The mandible is very thin in the sigmoid notch area and relatively thick at the lower border. When the bur / saw meets no resistance, penetration through the medial surface has been achieved. The sectioning is then completed with sharp chisel and mallet.

When the cut has been completed on both sides, the mandible is retropositioned and intermaxillary fixation is applied. Sometimes a small wedge of bone needs to be cut out of the sigmoid notch area to allow the condylar fragment to lie flush against the rest of the ramus. An interosseous wiring may be done to stabilise the position and to maintain good bony contact.

Where a greater movement is planned, a coronoidectomy or coronoidotomy is usually necessary. This may be done with a bur by sectioning obliquely from the anterior border of the mandibular ramus to the sigmoid notch. This makes it easier to position the mandible posteriorly by preventing development of excessive tension in the temporalis muscle. Decortication of the lateral surface is another procedure done to facilitate large movements.

One or two loose sutures are used to reconstitute the periosteal and muscle sling at the lower border.  A drain may be inserted if there is excessive bleeding. Simple suturing of muscle, deep fascia, platysma and skin are done in steps.

This method has two main disadvantages – it leaves an external scar, and there is risk of damage to the mandibular branch of facial nerve. Recent improvements in visibility and instrumentation in the ramus area have led to the use of intra-oral approach. The mandibular ramus is exposed via a straight-line incision medial to the external oblique ridge, or alternatively via an extended third molar incision. Following a complete subperiosteal dissection of the lateral surface of the ramus and the body s far forward as the distal aspect of the first molar, retractors can be inserted in the lateral side of the ramus. Some stripping of muscle on the medial side and identification of the inferior alveolar bundle may be helpful. With the mandible in closed position, the osteotomy cut is performed with the oscillating saw angled at 120° in a slightly curved fashion. The cut is made from posterior to the mandibular foramen up to the sigmoid notch and down to the antegonial notch. Where major posterior positioning of the ramus is required, a coronoidectomy is often necessary. This may be done through the same incision line after exposure of the lingual side.

Bell et al (1980) recommended that medial pterygoid muscles should not be stripped off to keep the condylar stump in a good position. However, Epker and Wolford (1980) felt that this approach is more likely to lead to relapse. They advocated wiring the proximal fragment to ensure that the condyle is seated in its fossa. Mucoperiosteal flaps are closed in the usual way after intermaxillary fixation.

Horizontal ramus osteotomy

The horizontal osteotomy of the mandibular ramus was first proposed by Blair in 1907. His technique consisted of passing a Blair needle or a Gigli saw through a short skin incision at the posterior border of the ramus, introducing the saw to the medial surface of the ramus and making a section. Numerous complications like injury to the facial nerve, maxillary artery bleed, inferior alveolar nerve damage, parotid gland injury and relapse have been attributed to this technique by various authors.

The original technique was modified by many surgeons till sagittal split was introduced in 1950s. One of the first modifications was the blind Gigli saw procedure, offered by Hensel in 1937. Moose in 1945 proposed an intra-oral direct visualisation osteotomy, done with an orthopaedic power-driven saw. He also endorsed a handsaw suggested by Sloan in 1951. In 1941, Kazanjian advocated horizontal osteotomy above the mandibular foramen by the Risdon approach and used a surgical bur for the bony cut. In 1951, he recommended an incision through the bone at an angle using a sharp osteotome. He believed that ‘bevelling in this fashion allowed for greater area of contact of the cut ends, promoting early consolidation’. This may have been the initial conception of the Obwegeser-Dalpont sagittal splitting procedure.

The disadvantages of horizontal ramus osteotomies include

  1. a tendency to produce open bite anteriorly by the power of masticatory muscles and the counter-action of depressor muscles
  2. non-union produced by minimal bone apposition and
  3. requirement of long periods of immobilisation.

The sagittal split and its modifications

The bilateral sagittal split osteotomy (BSSO) is an indispensable surgical procedure for the correction of lower jaw deformities. It is a highly versatile technique that allows for mandibular repositioning over large distances in many directions. The indications are many and include horizontal mandibular excess, deficiency and asymmetry. It is the operation of choice for mandibular advancement. The BSSO is very useful for mandibular setback of small to moderate magnitude.

History

A surgical procedure resembling the sagittal split was described in 1942 in the German literature by Schuchardt. Trauner and Obwegeser (1957) described a horizontal osteotomy of the mandibular ramus made through the medial cortex, just superior to the mandibular foramen, followed by a vertical cut taken down the anterior border of the ramus, and an oblique cut made through the lateral cortex towards the angle of the jaw. Though very satisfactory for mandibular excess, there was relatively little bone contact in mandibular retrusion. Dalpont (1961) suggested that this problem could be overcome by advancing the oblique cut towards the molar region, and making it vertical through the lateral cortex. Hunsuck (1968), modified the technique, advocating a shorter, horizontal medial cut, just past the lingula, to minimise soft tissue dissection, while maintaining the anterior vertical cut. In 1977, Epker suggested several modifications, including minimal stripping of masseter. Bell and Schendel (1977) established the biologic basis of BSSO and showed that with minimal detachment of the pterygomasseteric sling, complications could be reduced. Several other modifications have come up over the years, but the basic technique remains the same.

Surgical technique (Epker modification of Obwegeser-Dalpont technique)

The BSSO is usually done as an intra-oral procedure. After the injection of a vasoconstrictor in to the soft tissues of the third molar both lingually and buccally, an incision is made just lateral to the crest of the alveolus. Alternatively, an extended Ward’s incision may be used. The incision is extended up the anterior border of the ramus and anteriorly along the external oblique ridge. The incision is carried as far anterior s the surgeon has planned to make the anterior vertical cut through the lateral cortex, usually as far as the 2nd or 1st molar tooth. A subperiosteal dissection is done laterally over the body of the mandible down to and under the lower border. On the lingual side of the ramus, the subperiosteal dissection is extended up to the posterior border, identifying the lingula and the neurovascular bundle in the process. The anterior dissection is carried forward over the internal oblique ridge. An Obwegeser channel retractor or a similar instrument may be used to expose the lower border. Exposure of the coronoid process by stripping of the temporalis muscle may be necessary.

A retractor is inserted medially to prevent damage to the neurovascular bundle. The lingual cortex is then divided from just posterior to the lingula to the anterior border of the ramus using an Ash fissure bur. This bur cut is extended down along the anterior border of the ascending ramus just medial to the external oblique ridge. When the anterior limit of the bone cut has been reached, it is then taken downwards through the lateral cortex to the lower border. It must be ensured that the cortex is completely cut through, but not so deeply that the neurovascular bundle is injured. The anterior vertical cut is then extended right through the lower border with burs and fine chisels.

The lateral-lower border fragment may be split from the medial portion with a fine chisel, which can be used to separate the two fragments. The chisel is moved along the entire bony cut including the ramus section, keeping it in close contact with the lateral fragment. Gentle levering is done to separate the two cortical plates. As they separate, attention should be paid to the neurovascular bundle which should lie in the medial segment. If it lies in the lateral segment, it will need to be separated from that cortex. In mandibular setbacks for prognathism, a portion of the lateral cortex of bone will need to be removed, and the medial pterygoid must be stripped off to allow posterior positioning.

After both the sides have been similarly split, it should be possible to place the body of the mandible in the new desired position. In order to prevent relapse, it should be made sure that there is no rotational movement of the proximal segment. Some minor trimming of the fragments may required to obtain flush contact. An inter-osseous wire is placed at the upper border or at the anterior end of the ramus to hold the bone ends in the correct position. Then the final tightening and positioning of the wires is done with the teeth in the new relationship to ensure a passive repositioning of the fragments. The incision is closed either with black silk or with a resorbable suture. With the fixation in place, it would take at least 6 weeks to obtain adequate healing.

Eventhough it is a very versatile method, the BSSO has some limitations. When an open bite is present, there is a tendency to relapse. Also, in cases of mandibular retrusion where the ramus height is short, it is of little value.

Inverted ‘L’ and ‘C’ osteotomies

Originally described by Trauner and Obwegeser in 1957 as an intra-oral procedure, the inverted ‘L’ osteotomy is a blend of the vertical subsigmoid ostyeotomy and the BSSO techniques. It can also be accomplished through the submandibular approach. It is a safe and relatively simple operation for the treatment of severe mandibular retrusion. It allows for lengthening of the ramus, for which a bone graft is required to fill the defect. For large (>12 mm) advancements, concern over adequate bony interface between the segments and the concomitant problem of stability after BSSO are eliminated. For large mandibular setbacks, it bypasses the need for coronoidectomy. There is also less risk of condylar sag when compared to the vertical subsigmoid osteotomy. This procedure is well suited for secondary correction of proximal segment malrotation following BSSO, as well as for simultaneous advancement and lengthening of ramus in cases of severe ramus underdevelopment.

The extra-oral technique is similar to that used for the vertical subsigmoid osteotomy. A vertical bony cut is made downwards from a point just a few mms above and behind the lingula. The horizontal cut is made from the upper extremity of the vertical cut in a forward direction to end in the anterior border of the ramus. This may be done with either a bur or a saw. Extensive stripping of temporalis muscle is unnecessary. Bone grafts should be carefully shaped to fit the defect created following the application of intermaxillary fixation. Usually, the grafts are harvested from the iliac crest and are held in place with rigid fixation. Where the technique is used for treating mandibular prognathism, the proximal fragment should be trimmed back to allow for posterior positioning. Often the inferior end of the fragment will need to be removed.

The intra-oral technique is similar to BSSO in the initial incision and dissection. After identification of the lingula and the neurovascular bundle, the bicortical horizontal osteotomy is done just superior to, but as close as possible to the foramen. This is done with either a reciprocating saw or a Lindemann bur. The cut should stop a few millimetres posterior to the lingula. Exposure of the lateral ramus and the vertical cut are similar to the intra-oral vertical subsigmoid osteotomy, except that the bicortical vertical cut ends just superior to the level of the lingula.

In cases where extensive movement is required, the soft tissue tension limits mobilisation. Extensive stripping of soft tissue from the distal segment, scoring of the periosteum, division of the temporalis tendon and release of suprahyoid musculature may be necessary to achieve passive mobilisation. The placement of bone grafts is much more difficult in the intra-oral technique.

The ‘C’ osteotomy is basically a modification of the inverted ‘L’ osteotomy.  Instead of bringing the vertical subsigmoid ‘cut’ down to the lower border, it is brought forwards, below the level of the mandibular canal, in a horizontal direction. It is completed by making a short vertical cut anteriorly through the lower border. This method allows the mandible to be advanced, often without the need for bone grafting, but produces a defect in the ramus.

The arcing ramus osteotomy described by Epker and Wolford in 1980 is similar to the ‘C’ osteotomy. In this technique, the inferior alveolar nerve is preserved by cutting a window in the region of the lingula and following the nerve through in its canal in the anterior direction. The bony cuts follow a smooth arc rather than a simple joining of vertical and horizontal cuts. The use of ‘C’ or arcing osteotomy allows the mandible to be advanced in cases of steep mandibular plane angle, while leaving the pterygoid muscles totally attached to the proximal segment.

Mandibular body osteotomies

The mandibular body osteotomy was first described by Blair in 1907 as an extra-oral procedure. In 1912, Harsha corrected prognathism by excising a rhomboid shaped bone from the 3rd molar area using ‘bone-cutting forceps and rongeurs’. New and Erich (1941) favoured ostectomy in the bicuspid or the 1st molar regions, and preferred an open (combined extra-oral and intra-oral) approach. In 1944, Dingman described a two-stage method of ostectomy in which he overcame the disadvantage of compounding the extra-oral wound intra-orally, and also avoided injury to the mandibular nerve. This operation was widely used in 1940s and early 1950s. Thoma (1969) recommended intra-oral osteotomy using bone drills and osteotomes.

Now, almost all cases of mandibular prognathism are treated with ramus osteotomies. The present indications of body osteotomy are

  1. to utilise space from planned extraction sites or already missing teeth,
  2. in gross mandibular prognathism in combination with a ramus procedure,
  • in prognathic cases where the body is long in relation to the ramus,
  1. anterior openbite restricted to the anterior dento-alveolar segment,
  2. transverse excess of mandible (combined with genioplasty) and
  3. surgical correction of curve of Spee.

The technique for the body osteotomy is variously performed. In mandibular prognathism, where a premolar is planned to be removed, a buccal periosteal flap is raised. The mental nerve is identified and the tooth at the osteotomy site is extracted. A small lingual flap is raised, extending this slightly posteriorly. Using a template, the bone to be removed is marked out with a thin bur. The line of the mandibular canal is marked out on the lateral cortex using burs. The area of bone immediately above the canal is cut and removed with a chisel. The outer cortex overlying the canal is then divided, a rectangular portion is removed, and the nerve and vessels identified. The lower border segment is now removed completely as a wedge from below the canal. Keeping the lingual strut intact, the other side is operated upon in a similar way. Then the neurovascular bundle is lifted away from the lingual strut, and the latter is removed using burs and chisels. A lower border or cortical wire in the midbody area is inserted on both sides, but not tightened. The mandibular segments are then repositioned with the help of previously fabricated splints, and intermaxillary fixation is applied. After this, any gap that may be present is filled with cancellous bone taken from the removed bone pieces, and the interosseous wires are tightened.

When this procedure is used to correct mandibular deficiency, it is better to use a step osteotomy, with the step directed anteriorly. It is usually possible to put a wire across two stepped portions and for the gaps to be filled in with cortico-cancellous bone grafts. The mucoperiosteal flaps should be adequately mobilised to provide for good closure of soft tissue over bone.

The step sliding osteotomy and the horizontal ‘L’ sliding osteotomy are modifications of the procedure, intended to aid in anterior positioning of the distal segment and to increase the bony interface.

The disadvantages of the procedure include high risk of mental nerve paresthesia and loss of teeth. Since the mandibular angle is not interfered with, some patients show poor post-surgical cosmetic result. Removal of a large segment of bone results in imperfect bone end apposition, or excessive medial rotation of the proximal fragments.

Segmental (subapical) procedures

Osteotomies of the mandibular ramus are the oldest procedures used to correct jaw deformities. Initially described in 1849 by Hullihen, a procedure similar to a subapical osteotomy was used to treat a case of ‘elongation of lower jaw’ secondary to a burn injury. In 1910, Babcock described an extra-oral operation to accomplish forward movement of a mandibular segment. Modifications of the intra-oral procedure were later described by Hofer (1936, 1942) and Köle (1959), who popularised this surgical option.

Before the widespread use of maxillary osteotomies, subapical osteotomy of the mandible was advocated for correction of anterior micrognathia. The subapical osteotomy avoids the detrimental forces placed on the mandible by the suprahyoid musculature since the bony cuts are placed superior to these muscle attachments.

The indications for subapical procedures include

  1. malocclusion caused by a mandibular dento-alveolar deformity with appropriately positioned maxillary and mandibular skeletal bases,
  2. non-skeletal openbite (often combined with maxillary subapical osteotomy)
  • posterior and lateral apertognathia, not amenable to orthodontic correction,
  1. as a substitute for orthodontic levelling and
  2. specific cases requiring intrusion of mandibular incisors where proclination of these teeth would be detrimental.

Anterior mandibular subapical osteotomy

The anterior subapical osteotomy can be used as a single isolated procedure, or more frequently, in conjunction with other surgical procedures. This technique can be used to effect extrusion, intrusion, uprighting or anterior or posterior positioning of the anterior mandibular dento-alveolar segment.

After infiltrating the lower labial mucosa with vasoconstrictor, the anterior mandible is approached through a bucco-labial flap. The incision extends from first bicuspid to first bicuspid, and is first carried only through the mucosa, to further dissect in an oblique fashion through the mentalis down to the periosteum. The periosteum is incised, and the anterior mandible is degloved to the inferior border. The dissection proceeds posteriorly at that level and the mental foramen and nerve are identified. Since the vitality of the osteotomised segment is predicated on the lingual mucoperiosteum, inadvertent tearing or detachment of this pedicle should be strictly avoided. Once the nerve is visualised and protected, the mucosal incision can be extended posteriorly as dictated by the proposed osteotomy site. If an extraction is planned, it can be done at this stage. The labial periosteum is elevated superiorly to the crest of the ridge to expose the osteotomy site.

The vertical osteotomy is performed with rotary instruments or appropriate microsaws. If the vertical cut is at or proximal to the mental foramen, it will be necessary to reposition and retract the mental nerve. The lingual soft tissues should be protected using a Howarth periosteal elevator during the osteotomy. The horizontal osteotomy cut is made at least 5 mm below the root apices of the teeth to prevent devitalisation. This cut joins inferior extent of the vertical cuts, and should be perpendicular to the bone surface. The remainder of the osteotomy may be completed with thin osteotome or spatula chisel.

After mobilising the segment and removing any interfering bone ends, it is repositioned to the planned post-surgical site with the help of pre-formed surgical splints. The segment is secured by trans-osseous wires, or preferably semi-rigid fixation. While closing the wound, it is important that the mentalis muscle is approximated to its original anatomic location. Following this, closure is done in at least two layers.

Posterior mandibular segmental osteotomy

The posterior subapical osteotomy is done in cases requiring intrusion of the posterior dento-alveolar segment. This procedure requires isolation of the whole length of the inferior dental nerve in relation to that segment and retention of soft tissue pedicle in the lingual aspect. To maintain the apical blood supply, at least 5mm of bone should be present below the root apices. This is a difficult procedure to perform and is mainly of only academic interest.

Total mandibular subapical osteotomy

The total mandibular subapical osteotomy was described by MacIntosh (1974) and Booth et al (1976). However, as early as in 1961, Dalpont had described a similar procedure that included an oblique retromolar osteotomy and a total or a partial sagittal osteotomy of the mandibular ramus. This procedure may be used for advancement of the whole of the lower arch where it is retroposed but the mandible is in normal shape. It could also be helpful in increasing the vertical height of the lower jaw and for levelling procedures.

When combined with a sagittal split, a horizontal subapical cut is made below the teeth and below the mandibular canal, from the third molar region on one side to the opposite side. This is then joined to a vertical cut through the lateral cortex which extends superiorly to the crest of the alveolus and then posteriorly up the ramus of the mandible as in a sagittal split osteotomy. On the ramus, it is finished just beyond the lingula. After making it sure that the horizontal division of the main body of the mandible is complete, the ramus is split as in BSSO. The segment is mobilised and repositioned as necessary using pre-fabricated splints and intermaxillary wires.

When performed alone (not combined with a ramus split), the buccal cortical bone is cut above and below the mandibular canal and the cortex removed. The horizontal osteotomy is done above the level of the canal and below the apices of the teeth, taking care not to injure the lingual soft tissues. Segmentalisation of the alveolus is completed by performing vertical osteotomies at the 3rd molar extraction site or between adjacent teeth. For setbacks, some amount of bone may need to be removed from the third molar or retromolar regions.

Genioplasties

Anatomically, chin is the area below the labiomental fold. It is one of the most prominent facial features. Chin deformities can manifest in three dimensions, but the vast majority are in the horizontal plane. The term genioplasty implies all surgical procedures performed on the bony chin. These are often used in associated with other operations of the jaws. By segmentalising the chin while maintaining the lingual pedicle, it can be moved in all three dimensions of space.

History

The horizontal sliding osteotomy of the chin was first described by Hofer (1942), who used an extra-oral approach and achieved fixation with trans-osseous wires. Converse in 1950 discussed the feasibility of bone grafts introduced through an intra-oral approach. Trauner and Obwegeser (1957) used the horizontal osteotomy through an intra-oral incision. Converse and Wood-Smith in 1964 described various applications for the horizontal osteotomy. In 1965, Reichenbach et al proposed wedge osteotomy for vertical shortening of chin. Hinds and Kent (1969) discussed the importance of maintaining the soft tissue pedicle along the inferior segment.

Surgical technique

The incision and flaps are very similar to those used for anterior segmental surgery. The periosteum is stripped off the anterior surface of the mandible and care is taken to avoid any damage to mental nerves. An extension of periosteal stripping is required below the mental foramina and back to the 1st molar region.

The bone cut is made using an Ash surgical fissure bur or an oscillating saw, 5mm below the apices of teeth. The cut is angled in such a way that the chin prominence is brought up or down in anterior or posterior slides. It is essential to leave a good lingual soft tissue pedicle. Periosteum may be stripped off the distal part of the segment, but in the midline always the geniohyoid and often the digastric muscles should be left attached to the lower border. After repositioning the segment, fixation is obtained with carefully placed inter-osseous wires, and closure is in two layers. A pressure dressing is applied to minimise chances of haematoma formation, and to facilitate soft tissue reattachment.

Horizontal advancement

The inferior segment is brought forwards and its lingual cortex is fixed with wires to the buccal cortex of the main body of the mandible. An alternative is to place suitably bent miniplates. In this procedure, the advancement is limited to the overall thickness of the symphysis. Occasionally, the chin is so deficient that a double sliding horizontal osteotomy must be used. The technique involves the creation of a stepped intermediate wafer of bone between the mandible and the inferior fragment, which is also advanced to provide bony contact between the upper and lower fragments. Alternatively, a sandwich bone graft may be used to get good interface and to ensure a predictable contour.

Horizontal setback

The proximal tips of the mobilised fragment are reduced to ensure a smooth transition along the inferior border. Also, the surgeon must be aware of the possible loss of vertical dimension of the chin.

The tenon technique

Michelet et al in 1974 described the ‘tenon’ technique of genioplasty. A ‘U’ shaped monocortical osteotomy is created centrally in the symphysis. Lateral extensions are developed below the mental nerves, which connect to the superior limbs of the ‘U’. Full thickness osteotomies are completed on the lateral extensions but only through the lingual cortex on the superior aspect of the ‘U’. The resultant full thickness of bone behind the tenon allows for better positioning and lag screw fixation. When posterior movement is desired, the ‘U’ is inverted and the tenon is in the inferior fragment.

Vertical reduction

The vertical height changes can be effected by altering the angle of the osteotomy. The magnitude of vertical dimensional change is proportional to the amount and direction of the horizontal movement. If it is desired to shorten the chin without horizontal changes, a wedge reduction is indicated, which may be performed using horizontal osteotomy or tenon technique. It is technically easier to do the wedge ostectomy from the superior stable fragment.

Vertical augmentation

This is indicated when the lower facial height is to be increased, when the deficit is in the mandibular alveolus or the symphysis. Vertical augmentation is accomplished by altering the angle of the horizontal cut or by interpositional grafting or alloplastic implant placement between the osteotomised segments.

Diagnosis-based treatment

Before embarking on attempts to correct dento-facial deformities, it is essential to have an accurate diagnosis of the existing problem. Clinical examinations, cephalometric measurements and model analysis are useful to this count. A treatment plan should be arrived at on the basis of this diagnosis and should include the osteotomy planned, amount and direction the segments are to be moved and movement of teeth using pre-surgical or post-surgical orthodontics. Often there will be a particular treatment that provides the best result, but ideally the treatment plan of each patient should be individualised as no two deformities are ever alike.

Mandibular prognathism

Before attempting correction of mandibular prognathism, it is necessary to assess whether the condition is a true mandibular excess or a case of midface retrusion. Most patients with mandibular prognathism presents with a long lower jaw, Class III malocclusion, excessive facial height and a high FM angle.

Mandibular prognathism may be corrected using a wide variety of surgical manoeuvres. Previously popular procedures included conylotomy, subcondylar osteotomy, Obwegeser sagittal split and mandibular body osteotomies. Now most patients are treated by some form of ramus osteotomy like the BSSO, vertical ramus osteotomy or inverted ‘L’ osteotomy. As required, an advancement or reduction genioplasty in horizontal or vertical dimension may be performed as an adjunctive procedure.

Mandibular retrognathism / micrognathia

The treatment of mandibular retrognathism is difficult owing to the tendency to relapse and problems with bone grafting. The BSSO and vertical ramus osteotomies are useful only for moderate cases. The inverted ‘L’ osteotomy may be a better procedure in such cases. In some cases, a long genioplasty is required to correct chin retrusion.

The problems of relapse have been solved to a good extent with rigid fixation and bone grafting. The distraction osteogenesis technique is fund to be valuable tool in the correction of mandibular retrognathism

Bimaxillary protrusion

The term bimaxillary dento-alveolar protrusion refers to a condition in which the maxilla and mandible both are so severely protruded that the lips cannot be closed without strain. The condition may or may not accompany relative protrusion of the jaws themselves. Since bimaxillary protrusion is compatible with good occlusal relationship, the patient’s problems are primarily aesthetic.

Orthodontic correction of bimaxillary protrusion can be carried out quite successfully in both growing children and non-growing adults. The main disadvantage of orthodontic correction is that due to anchorage loss, the space available cannot be used to its full extent for retraction.

In its simplest form, surgical treatment of bimaxillary protrusion involves maxillary and mandibular segmental osteotomies following extraction of first or second premolars, to retract and frequently to intrude protruding maxillary and mandibular incisors. In many instances, an adjunctive augmentation genioplasty is also required to achieve a good facial profile. Other procedures often required for the correction of severe bimaxillary protrusion are LeFort I osteotomy and mandibular body/ramus osteotomies.

Apertognathia

Apertognathia (open bite) is more of a neuromuscular rather than anatomic problem. Development of severe open bite is related to positioning of mandible relative to maxilla, and is usually associated with differential growth of different dento-alveolar segments. There are three general influences in the aetiology of open bite deformity. They are

  1. genetic
  2. sucking habits in childhood and
  3. tongue posture and positioning

Orthodontic treatment of open bite deformity is based on redirection of growth (headgear, chin cap and functional appliances), habit control and tooth movements. It is among the least successful of all orthodontic treatments.

The commonly used surgical procedures for correction of alveolar open bite are

  1. anterior maxillary subapical osteotomy for extrusion,
  2. anterior mandibular subapical osteotomy for extrusion,
  3. mandibular body V, Y or step osteotomy,
  4. bilateral sagittal split osteotomy (mild open bite),
  5. posterior maxillary osteotomy for intrusion,
  6. LeFort I osteotomy with differential superior impaction of posterior segment (combined with anterior maxillary osteotomy),
  7. combination of any of these and
  8. adjunctive procedures like inferior turbinectomy and tongue mass reduction.

Köle procedure

The Köle procedure consists of a standard anterior mandibular subapical osteotomy, following which a portion of the lower border is removed as in genioplasty. The lower border segment is stripped of all its periosteum and muscle. Its ends and edges are then trimmed and it is inserted into the gap produced by raising the anterior segment. The new lower border will need to be shaped to give a more normal outline to the chin prominence. When a genioplasty is thought to be inappropriate, a bone graft or alloplastic material may be used to fill the gap.

Facial asymmetry

Facial asymmetry is among the most difficult of all the facial deformities to treat. Accurate diagnosis of the problem and meticulous treatment planning is very important in its treatment. The mandibular procedures commonly used to correct facial asymmetry are ramus osteotomies including BSSO and lateral sliding genioplasties.

Although no face is perfectly symmetrical, minimal discrepancies are often not noticed. The common instances where a significant degree of facial asymmetry is seen are

  1. unilateral condylar hyperplasia / hypoplasia
  2. unilateral ankylosis of the temporomandibular joint
  3. hemifacial microsomia / macrosomia and
  4. unilateral masseteric hypertrophy (rare)

Condylar hyperplasia

The condylar hyperplasia typically occurs during late adolescence and is accompanied by elongation of the condylar head and neck. When it presents before the growth has ceased, there may be additional skeletal and dental compensations that also affect the upper jaw. Very often, there is a bowing of the inferior border of the mandibular body.

The management of condylar hyperplasia depends on the age at which it presents. When active growth is still continuing in the condyle, a condylectomy is necessary, but in cases where there has been a continual downgrowth of maxilla to compensate for changes in the mandible, other operations may be necessary. In many patients, this overactivity ceases after the growth period, leaving an apparent asymmetric prognathic deformity. In these cases, the condyle may be left behind, and an osteotomy performed on the affected side. Maxillary levelling procedure commonly performed is a LeFort I with differential superior impaction of affected side. For mandibular correction, a subcondylar or subsigmoid osteotomy is usually done. An inferior border corticotomy of the mandibular body on the affected side may be required. Where there has been some rotation of the chin, a lateral sliding genioplasty may be done.

TMJ ankylosis / condylar hypoplasia

The surgical correction of jaw deformities secondary to TMJ ankylosis generally follows the same principles of condylar hyperplasia correction. If ankylosis release and costochondral grafting is done at an early age, the growth of the grafted part compensate the deficiency to a good extent. If done at a later stage, the defect would already have become severe and combined maxillary and mandibular procedures with massive repositioning f the segments. An adjunctive genioplasty is often required.

Hemifacial microsomia

Hemifacial microsomia (first arch syndrome) usually presents as facial asymmetry characterised by under development of TMJ, mandibular ramus, muscles of mastication, maxillary and malar bones, parotid gland and external ear. The relative retrusion of the mandible and its asymmetric development results in a compensatory slanting of the already hypoplastic maxilla, causing a significant slanting of the occlusal cant.

The earliest treatment attempted is soft tissue replacement of the auricular tracts and sinus tracts. Surgical correction of asymmetry and malocclusion requires complete maxillary and mandibular repositioning. The maxillary surgery usually performed is LeFort I with differential superior impaction of the unaffected side. The mandibular surgeries include bilateral sagittal splits and genioplasties. Prediction tracing, model surgeries and the use of prefabricated splints are essential in this procedure. Camouflage procedures like genioplasty and augmentation of the deficient parts may also be done. Materials used for augmentation include autogenous bone and alloplastic materials.

Transverse mandibular deficiency

Transverse mandibular deficiency is commonly managed by the orthodontic correction of the resultant crowding, which may be by extractions, interproximal reduction of tooth mass and dental compensations. Surgery is often required to correct the basal bone problem. This is especially true in narrow and tapered arch forms, in complete telescopic bites (Brody’s syndrome, Pierre-Robin syndrome etc) and in those whose crowded teeth have already been treated by orthodontic therapy. These patients might benefit from surgically assisted rapid mandibular expansion.

The technique involves a vertical osteotomy in the symphyseal area and the use of a Haas expansion appliance. The appliance is placed a few days before surgery. A horizontal genioplasty cut is combined with the vertical osteotomy placed between the roots of lower anterior teeth. Once the osteotomy is completed, a guide pin is inserted into the appliance and activated. The activation is continued every 48 hours until the expansion is completed.

Transverse mandibular excess

Transverse excess of the mandible is usually seen in association with true mandibular excess (with or without prognathism). Other conditions that present for treatment include masseteric hypertrophy and bilateral condylar hyperplasia.

True mandibular excess

The transverse deformity associated with true mandibular excess has been surgically treated in various ways. Most procedures involved extraction of 1st or 2nd premolar teeth and reduction in the symphyseal / parasymphyseal areas. The options include

  1. a mandibular body ‘step’ osteotomy, in which the ostectomy in the 1st premolar region is curved forward to proceed downward anterior to the mental foramen.
  2. a connected subapical osteotomy and symphyseal reduction, which could be combined with or without ramus osteotomies like BSSO.
  • if mandibular intercanine width is greater than maxillary intercanine width, a vertical interdental osteotomy or ostectomy of the anterior part of the mandible may be done.
  1. if there is a concomitant posterior cross-bite, a differential ostectomy at the medial cortex of the symphysis allows for narrowing of mandible by medial rotation of the right and left halves, with rotation occurring in the vertical axis of the condyles. If combined with ramus osteotomies, the stress on condyles is reduced.

Masseteric hypertrophy

Masseteric hypertrophy is characterised by a combination of masseter muscle enlargement and skeletal deformity in the region of angle of the mandible. The skeletal deformity is a combination of extremely acute gonial angle, lateral flaring of the mandibular angle and a reverse slope of the ascending ramus.

The medical treatment of the condition is intramuscular injection of dilute botulinum toxin. Surgical treatment consists of reduction of muscle mass and ostectomy of mandibular angle. It is usually done as an extra-oral procedure, but using angled oscillating saws and other specialised instruments, it is now possible to do it intra-orally.

Short mandibular ramus

Short mandibular ramus deformities are characterised by a lack of posterior facial height. This is frequently associated with anterior maxillary hyperplasia and always with a posterior maxillary hypoplasia. The mandible is small and retrusive and the chin lacks anterior projection.

Surgical correction is directed to elongation of posterior facial height and increased projection of lower face. Maxillary correction is accomplished by a LeFort I osteotomy. The posterior facial height is then increased by bone grafting. At the same time, the anterior maxillary excess is resected and the anterior face height shortened. The chin deformity is corrected by a combined advancement / vertical reduction genioplasty. The actual problem in the ramus may be treated with sagittal split and advancement. Large ramus deformities need to be corrected through an extra-oral approach using a ‘V’ or inverted ‘L’ osteotomy.

Obstructive sleep apnoea

Obstructive sleep apnoea (OSA), originally described by Burwell as pickwickian syndrome, is the most common sleep related breathing disorder, with a reported incidence of 1% to 3% in industrialised countries. The incidence is higher in elderly and male population. Patients commonly present complaining of excessive daytime somnolence (EDS), insomnia, headache, loud and obnoxious snoring, decreased cognitive functioning during waking hours and physical and sexual dysfunction.

Studies have revealed that the pathology of the disorder is an anatomical and physiological obstruction in the oropharynx, specifically collapse of the lateral and posterior pharyngeal walls in most cases. This propensity towards airway collapse is increased in the presence of redundant tissues or decreased posterior airway space as a result of a retropositioned tongue base. Obstruction of the upper airway during sleep results in significant cardiopulmonary and central nervous system dysfunction. Apart from clinical examination, cephalometric radiographs and nocturnal polysomnographs are helpful in diagnosis.

The OSA patients are treated by medical or surgical therapies, but more often by a combination of the two. Medical management of OSA includes weight loss, changes in sleep position, pharmacologic options, oral appliances and continuous positive airway pressure (CPAP). Surgical options include tracheostomy, uvulo-palato-pharyngoplasty, maxillomandibular advancement and various combinations of these. Additionally, septoplasty, hyoid advancement and tongue reduction are utilised as adjunctive procedures.

For maxillomandibular advancement, models are prepared and two splints are fabricated. The first splint is a registration of the occlusion after the mandible is advanced 8 to 10mm, and the second splint is that of the final occlusion after maxillary model has been moved to centric occlusion with respect to the new mandibular position. The mandible is first advanced via BSSO and IMF is placed using the first splint as a guide. The mandible is then fixed using bicortical screws and IMF is released. Then the maxilla is advanced via a LeFort I osteotomy and IMF is applied again, this time using the second splint. Maxillary fixation is accomplished using two specially designed miniplates. Bone can be secured into the advancement gap and secured with a miniplate or lag screw. The septum is fixed to the anterior nasal spine using 2-0 Vicryl. While closing the wound, an attempt should be made to return the alar base to the pre-operative width.

The goal of maxillomandibular advancement is to maximise upper airway space and to reduce upper airway resistance. It is successful because the airway is increased at multiple levels. Advancing the maxilla pulls the soft tissues of the palate forward and upward, brings the palatoglossus forward and opens the nasal valve. Moving the mandible forward results in a more anterior position of the tongue base and a more favourable position of the hyoid.


Fixation techniques

After adequate repositioning of the segments, it is important to hold them rigidly in their new positions. Traditionally this has been achieved with intermaxillary fixation using arch bars or cast silver cap splints. Two advantages of using archbars are that they can be applied quickly and have lugs available for use during IMF. However, archbars may loosen during elastic traction or placement of IMF, leading to improper positioning of osteotomised segments. Additionally, tooth movement might occur due to non-passive adaptation of the archbar.

A better method of controlling occlusion before, during and after orthognathic surgery is with the use of orthodontic appliances. Lugs are desirable to be incorporated into these appliances. Different types of surgical lugs available are soldered lugs, crimp-on lugs and Kobayashi ties.

In addition to intermaxillary fixation, traditional methods of fixation included trans-osseous wiring, circum-dental wiring, circum-ramal wiring and circum-mandibular wiring using stainless steel wires. These methods, when used along with IMF, provided good immobilisation of segments.

Over the past several decades, many devices for rigid internal fixation (RIF) have been developed, and it has now become the most popular form of fixation during orthognathic surgery. Stainless steel, Vitallium, pure titanium and titanium alloy are the materials commonly used for rigid fixation. Though titanium is the most popular material because of its superior biocompatibility, Vitallium is the strongest of these options.

The advantages of RIF are

  1. improved intra-operative control over bony segments,
  2. occlusion can be evaluated upon completion of surgery,
  3. allowance for intra-operative strategic flexibility,
  4. better post-operative patient comfort, leading to enhanced speech, hygiene, nutrition and psychological state
  5. faster bony healing, rapid and safer recovery
  6. early mobilisation of the jaw and a more rapid return of jaw function

The disadvantages of RIF are

  1. more instrumentation is necessary
  2. technically more difficult to perform
  • chances of condylar malpositioning, causing TMJ pain or dysfunction
  1. improper fixation would lead to post-surgical problems
  2. increased risk of infection
  3. more expensive
  • a second surgery is required for hardware removal.

Rigid fixation may be accomplished using lag screws or miniplates. Several different screw and plating techniques are useful for stabilising the variety of mandibular osteotomies.

True lag screws have threads only at the distal end of the screw. The outer hole in the lateral cortex is drilled larger than the diameter of the screw threads. This leads to a compressive force between the proximal and distal segments when tightened. Though this might enhance bone healing, there is a disadvantage that any gap present at the osteotomy site may lead to lateral displacement of the condyle. Position screws engage both proximal and distal segments. In this situation, the hole is drilled equivalent to the diameter of screw threads in both cortices. The screws may be placed trans-orally or percutaneously.

Miniplate fixation is another form of RIF option in orthognathic surgery. The plate is attached only to the lateral cortex (monocortical), thus minimising the risk of inferior alveolar nerve damage. Single plate fixation and double parallel plate fixation has been tried after BSSO. For vertical ramus osteotomies, miniplates offer sufficient strength, but percutaneous approach is required. Subapical and body osteotomies are easily fixed with miniplates, but one must take care not to damage the tooth roots. The symphyseal osteotomies are now routinely fixed with lag screws or miniplates at the lower border to prevent relapse.

In 1991 Foley & Beckman compared the rigidity of three rigid internal fixation techniques after mandibular advancement. The fixation techniques were

  1. Three 2.0 mm Champy screws placed bicortically in an inverted ‘L’ pattern.
  2. Two 2.7 mm Wurzburg screws placed bicortically 1 cm apart, parallel to occlusal plane.
  3. A single 4 holed miniplate secured with monocortical screws.

The results showed no significant difference in rigidity between inverted L group and miniplate group while two 2.7 mm bicortical screws had less rigidity.

In 1996 Shetty et al showed that use of both miniplate and bicortical screws showed better results than using them alone.

Post-operative care

Post-operatively, the patient should be observed closely for at least 24-48 hours. Often the endotracheal tube will be retained for several hours post-operatively and sometimes until the following morning. This would prevent the distressing waking and sleeping episodes due to obstruction of the nasal and oral airways. Since many of the patients will have intermaxillary fixation, vomiting and restlessness should be avoided by suitable medication. Also, a suction apparatus as well as emergency instruments including a tracheostomy set, wire cutters and scissors should be kept ready at the bedside.

As the patient has been deprived of fluids for several hours even prior to surgery, the daily requirements may be furnished by intravenous infusion during the day of surgery. If excessive blood loss has occurred, part of the replacement may be in the form of whole blood. Though saline infusions may be used, the bulk of fluid replacements is usually in the form of 5% glucose in distilled water or Ringer’s lactate solution.

Once the patient is fully conscious and the blood pressure normal, the head is raised to 30° to reduce facial oedema. High doses of steroids such as methyl prednisolone or dexamethasone tend to reduce the soft tissue swelling and a regimen should be instituted immediately before or during the operation. Post-operative use of suction drains, ice packs, pressure dressings and continuation of steroid therapy for a few days tend to reduce oedema and haematoma. Routine antibiotic therapy is a matter of judgement, but it is mandatory in intra-oral operations. Pain may be controlled by administration of appropriate analgesics.

Care of the lips is important as minor trauma may occur at the commissures due to excessive stretching during the operation over prolonged period of time. Any gross swelling of the lips may be reduced by the use of vaseline or steroid creams for a few days.

If the patient has not voided within 6 to 8 hours after surgery, catheterisation is indicated. If normal bowel movements have not returned by the 3rd day, an enema should be ordered. Early ambulation hastens recovery.

Non-absorbable sutures are removed on the 5th post-operative day. Careful oral hygiene and use of antiseptic mouthwash help in reducing incidence of infection. Adequate nutrition during the post-operative period is essential for rapid recovery and bone healing.

The intermaxillary fixation is released after 4 to 6 weeks, after which post-surgical orthodontics is started.

Complications

Haemorrhage

Intra-operative life threatening haemorrhage is a rare complication of orthognathic surgery. Bleeding during BSSO is almost always diffuse immediately after the split and often diminishes spontaneously after a few minutes. However, one might encounter significant haemorrhage from inferior alveolar artery, masseteric artery or retromandibular vein. The bleeding that occurs during vertical ramus osteotomy is from maxillary vessels. The body osteotomies might be encountered by bleeding from inferior alveolar artery or facial artery

If the bleeding is from a large vessel that can be visualised, immediate clamping and ligation may be done. Otherwise, simple packing is done for some minutes. If this does not control bleeding, ligation of the external carotid artery may have to be resorted to.

Haematoma formation is a complication in condylar resections and genioplasties. It is a potential risk in ramus and body osteotomies as well. Post-operative pressure dressings may aid in controlling minor soft tissue bleeding and prevent haematoma formation, but cannot substitute for good intra-operative hemostasis.

Nerve injury

This is one of the most common complications of mandibular surgery. The incidence of post-operative dysfunction of inferior alveolar nerve is greatest in body osteotomies, but it is seen to a lesser degree in sagittal split, and even more rarely in vertical ramus osteotomies. The causes of nerve trauma are cutting too close to the mandibular foramen, bruising / transecting the nerve, pressure on the nerve while repositioning the segments, and direct injury to the nerve while applying rigid fixation. In bilateral sagittal split, excessive traction on the nerve superior to the lingula and unfavourable spilts are the primary causes.

In extra-oral approach, injury to the main trunk or marginal mandibular branch of facial nerve, are likely occurrences.

The neurosensory disturbances are usually transient, lasting for weeks to months. The duration and severity of the problem is directly related to the degree of trauma inflicted on the nerves. Direct nerve injury, such as transection, requires immediate microneuronal repair for optimal recovery.

Unfavourable osteotomy

This complication is most likely to be found in cases of BSSO and the incidence is between 3% and 20%. The unfavourable splits may cause fractures of the proximal or distal segment. The most common factor causing a proximal segment fracture is the failure to cut the inferior border prior to applying chisels to the osteotomy. When this occurs, the fracture line propagates along the buccal aspect of the inferior border. Adverse distal segment fractures may be splits that are short of the lingula, medial splits up the condyle and those occurring just distal to the second molar. The same accident can occur in any osteotomy site if segments are mobilised before adequately deepening the bur/saw cuts.

Strained condylar position

Many procedures involving displacement of the mandibular segments cause the condyles to lie in an abnormal position. The displacements most often noted are condylar sag, anterior displacements and rotations about the vertical axis. These might cause post-operative discomfort and pain.

Poor aesthesis

Even if preceeded by meticulous treatment planning and surgical implementation, orthognathic surgery occasionally produces unexpected aesthetic results. Following reduction genioplasty and correction of severe mandibular prognathism, drooping of soft tissue of the chin may occur. This is most easily corrected by a triangular excision of skin and fat in the submental area. The apex of the triangle is at the symphyseal midline and the lateral incisions are parallel to the lower border of the mandible. The base of the triangle is the submental crease. The incision is closed to produce an inverted ‘Y’ scar. Another option is to attempt submental liposuction.

Unaesthetic scar is an obvious complication of extra-oral approach for any procedure. Unless otherwise deemed necessary, it is always advisable to opt for intra-oral approach.

Malocclusion

Every case of mandibular prognathism or retrognathism requires some period of post-surgical orthodontics to fine-tune the occlusion. In cases of mandibular excess, the occlusal problems noted are

  1. Class II malocclusions or mandibular asymmetry, appearing soon after the function is resumed,
  2. A relapse towards renewed mandibular excess and
  • Lateral open bite developing several months after surgery.

Wound dehiscence

Wound dehiscence is a possible complication in body osteotomies, genioplasties and segmental procedures. This is more common in situations where incision is placed in the buccal vestibule. In order to prevent this, it is important to close the wound without tension especially in advancement cases. Most dehiscences are managed without resuturing, and are left to heal by secondary intention.

Loss of osteotomised segment

This is the direst complication in orthognathic surgery. This can result in genioplasties and in segmental procedures if the lingual soft tissues are not protected, resulting in a decrease of blood supply. Excessive resorption or avascular necrosis can be avoided by maintaining a broad vascularised soft tissue pedicle. This is accomplished by minimal stripping of soft tissues overlying the symphysis and maintaining as much of lingual muscle attachments as possible.

Tooth loss

Though the number of reported cases of tooth loss following surgery is quite low, damage to the teeth with prolonged recovery of tooth vitality is more common. The higher incidence of tooth related complications in mandibular procedures has been attributed to the nature of mandibular vascular and nervous supply, differences in tooth length, the greater difficulty of the procedure in the mandible and the position of the bony cuts.  Teeth adjacent to the osteotomy are most often affected either by loss of vitality or by iatrogenic periodontal defects. It is recommended that the horizontal osteotomies should be placed at least 5 mm from the apices of teeth in order to preserve pulpal circulation.

Relapse

Relapse following mandibular advancement has been well documented. Van Sickels et al (1986) concluded that relapse is to be expected with mandibular advancements greater than 7 mm. The methods recommended for correction or prevention of skeletal relapse include extended periods of skeletal fixation, suprahyoid myotomies and orthodontic overcorrection.

There is evidence that at least five factors affect post-operative stability.

  1. Amount of displacement of the segments. The likely reason for this phenomenon is the excessive tractional forces from the pterygo-masseteric sling and suprahyoid musculature.
  2. Displacement of the condyle.
  3. Rotation of the proximal segment
  4. Type of proximal segment and
  5. Residual growth.

Distraction osteogenesis

Distraction osteogenesis is the slow application of force to a bone gap, resulting in the production of new bone and soft tissues. An osteotomy is made in the area of bone deficiency and an appliance placed and utilised to separate the bone edges. As the bone edges are advanced, the overlying soft tissue envelope is also stretched, inducing hyperplasia of the adjacent soft tissues. The bone gap is initially filled with fibrous connective tissue. If adequate stability of the new generate is maintained, direct ossification of the collagen occurs. Once adequate bone regenerate has been formed, it is held in neutral fixation, allowing for complete ossification of the new bone matrix.

The concept of bone lengthening was first described by Codvilla (1905) for femur lengthening. Gavriel O. Ilizarov (1965) with his colleagues elucidated the rate, rhythm, amount and type of force that optimises the technique in long bones. These basic axioms are commonly referred to as Ilizarov principles. In 1973, Snyder et al studied the application of distraction concepts to the mandible. Michelli and Miotti (1977) demonstrated gradual lengthening in canine mandibles. McCarthy et al in 1992 demonstrated the technique in human mandibles. In 1992, Guerrero and Constasi described in detail the orthodontic principles of mandibular lengthening via distraction osteogenesis.

The distraction osteogenesis protocol includes

  1. Fixation of the distractor and body osteotomy
  2. Latency period of 7 days to allow primary healing of soft tissues
  • Distraction, performed at a rate of 1 mm daily
  1. Stabilisation period of 8 to 12 weeks before any orthodontic movement is started.

Recent advances

Lapori et al (JOMS 1997) performed BSSO in outpatient setting in 90 patients under ambulatory anaesthesia and reported no complications and only three unanticipated admissions.

A new technique for intra-oral inverted ‘L’ osteotomy was described by McMillan et al (BJOMS1999). The procedure included fixing the proximal segment to the maxilla before doing the osteotomy. This is to prevent rotation of the proximal segment after the osteotomy.

Tbaranon (JOMS 1998) compared the rigidity of bicortical screws and a miniplate for fixation of a mandibular setback after a simulated BSSO. The biomechanical stability of 3 bicortical screws with that of a single four holed miniplate after 5mm mandibular setback in cadaver were compared. He found no significant difference between the two.

A technique called ‘extended sliding genioplasty’ was introduced in1995 by Varghese Mani as a camouflage treatment for facial asymmetry secondary to TMJ ankylosis. The advantages of the technique is that while not undertaking complicated double jaw procedures, it maintains the functional occlusion, as well as corrects the asymmetry and the apparent deficiency of mandibular body on the unaffected side.

Intra-oral distraction osteogenesis was first discussed by Guerrero and Bell in 1995. In 1996, Chin and Toth also described the intra-oral procedures. In 1996, Bell, Harper and their colleagues studied the histology of tissues while doing distraction osteogenesis for mandibular widening. In 1997, Guerrero et al compared the efficacy and complications of tooth-supported devices with bone-supported devices. They found that the bone-supported devices have several advantages over the former.

Raghoebar et al (Int J OMS 2000) demonstrated vertical distraction of severely resorbed mandibular alveolus using Groningen distraction device. The device can be snugly attached to the alveolus, and its screws are later replaced by endosseous implants.

Conclusion

Pleasing aesthetic characteristics vary widely among cultures. With the techniques of orthognathic surgery combined with adjunctive procedures, it is now possible to correct facial deformities of any degree. Accurate diagnosis of the problem, assessment of the severity of the deformity, prediction procedures like prediction tracing and model surgery, meticulous treatment planning and surgical implementation and above all, good team effort will all be helpful in achieving a predictable surgical outcome.

References:

  1. Historical developments of orthognathic surgery. W. Steinhauser. Journal of Cranio-Maxillofacial surgery. 1996: 24: 195 – 204.
  2. Mandibular prognathism. David Hall, Ronald Hathaway. Mandibular deficiency. David J. Darab. Modern practice of orthognathic and reconstructive surgery. William H. Bell. B. Saunders company. 1992. Vol. III. 2110 –2140, 2334-2517.
  3. Orthognathic Surgery. edited by J. Betts, T. A. Turvey. In Oral and Maxillofacial Surgery. edited by R. J. Fonseca. W. B. Saunders company. 1992. Vol II.
  4. Surgical Correction of Dentofacial Deformities. Bell, Profitt and White.
  5. Aesthetic Surgery of the face. Varghese Mani
  6. Textbook of Oral and Maxillofacial Surgery. Gustav O. Kruger

 

 

Posted in Orthognathic Surgery

Orthognathic Surgery – Midface procedures

Orthognathic Surgery – Midface procedures

Introduction

Orthognathic surgery has evolved over many years to correct both facial deformity and oral dysfunction. Facial beauty is difficult to define in precise terms because subtle differences between individuals can produce marked aesthetic contrasts. Furthermore, different racial forms of beauty are not comparable and so ethnic norms are required to correct the abnormality. Despite this skeletal abnormality is recognisable, measurable, and usually correctable by orthognathic surgery.

Orthognathic surgery started as “Orthodontic surgery’ as an aid to orthodontics, later graduated to orthognathic surgery as a remedial measure to orthodontic limitations.

Orthognathic surgery is mainly directed at the correction of basal bone defects. The aim is to attain aesthetic, psychological and functional rehabilitation of the patient. However  fine tooth movements for the optimum results are difficult to obtain with orthognathic surgery alone. Such finer adjustments can be achieved by orthodontics. Orthognathic surgery along with rhinoplasty and orthodontics can rehabilitate patients with facial deformities and oral dysfunction.

Historical events

Hullihen was the first person to correct jaw deformity surgically in 1849, when he corrected an anterior open bite by mandibular subapical osteotomy.          Orthognathic surgery of the maxilla was first described in 1859 by Von Langenbeck for the removal of nasopharyngeal polyps. Cheever 1867 reported a maxillary osteotomy for complete nasal obstruction secondary to epistaxis, he used a right hemimaxillary down fracture. Later many maxillary osteotomy techniques were described for the treatment of pathological process.

Blair in the early 1900’s was the first to classify  jaw deformity into five classes as : Mandibular prognathism, Mandibular retrognathism, Alveolar mandibular protrusion, Alveolar maxillary protrusion and open bite.

In 1901, Le Fort published his classic description of the natural planes of maxillary fracture. Cohn-stock 1921 described segmental osteotomy of maxilla which was modified by Wassmund (1926) by a labial approach. Cupar 1954, Kole 1959 and Wunderer 1963 reported a direct surgical access to these procedures which improved mobilisation and maintained blood supply. Wassmund (1927) described a total horizontal maxillary osteotomy to close a posterior open bite and this constitute earliest work of Le fort I surgery.  Axhausen (1934) performed the first total mobilisation of the maxilla.

Posterior segmentalization of the maxilla was first used by Schuchardt 1959 for correction of open bite. This had limited stability owing to its incomplete mobilisation. Kufner 1970 improved on this technique by completely mobilising the osteotomized segment prior to repositioning.

Paceno (1922) published some basic principles of roentgenographic cephalometry which was later modified and popularised by Broadbent and Holfrath (1935).  Down (1945) put forward some standard measurements which helped the diagnosis of deformities of midface. Burstone et al 1978 & 1980 gave an analysis for the assessment of dentofacial deformity using cephalometric radiographs ” The cephalometric analysis for Orthognathic surgery” (COGS).

Use of bone grafts in midface surgical advancement were reported by Rowe (1954), Cernea and associates (1955), Lerinac (1958).

Separation of the pterygomaxillary junction was first advocated by Schuchardt in 1942. Moore and Ward 1949 recommended horizontal transection of the pterygoid plates for advancement. This technique was associated with severe bleeding so Wilmar advocated the pterygomaxillary disjunction technique for Le fort I osteotomy.

A combined form of anterior and posterior subapical osteotomies “total subapical maxillary osteotomy” were reported by Paul 1969 for midface hypoplasia.. This technique was further described by West & Epker 1972, Hall & Roddy 1975, Wolford & Epker 1975, West and McNeil 1975 and Hall & West 1976.  Maloney (1982) reviewed this technique and described it as a good technique during his time. This technique is hardly in use now.

Hugo Obwegesser 1965 advocated complete mobilisation of maxilla so that maxilla could be repositioned without tension. This aided in stabilisation which was documented by Haller, Hogemann & Wilmar and Perko.

Hugo Obwegesser 1969 described a high quadrangular Le Fort I osteotomy for midface deficiency correction. This technique was later named as Quadrangular Le Fort I osteotomy by Keller & Sather 1989.

Converse & Colleagues in 1970 described an osteotomy at Le Fort II level but this had several biologic and anatomical flaws so this technique did not have appreciation later. Henderson & Jackson 1973 described a classic Le Fort II osteotomy for correction of midface deficiency.

Kufner 1971 described an osteotomy procedure for midface deficiency correction, which was named as quadrangular Le fort II osteotomy by Steinhäuser 1980. This technique was modified by Stoleinga & Brown in 1996 which prevents damage to infra orbital nerve.

Vascular supply of lower maxilla and alveolar portion was extensively studied by Bell and Levi (1971) and Bell et al (1979).  They concluded that the vitality of segment will not be affected if either palatal or buccal flaps were retained undisturbed.

Epker and Woodford 1980 gave a detailed down fracture technique for Le fort I maxillary osteotomy based on palatal flap.  They advocated the use of same for anterior  maxillary segment 0steotomy.

Sir Harold Gillies & Harrison 1950 performed Le Fort III osteotomy for midface deficiency.

Paul Tessier 1967 described various techniques for correction of orbito-craniofacial deformities.

The first use of bone plating was carried out by Soerensen in 1917 for fracture mandible. Bernd Spiessl 1974 was the first to use rigid fixation after sagittal split osteotomy. Use of rigid fixation to stabilise osteotomised segment was reported by Champy & associates 1976, Mischelet, Leyoness & Desus 1973, Dromer and Luhr 1981, Steinhäuser 1986 etc.  Miniaturised plates were used by Luhr 1981, Steinhäuser 1986 etc. Miniaturised plates by Luhr, 1989 solved the problem of excessive bulk of miniplates for use in midface.

The latest developments in orthognathic surgery is the use of adjutant plastic surgical procedures like blepharoplasty, rhinoplasty, rhitidectomy, liposuction , lip correction and the use of the principle of distraction osteogenesis for correction of jaw deformities.

Anatomy of midface

The skeleton of midface is made up of intricate attachment of various bones, these include two maxilla, two nasal bones, two palatine bones, two zygoma and their temporal process, two inferior nasal conchae, the vomer, the ethmoid and the pterygoid process of the sphenoid bones. The articulation of these bones give the projection to midface. Any excess or deficiency in this region produces an unaesthetic deformity.

The midface is in relation to important aesthetic and functional landmarks such as the orbit, nasal cavity, maxillary sinus and the oral cavity.

The maxilla is a paired bone of the upper jaw, fused to form one central focus of the midface. It acts as a base for containing the teeth, support for nasal cartilages, gives attachments to muscles and forms the major bony plate for palate and orbit. Each hemimaxilla contain a large pyramidal shaped body, the maxillary sinus and four prominent process – the frontal, alveolar, zygomatic and palatine process. The body of maxilla is hollow and contains the maxillary sinus. The infero lateral walls of the maxilla are thinner and are directed in a angular fashion with narrower bottom and gradually increasing in size superiorly. So an osteotomy cut in this area would result in telescoping of the inferior segment into the antrum and resulting in instability. The frontal process arises from the anteromedial corner of the body of maxilla and it articulates with nasal bone, frontal bones to form the medial wall of the orbit. The zygomatic process of the maxilla arises from the anterolateral corner of the maxilla and articulates with zygoma laterally. They together form the floor and lateral wall of the orbit. The highly vascular nasal mucosa is loosely attached to the rim of the pyriform ring of the maxilla. This can be easily raised from the palatine process of the maxilla. The infraorbital nerve and vessels pass through the infraorbital foramen which lies at the anterior surface of the maxilla below the infraorbital rim. A damage to this nerve is most likely in Le fort II and III procedures and this would produce profound paresthesia / anaesthesia of the upper lip and part of nose.

The zygoma is a paired bone and makes up the essence of the cheek prominence. It is diamond shaped bone. Its deficiency along with infraorbital deficiency would result in increased visibility of sclera. This has four process by which it attaches to frontal bone, maxilla and temporal bone.

Nasal bones are rectangular and articulate with frontal bone and process of frontal and maxilla. This gives the anatomic projection to the nasal bridge.

Palatine bones are paired bones which connect the maxilla with the sphenoid bone through pterygoid plates. It has a body and two process the horizontal and vertical.  The greater and lesser palatine nerves and vessels pass through this bone. Posteriorly this bone articulates with pterygoid plates. This articulation is disjuncted during total maxillary osteotomies when maxilla is to be advanced or impacted superiorly.

The inferior nasal concha is a paired bone that form the bony support of the inferior turbinates bilaterally. In some instances this might be enlarged which makes superior impaction of maxilla difficult.

Biological basis for maxillary osteotomies.

The delivery of an adequate amount of blood to the tissue capillaries for normal function of the organ is the primary purpose of the vascular system. Successful transportation of the maxillary dento-osseous segments by Le fort I osteotomy depends on preserving the vitality of the segment by proper design of the soft tissue and bone cuts.

Extensive studies on the blood supply of maxilla by Bell & Levy 1969 and others have shown an extensive anastomosis between the terminal branches of the maxillary vessels. This allows a wide range of buccal and palatal flaps to be raised. Formerly tunnelling procedures have been used to maintain a dual supply from the tissues of the cheek and palatal vessels. Studies by Bell & Levy 1969 have shown that interruption of these, for example the palatine vessels, will not lead to necrosis of bony segments, provided adequate buccolabial periosteal flaps retained.

Maxilla receives its blood supply from branches of maxillary artery – the palatine artery and superior alveolar arteries. It also receives collateral supply from the branches of facial artery. The collateral circulation within the maxilla and its evolving soft tissues and the many vascular anastomosis in the maxilla, permit numerous technical modifications of the Le fort I osteotomy.

You et al 1991 studied the vasculature of the maxilla. He stated that

  1. normal blood supply of the maxilla originates centrifugally from the alveolar medullary arterial system.
  2. The mucoperiosteal arterial system also gives off many branches that penetrate the cortical bone and supply the maxilla.
  3. The vascular connections between the maxilla and the surrounding soft tissues consist of not only the capillaries but also arteries and veins.

These multiple source of blood supply to the maxilla and abundant vascular communications between the hard and soft tissues constitute the biological foundation for maintaining dento-osseous viability despite transection of the medullary blood supply after maxillary osteotomies.

So for anterior maxillary osteotomy when a labial mucoperiosteal flap is reflected , the collateral circulation is from the palatal vessels, care has to be taken not to damage the palatal vessels. When a palatal mucoperiosteal flap is raised for osteotomy then the labial vessels has to be preserved.

Bell 1969, Bell & levy 1971 have demonstrated the viability of large or small segments of the maxilla when vascular pedicles from the palatal, facial or both mucosal surfaces were not  detached from the osteotomised segments. They also observed that ligation of the greater palatine arteries bilaterally did not adversely affect the outcome of the surgery when adequate palatal mucosa and labiobuccal gingival pedicles were maintained.

Azaz & Shteyer 1977 and Westwood & Tilson 1975 observed that the most common complication in surgery with multiple segments is the loss or devitalization of an occasional tooth adjacent to the interradicular osteotomy site.

Studies by Justin et al 2001 has shown that there is a hyper-vascularity  in the pulpal and gingival tissue during healing ( 2nd –3rd week) after maxillary osteotomies.

Timing of surgery

As a rule of thumb it is better to wait till the skeletal growth is completed before doing orthognathic surgery. There has been report in literature to support the corrective surgical measure even during the growth period, specially if there is compelling psychological need for such intervention in the patient.

Maxillary growth usually ceases 2 years before mandibular growth completion but there is a difference of 6 years in late maturers. Post menarche growth of maxilla is negligible. Radius epiphyseal fusion is a definite indicator of completion of maxillary growth.

Surgical correction for maxillary excess is not contraindicated during growth period as reduction in growth of maxilla helps in the surgical measure for the patient.

Surgical approach to Midface.

Surgical treatment of dentofacial deformity was not undertaken until the beginning of the twentieth century due to difficulties in access to facial bones and the problems of anaesthesia.

Early surgeries were directed towards mandible mainly through the extra oral approach which had the disadvantage of visible scar. The maxillary procedures were initially linked to the management of cleft problems. Wasmund 1935, Axhausen 1937 & 1939 and Schuchardt 1942 developed approaches initially to anterior maxilla and later to posterior and whole maxilla.

Requirements of  approach to facial bones.

There are number of prerequisites for approach to facial bones, these include.

  1. This must be a safe approach which allows a clear view for placement of bone cuts and gives a good access for instruments.
  2. While placing incisions thought must be given to possible problems such as proximity to vital structures, scarring and infection.

The important structures include large  vessels and nerves like facial nerve and vessels, infra orbital nerves and mental nerve, nasolacrimal duct, canthal ligaments, external auditory canal etc.

The access to the facial bones can be broadly classified into two categories : transcutaneous and intraoral.

The best access is through skin but this leaves a visible scar. The skin incisions should be placed in such a way that it is hidden or follow natural skin creases.

The intraoral approach avoids scarring but it provides relatively poor visibility and access difficulties. Often special instruments are required with this technique.

Extra oral approaches to midface.

Le fort I osteotomy is approached entirely through the intraoral approach, while Le fort II and Le fort III might require incisions around the orbit. These incisions are to be placed in such a way that it minimises scarring and also does not effect functional limitations. A variety of incision have been used for accessing midface. These include.

  1. Trans conjunctival incision.
  2. Medial canthal incision.
  3. Infra orbital incision.
  4. Blepharoplasty incision.
  5. Extended eyebrow incision.
  6. Bicoronal incision.
  7. Incisions to approach naso-orbit area.

Trans conjunctival incision

This incision is used when access to the infra orbital region is needed during Le fort II and III osteotomies.

Here the incision is placed in the inferior fornix. Care is taken to avoid damage to lower lid tarsal plate and also to cornea. Cornea is protected by suturing the upper edge of conjunctival incision to the upper lid margin during the operative procedure. Blunt dissection down exposes the periosteum on the orbital floor which is incised at the infra orbital rim.

A fine catgut is used to close conjunctival incision.

Medial canthal incision

This incision is required to provide access to the bridge of the nose and medial orbital area during Le fort III osteotomy. This incision can be extended laterally for greater access to lateral infra orbital region.

The incision is made from a point just superior and medial to medial canthus to approximately midpoint between the lacrimal duct and infra orbital nerve. The incision passes through skin and superficial fascia, splitting orbicularis oculi onto the periosteum. This provides access to the anterior maxilla medial to the infra orbital nerve and also to nasal bones. The periosteum is stripped from over the infra orbital margin and along the floor of the orbit around and behind the nasolacrimal duct. Periosteum is also stripped from the nasal bones superior to medial canthal ligament.

Visible scarring is minimal with this type of incision but when incision is extended laterally below the infra orbital region it produces a visible scar.

Blepharoplasty incision

This incision is used for accessing the malar region and also for naso orbital procedures in Le fort III osteotomy. This incision is more aesthetic than infra orbital incision.

Here the incision is made in the skin 1 – 2 mm below the grey line at the lid margin. The skin is undermined superficial to the orbicularis oculi muscle which is then split at the infra orbital margin. Dissection is done while taking care to prevent damage to the orbital septum. The periosteum over the maxilla is divided 1 to 2 mm below the infra orbital margin. By this approach antromedial malar osteotomy cuts can be placed. When a wider exposure is required the incision is extended laterally through crow’s foot crease.

The incision is closed in layers, first the periosteum, the muscle and finally the skin with fine subcuticular nylon sutures.

Extended eyebrow incision

This approach is for access to lateral orbit .

The incision is made through the lateral part of the eyebrow and along its length parallel to hair follicles. This should not be extended beyond lateral canthus as it produces a visible scar. This incision provides good access to the frontozygomatic suture and allows for bony cuts to be placed through the lateral orbital wall down to the inferior orbital fissure. The incision is placed through the skin, superficial fascia, orbicularis oculi and deep fascia down to periosteum. The periosteum is incised at the anterolateral aspect of orbital margin. Bleeding is profuse which is controlled by diathermy.

Wound closure is done in layers.

Naso orbital area exposure

Exposure of this area is difficult.

The midline vertical incision down the nose provides access to both the medial canthus area, but often leaves a persistent scar.

A horizontal or inverted ‘V’ cut extended from two canthal ligament again has the scar visibility. For approach to upper nasoethmoid area a horizontal incision from one eyebrow to other is preferred. For nasal lengthening procedures as along with  Le fort II an inverted ‘V’ or ‘Y’ incision is preferred. Tension in the suture area is to be avoided as it is likely to spread the scar.

For Le fort III the approach to the whole of this area is best by a bicoronal incision.

Bicoronal incision

The bicoronal ( bitemporal, bifrontal ) flap probably provides the best access to the upper face. It is essentially a continuation of the preauricular incision which is carried superiorly across the scalp. In the midline the incision is directed slightly anteriorly to allow for easier closure and for easy mobilisation of soft tissues. It must remain within the hairline particularly in males. In children this incision should not be brought forward as the scar tends to drift anteriorly as the child grows.

The incision is first marked and it is made through the skin, superficial fascia and galea. The line of separation is obtained in the loose areolar tissue above the pericranium. Dissection is done anteriorly and inferiorly in a plane temporalis fascia and pericranium. Approximately 2 cm above the orbits the pericranium is incised in a curved fashion forward from one orbital margin to another and this is stripped off with the anterior flap. This flap is reflected over the bridge of the nose to expose the frontonasal suture, the supra orbital rims and lateral orbital margins. Further exposure is gained through a vertical incision through the periosteum overlying the bridge of the nose. The supra orbital neurovascular bundles are preserved and freed whenever necessary by cutting a foramina with a small chisel.

For Le fort III osteotomy the soft tissues incision is extended down to the zygomatic arch by incising the periosteum on the temporal surface of the orbit and the temporalis muscle retracted posterolatrally to expose the medial wall of the malar bone. The periosteum is raised along the orbital margin from the lateral, medial and superior walls. By this approach the whole of orbit, malar  and frontonasal suture are exposed. It also gives good access to temporomadibular joint and nasoethmoid complex region. To avoid excessive bleeding, it is important to maintain a good hemostasis with the use of Raney clips along the flap margins.

After the operations are completed the scalp flap is replaced and the wound closed in layers with two scalp suction drain in place. Pressure dressing are given to avoid haematoma formation.

The intraoral approach

The great majority of the maxillary procedures are performed through an intraoral approach. Scars in the midface are to be avoided if at all possible as they cannot be hidden well and are usually unnecessary. Majority of Le fort I osteotomies and segmental osteotomies of Maxilla are done through an intraoral incision.

Extensive anastomosis between the terminal branches of the maxillary vessels allows for a wide range of buccal and palatal flaps to be raised. Formerly tunnelling procedures have been used to maintain a dual supply from the tissues of the cheek and palatal vessels. Now osteotomy of  maxilla is done based on the palatine vessels or on the labial / buccal vessels.

Incisions for Le fort I osteotomy

The incisions used for Le fort I osteotomies include

  1. Tunnelling approach
  2. Down fracture approach
  3. Approach in the cleft patient : Henderson – Jackson
  4. Approach in the cleft patient : Converse – wake.

Tunnelling approach:

This type of incision was used during 1950 – 1970s. Here Le fort I osteotomy is done through three incisions. Here a horizontal incision is placed in the vestibule of first molar region bilaterally and a third incision is placed vertically in the midline anteriorly. The anterolateral wall of maxilla is sectioned through the lateral incisions. The nasal septum is detached through the midline incisions. The lateral nasal wall is fractured through midline incision using Rowe’s disimpaction forceps. This causes tearing of nasal mucosa. By this approach limited repositioning is only feasible due to poor accessibility.

Down fracture approach :

This technique developed  by Bell 1975 has changed the approach to maxilla, aiding in positioning maxilla in all the planes and cutting the maxilla into varying pieces without risk of loss of segment. This procedure can be done under direct vision with less blood loss. Here the incision is made high in the maxillary vestibule from one second molar region to other lying just above the buccal/ labial attached gingiva. The mucoperiosteum is raised over the superior maxilla, round the pyriform aperture, the malars and the infra orbital area.  Only minimal periosteal stripping is done in the dentoalveolar region in cases of adjutant segmental osteotomies. The nasal mucoperiosteum is raised along the floor of the mouth which helps in detaching nasal septum and also perform lateral nasal osteotomy cuts without tearing nasal mucosa.

Approaches in cleft lip & Palate:

Henderson and Jackson 1975 devised a useful approach for the management of maxillary hypoplasia in cleft lip case. They advocated splitting the lip through to the cleft line and then extending this incision into the labial sulcus on either side. To close the fistula, a buccal flap is reflected from the lesser segment side and it is rotated into the cleft alveolus to provide closure to the oral layer. The nasal floor mucoperiosteum is raised from the septum and lateral wall of the nose and closed under direct vision. Sometimes mobilisation of palatal tissues is necessary to close the palatal cleft.

To overcome the problem of palatopharyngeal scaring and the resultant velopharyngeal insufficiency Wake 1975 modified the Converse approach to Le fort I osteotomy by leaving behind the palatal tissues. Here vertical incisions right angle to the dental arch are placed anteriorly in the midline and laterally in the buccal vestibule molar/ premolar region. By tunnelling approach maxillary osteotomy is completed. A palatal flap is raised a few millimetres from the gingiva with the palatine vessels contained in it. The palatal flaps are raised  up to the greater palatine canal. The posterior osteotomy cuts are placed anterior to the greater palatine canal and the maxilla is positioned anteriorly leaving behind the palatal flap. The anterior raw area is allowed to granulate secondarily. This approach diminishes the risk of speech changes but it is a difficult procedure and the osteotomy sites takes longer period to unite.

Incisions for segmental procedures

Segmental osteotomies are done on the maxilla, these include the anterior maxillary osteotomy and posterior maxillary osteotomy.

The approaches used for anterior maxillary osteotomy are

  1. Wassmund’s approach
  2. Wunderer’s approach
  3. Down fracture approach (Bell down fracture modification of the Cupar technique).

 

The posterior maxillary osteotomy is approached  by

  1. Buccal approach ( Kufner).
  2. Buccal & Palatal approach ( Perko – Bell).

Approaches to anterior maxilla

Wassmund approach

The Wassmund approach relies on the buccolabial vascular pedicles and usually an intact palatal blood supply.  An anterior median vertical and buccal vertical incisions are made. Buccal bone is removed through the buccal vertical incision up to the pyriform aperture by tunnelling approach. Palatal bone is removed by tunnelling approach under the mucoperiosteum from the socket area. Sometimes a small midline palatal incision aids removal of palatal bone. The nasal septum is approached through the anterior vertical incision. By this approach it is difficult to raise the maxilla and to setback posteriorly.

Wunderer  approach

In the Wunderer  approach, a transverse incision is placed across the hard palate in addition to the three vertical incisions described by Wassmund’s technique. This allows better access to the palate for major posterior movements. The transverse palatal incision is arched forward so that the suture will lie on the anterior palatal bone. The buccal bone and septum is approached through the vertical incisions as in Wassmund’s approach. The anterior segment is hinged on its labial pedicles.

Down fracture approach

The down fracture approach is the most widely used procedure for anterior maxillary osteotomy as this provides good access and also reliable blood supply. Here a vestibular incision is placed in the labial vestibule. The buccal osteotomy cuts are done through tunnelling approach. The nasal mucosa is raised and the nasal septum detached through the vestibular incision. Any midline splitting is done before the completion of segmental osteotomy.

Approach to posterior maxilla

The approach to posterior maxilla, usually for raising the buccal segment, may be through the buccal and palatal mucoperiosteal incisions.

Kufner 1970 described a single buccal incision approach. This approach is difficult in flat palate and when antral walls are thick.  The buccal bones are cut through the buccal incision and the vertical cut in the premolar region is done through the tunnelling approach. The palatine bone is cut by using a fine curved osteotome. When a palatine incision is planned it should be made medial to the palatine foramen and the osteotomy is performed lateral to the foramen.

When the palate is very flat the Perko – Bell technique (1967) may be adopted. Here both walls of the antrum are cut through the buccal approach. A parasagittal incision is made in the palate from premolar area to the junction of the hard and soft palate and the alveolar bone exposed and cut medially to the greater palatine foramen in an anteroposterior direction.

Besides these, a variety of techniques have been described to deal with individual problems in maxilla. It is best to choose the safest and most reliable one for the situation.

Osteotomy techniques – Maxilla.

A variety of osteotomy techniques have been described to correct the midface problems. The osteotomy techniques include either a segmental osteotomy of maxilla where a part of the maxilla is osteotomised and repositioned or total maxillary osteotomy is done at Le fort I, II, or III level to correct the deformity.

 Segmental surgeries of Maxilla

The types of segmental osteotomies described for maxillary procedure include – single tooth osteotomy , anterior maxillary osteotomy and posterior maxillary osteotomy.

Single tooth Osteotomies

Indication

  1. The procedure is mostly used for dilacerated teeth
  2. Those teeth that have been impacted into the alveolar bone following trauma.
  3. Occasionally when more than one tooth requires repositioning.

Procedure

This procedure is limited to maxillary anterior tooth.  This procedure requires good amount of inter radicular bone. The approach to single tooth Osteotomy is through either a small high horizontal labial sulcus incision or alternatively through two vertical incisions on either side of the tooth.

When using two vertical incisions, these are made through the mucoperiosteum a millimetre or two on either side of the proposed bone cut. The incision starts high in the labial sulcus and stops 2 –3 mm from the alveolar crest. Mucoperiosteum is not elevated over the tooth that is to be repositioned.  Labial bone cut in made with fine burr, in the centre of inter-radicular area parallel to each other.  High in the labial sulcus the mucoperiosteum is elevated ( tunnelled ) above the root apex of the tooth to be moved so that a horizontal cut may be made at least above the apex.  The segment is separated by the use of fine osteotomies.  The osteotomies are angled to the palate on the either side and a finger is kept in the palate to feel the instrument penetrating the palatal bone.  The supra-apical division is similarly made through the palate with a curved osteotome.  Once the tooth segment is mobile it is best to fix it to the adjacent teeth by means of an orthodontic arch and attachments.

In horizontal labial incision technique care is require when tunnelling vertically on either side of the tooth not to detach the labial mucoperiosteum on its anterior surface.  The remaining procedures are same as described before.  Immobilisation of tooth segment is required for several weeks.

Basic surgical principles of single tooth osteotomies are

(1)   Maintain an adequate amount of attached, viable tissue to the mobilised segments in order to provide sufficient vascularity to them.

(2)  Provide maximal direct visualisation of all areas to be osteotomised or ostectomised.

(3)   Achieve good mobilisation of the segments to allow for passive repositioning in the predetermined position

(4)   Maintain operational periodontal health.

(5)   Provide good bony contact between the stable and mobilised segment to effect rapid bone union.

Anterior Maxillary Osteotomy

An initial discussion of anterior maxillary osteotomy was presented by Cohn-stock in 1921.  The single state predominantly labial approach was first reported by Wassmund in (1926).  Axhatusen added a tunnelling procedure on the palatal side (1936),  Schuchhardt (1956) preferred a two stage procedure, with the palatal side being treated  first and completion of surgery 4-6 weeks later from labial approach.

The most popular technique of segmental surgery is the down fracture described by Epker and Welford (1980).

The anterior maxillary osteotomy is primarily employed

  1. – Reposition the dento alveolar segment posteriorly
  2. – Correction of maxillary protrusion
  3. – Bimaxillary protrusion – along with mandible, (anterior segment)
  4. – Correction of openbite (Secondary to mandibular correction)

In certain cases the dento-alveolar protrusion  with or without vertical maxillary excess, it might be difficult to decide between Anterior maxillary osteotomy and a Le fort I osteotomy with an anterior maxillary osteotomy to correct the deformity. In these situations these guidelines might be helpful.

If sufficient overbite exists and an impaction of 3mm or less is required then an isolated Anterior maxillary osteotomy would suffice.

If more than 3mm impaction is required and even if overbite exists le fort I osteotomy should be done in combination with anterior maxillary osteotomy.

If there is negative or minimal overbite, even if the maxillary impaction is minimal le fort I with anterior maxillary osteotomy is indicated.

If the maxillary impaction planned is minimal less than 3 mm, but if the gingival level between the teeth adjacent to the osteotomy has a steep angle, a Le fort I osteotomy with anterior maxillary osteotomy should be planned.

Wassmund technique:  [ Labial vertical incision with palatal tunnelling]

The Wassmund approach relies on the buccolabial vascular pedicles and usually an intact palatal blood supply.

An anterior median vertical and buccal vertical incisions in the canine – premolar regions are made extending to the nasal floor. The mucoperiosteum is reflected posteriorly and superiorly. In the apical region of the canine tunnelling  is carried out to the inferolateral border of the nasal pyriform aperture. Mucoperiosteal flap raised to expose pyriform rim and nasal spine.

Vertical bony cuts are made in the lateral maxillary cortex at the midpoint of planned osteotomy site.  These are carried superiorly to a point approximately 3mm superior to canine apex.  The anterior bony cuts are completed by continuing the cuts medially to a point on the most lateral aspect of pyriform aperture.  These are made with tapered fissure bur.

On palatal aspect a subperiosteal tunnel is created on the area of planned palatal osteotomy. While the palatal tissue are protected with a suitable retractor the bony cut is carried from crest of alveolar bone in one osteotomy site across palate to opposite side.  Care must be taken to avoid damage to nasal floor mucosa and penetration of endotracheal tube. Sometimes a small midline palatal incision aids in the removal of palatal bone.

The nasal septum is approached through the anterior vertical incision. The remaining bony attachments of the anterior maxillary segment are severed with a narrow single bevelled osteotome along the floor of nasal cavity.

The segment is manually freed by covering it with a gauze sponge, and manipulated to get free of all attachments except palatal pedicle.

It is tried into the post operative site.  If any bony prominence interfering this can be removed.  Final positioning is done with the aid of an occlusal splint.  Before placement of splint the palatal tissue is closed with a horizontal mattress suture.

By this approach it is difficult to raise the maxilla and to setback posteriorly.

Wunderer’s technique

Wunderer (1962) developed his procedure to provide a palatally oriented approach to the sectioning and reposition of anterior maxillary segment.  Because of the segment is pedicled on labial mucoperiosteum it is possible to rotate it anteriorly for better visualisation of surgical site.  Here bony section may take place under direct vision. This is indicated if posterior movement is the dominant objective.

Technique

Vertical incisions are placed on the labial and buccal mucoperiosteum. Subperiosteal tunnelling is done and osteotomy is done through the vertical incision on the buccal and labial aspect.

On the palatal aspect an arcing incision is made through the palatal mucosa from the inter-dental space anterior to the site of the planned osteotomy cut. The mucoperiosteum is raised on to the posterior palatal side. The buccal osteotomy cuts are joined transpalatally under direct vision. Care is taken to prevent damage to the nasal floor mucosa.  If a midline split is required, it is fractured with a fine long bevelled osteotome.

The segment is freed completely by covering it with gauze sponge and with controlled manual force fracturing it from its remaining attachments.  The recipients site is contoured with a bur.  The mucoperiosteal flap is replaced with a horizontal mattress suture.  The segment is fixed with pre-fabricated splint.

Down fracture technique.

Cupar 1955 modified two stage procedure of anterior maxillary osteotomy into single stage down fracturing technique. This technique is mainly indicated if superior positioning is the dominant objective.  Epker described some advantage of this down fracture technique.

  1. – It is technically simple
  2. – Provides direct access to nasal crest of maxilla and associated nasal septal structures.
  3. – Permit removal of palatal bone under direct vision.
  4. – Gives excellent vascular pedicle.

The incision is made high in the labial vestibular mucosa at least 5mm above the root apices from premolar to premolar on the other side curving slightly in the midline towards the labial mucosa. Sometimes vertical incisions are placed anterior to the posterior osteotomy cuts.

The mucoperiosteum is raised to expose pyriform fossa, nasal septum, anterior nasal spine and the sub apical bone over the anterior tooth from premolar to premolar tooth.

The first premolars are extracted on both sides. The horizontal line of osteotomy is marked with bur starting from the pyriform rim up to the region of the extracted socket keeping at least 5mm above the root apices of the canine and incisors. The nasal mucosa is protected through out the procedure.  Then the osteotomy cut is turned vertically down to reach the alveolar margin by tunnelling approach or under direct vision when vertical incisions are used. Two vertical cuts are placed depending upon the amount of posterior setback. This buccal cortical bone is removed with a chisel.

After removing buccal bone the bur is directed to palatal bone in a semiblind  fashion. A finger is placed on palatal aspect to feel the cutting process and also to prevent  penetration of bur through the palatal mucosa is avoided.

The same procedure is repeated on the other side. Nasal mucosal floor is raised and the nasal septum is detached using a septal osteotome. The bone cut is completed on the palatal aspect with an osteotome by using gentle tap. Alternatively the palatal mucoperiosteum is raised and bur used to complete the cut  sometimes small midline vertical incisions are placed in the midline to gain access.

The segment is then down fractured and the bone is removed from palatal  aspect under direct vision.

The palatal mucoperiosteum is reflected slightly from the stable part (Posterior). This will allow easy movement of anterior segment posteriorly.

When superior positioning is planned the nasal spine is removed, the nasal floor in the mobilised segment is grooved to accommodate, the nasal septum,
or a segment of septum is sectioned from its anteroinferior part.

After the indicated amount of bone is removed the splint is inserted.  If the
correct position is not attained, the osteotomy site is re-examined and any
bony  projections are removed.

L shaped miniplates are used along the pyriform rim for fixation. Screws are placed at least 3mm away from root apices. Additional stability if needed can be achieved by wiring using a 26 gauge wire.

. During final positioning, care is taken not to crimp the palatal tissue between the segments as this would compromise the blood supply.

The wound toilet is done and the labial incision is closed in two layers. Any palatal or nasal floor tears are sutured with 3-0 vicryl. If alar base widening is significant then alar cinch suturing is done before mucosal closure.

Posterior Maxillary alveolar Osteotomy

Unilateral or bilateral posterior maxillary osteotomy or ostectomy provides a means of surgically correcting a wide variety of occlusal and dento alveolar deformities.  The relative indication of this procedure are.

(1)        To alter the transverse position of the posterior maxilla (to correct cross bite).

(2)        To superiorly position a supra erupted posterior segment.

(3)        To inferiorly position a posterior segment. (To close a posterior open bite).

(4)        To move a posterior segment forward to close an edentulous space.

Numerous technical approaches to the posterior maxillary osteotomy have been advocated.  Schuchart (1955) described a two stage method applicable to the closure of a posterior open bite.  In first stage the palatal bony cut is done and after 6 weeks the second stage, the buccal osteotomy, is performed.

Kufner (1968) modified this technique to a one stage procedure.  In this only buccal approach is done and palatal bone is divided through the osteotomy site by a thin osteotome as in case of down fracture technique.

West and Epker 1972 also described similar procedure.  Regardless of the technique utilised, principles of surgical reposition in this are similar to anterior segmental surgery.

The technique.

Access to the posterior segmental osteotomy is gained through a buccal sulcus incision extending from 1st molar to canine region.  Then  it is turned vertically down to marginal gingiva one tooth anterior to osteotomy site.  The muco periosteal flap is reflected to expose the lateral aspect of alveolar portion, lower part of zygomatic buttress and posteriorly to the pterygoid plates if needed.   If a tooth is planned to extract from the posterior end the mucosal reflection is limited to that region.

After bone is exposed the bony cut is marked by measuring with calliper and marks with pencil.  The bony cut should be at least 5mm above the root apices in order to preserve blood supply.

A predetermined amount of bone is removed from the buccal aspect (lateral maxillary wall) and the inter-dental alveolar osteotomy is then  completed from the buccal aspect.  Carefully expose the sinus mucosa and reflect it superiorly.  In cases of excessive supra-eruption of dento-alveolar segment the plane of osteotomy will be below the antral floor.

Now the palatal bone is divided.  It can be done using bur or osteotome.  In both cases a finger is placed as palatal mucosa to feel the instrument as it breaks the palatal bone.

If the osteotomy is extending posterior to 2nd molar, the level of bone cut is lowered posteriorly.  This will help easy separation or division of pterygoid plates.

If the osteotomy site at buccal aspect is small it will be difficult to cut the palatal  bone through this.  In such cases a palatal incision is placed anterior to the area of bone cut mucosa can be tunnelled and osteotomy can be done under direct vision.

The segment is down fractured with the osteotome placed in bone cut and lowered inferiorly.  A small curved osteotome is used to separate the pterygoid plates.  The bone removal is now completed.   If needed palatal mucoperiosteum can be reflected from stable part.  On posteromedial aspect of segment palatal neurovascular bundle can be identified.  Bone is removed carefully surrounding this and can be freed.

After the bone removal is completed the segment can be fixed with preformed acrylic splint.

Total maxillary osteotomies

Le Fort I Osteotomy.

Early effort to reposition the entire maxilla were directed at correcting traumatically malpositioned maxillary complex, and also to correct midface deformities secondary to cleft palate.  The danger of maxillary sinus infection and  fistulae as well as the possibility of necrosis of bony segment deterred, many surgeons from attempting this correction.

Wassmund (1927) performed this type of surgery to close a posterior openbite and in this after sectioning the lateral maxillary wall be used elastic traction to bring the maxilla down.  Axhausen (1935) was first to advance the lower portion of maxilla using this technique.  Schuchardt (1942) applied forward traction using a pulley and weight system to produce an advancement of sectioned maxillary segment.

Transection of pterygoid plate in Le Fort I maxillary osteotomy was described by Schuchardt 1942. Moore and Ward 1949 advocated the use of horizontal transection of the pterygoid for anterior advancement of maxilla.

Cupar and Rowe 1954 reported the use of bone grafting in Le-Fort I maxillary advancement.  Cerinac and associates (1955) and Cerinac in (1958) were also reported the use of bone grafts.

In 1959 Kole developed a two stage procedure for total maxillary osteotomy.  In the first stage he performed a U shaped palatal osteotomy anterior to greater palatine foramen and in second stage a labial bone cut is made.  Paul (1966) reported a similar procedure in a single stage. Obwegeser 1969 introduced a technique of wedging of bone graft between the pterygoid process and tuberosity for advancement of maxilla after surgery.

Dupont,  Ciaburo and Prevost 1974 advocated sectioning through the tuberosity rather than at the pterygomaxillary interface.  This modification was described by Trimble, Tideman and Stoleinga 1983.

Bell at al 1975 described down fracture technique of Le Fort I Osteotomy.  Epker and Wolford (1980) rectified this technique and described it in detail.  The advancement studies were done by Bell and Scheindermann (1981).  The associated changes in facial muscle was studied by Schendel (1983).  Luhr and Radney  1986 described the use of rigid fixation by miniplates in Le Fort I osteotomy.

Indications of Le Fort I Osteotomy

  1. Altering the vertical dimension of maxilla

–  Superior positioning in long face syndrome

–  Inferior positioning.

  1. Antroposterior movements of maxilla

In cleft palate patients & congenitally deficient maxilla

–  Maxillary advancement

–  Maxillary set back in maxillary prognathism

(only 3-5mm is possible)

  1. Levelling of occlusal plane in occlusal cant.
  2. Surgical expansion of maxilla
  3. Narrowing of maxilla.

TECHNIQUE

A horizontal vestibular incision is made from the mesial aspect of the maxillary first molar from one side to the other side about 5mm above the apices of the maxillary teeth. The incision can be made with blade or diathermy. The mucoperiosteum is reflected to expose the pyriform  aperture and lateral  wall of maxilla.  Posterior to zygomatic buttress the mucoperiosteum is tunnelled to expose the  tuberosity. The elevation of mucoperiosteum is extended to infra orbital   neurovascular  bundle. Nasal mucosa is reflected from lateral nasal wall, floor of the nasal cavity and from the lower  end of the nasal septum.

The osteotomy  line is marked on the bone over lateral  aspect.  It should be 5mm  above the apices of teeth, sloping down ward posteriorly. Vertical reference lines can be marked to access the anteroposterior movement of the mobilised segment. Osteotomy cuts are then completed with a flat fissure bur or with an oscillating saw. Bone division starts from lateral wall of pyriform aperture and taken posteriorly. Brisk oozing is sometimes noticed along the anterior maxillary wall.  For maxillary impaction the planned amount of bone is removed from the lateral maxillary walls of the maxilla after marking out two line anteriorly. Posteriorly these lines are merged or kept parallel depending upon the type of movement required. noticed Bone removal  should be done.  This gives a narrow, well controlled bone cut.  In case of superior  repositioning  the cut can be made with bur as  some  amount of bone  removal is  indicated.

The lateral wall of maxillary sinus is then divided.  A retractor is used to protect the buccal soft tissue.  This cut  is taken posteriorly to pterygomaxillary junction. Lateral wall of nose is divided below the  inferior turbinate with a  flat osteotome.  The cut is  directed  towards  the perpendicular plate of palatine bone which is partially divided.  Complete division may cause excessive bleeding from palatine vessels.

The nasal  septum is divided with a septal osteotome, along the floor of nasal cavity. The osteotome is hold  parallel to occlusal plane.  The endotracheal tube is protected now.  After all the walls are  divided , a curved osteotome is used to complete the bone cut at  pterygomaxillary junction. This is separated by gentle tapping . A finger is kept  posterior to pterygoid hamulus to feel the separation.

Maxilla is now down fractured by thumb placed over the alveolar bone.  As the down  fracturing progresses the nasal  mucosa is  reflected posteriorly.

Some times the separation may be achieved by disimpaction forceps or by use of special instruments like smith split spreader.

For   superior and  posterior  positioning elective bone removal is done with rounger or bur.  The removed  bone chips  can  be collected in saline  for filling the gap after fixation as autogenous  grafts.  This will speed up bone healing . Posterior repositioning with osteotomy of the pterygoid plates is difficult. Only 5 to 6 mm of posterior movement is possible. If excess movement is desired then a two piece maxillary osteotomy is to be planned or a maxillary tuberosity osteotomy is planned.

For maxillary advancement the bone graft is placed between the pterygoid process and maxillary tuberosity.  For this communication of pterygoid plates should be prevented during separation of pterygomaxillary junction.  Intact pterygoid plates will act as a posterior stop for bone grafts. some authors described a vertical step in the lateral cut in the region of the second premolar. This aids in measuring the movement and also to serve as stop for any bone graft that may be placed in the region.

In congenital maxillary hypoplasia a 3-5mm stable advancement is possible without placing bone grafts.

In cases of augmentation of vertical maxillary height the bone cut is made a higher level with respect to pyriform aperture.  This is to get 5mm of bone in sub apical region after the osteotomy of lateral and medial walls.  The maxilla is advanced and lowered using rows disimpaction forceps.  The beaks are applied below the nasal mucosa and gentle rocking of the maxilla will help to relieve soft tissue resistance to anterior traction.  After adequate inferior traction bone grafts 9 split thickness calvarial grafts ) are fixed in position.

Segmentalization of the Le Fort I segment can be done if necessary, taking care to preserve the vascular pedicle. The common segmentalization procedure include:

  1. Anterior maxillary osteotomy
  2. Sagittal midline osteotomy.

The anterior maxillary osteotomy is combined with Le fort I impaction in patients who have vertical maxillary excess with dento-alveolar protrusion of moderate to severe degree. The osteotomy is usually carried out through the socket of the extracted 1st or 2nd premolar. The bone cuts are made through tunnelling of the mucoperiosteum for access. Care is taken to preserve the pedicles.

Alterations in transverse dimension if required can be performed after down fracture. In cases requiring expansion a mid palatal split is done using a fissure bur.  The palatal muco periosteum is protected while doing this.  After bone division the Mucoperiosteum is reflected through the  osteotomy gap and extended to vertical alveolar portion.  Should not damage the palatal vessels.  Up to 6mm of expansion is possible without bone grafting.  If excessive expansion is done the stretching of palatal mucosa may lead to ischaemia and necrosis of bone as well as soft tissue.  If the bone gap is more than 6mm partial thickness parietal bone graft should be fixed in this gap.

In case of narrowing of maxilla the alveolus should be divided in midline before down fracturing and then the down-fracturing is done and the division of palatal midline is done posteriorly.  The mucoperiosteum is reflected from the edge of osteotomy and adequate bone is removed from midline.  Then by pushing the mucoperiosteum into oral cavity  the segments can be fixed together with inter osseous wiring.  Alterations of occlusal plane may be required in some cases.  Oblique occlusal plane can occur in patients with unilateral condylar hypo/ hyperplasia, hemifacial microstomia, Romberg syndrome etc.  The assessment of this defect should done by clinical examination and evaluating PA cephalogram.  This condition is treated by.

–  Increasing vertical Ht. of maxilla on one side.

–  Decreasing vertical height on  one side.

–  or a combination

A combined form of treatment is often more practical because of concomitant soft tissue changes.  Hence the height is increased slightly on side of deficit and decreased on side of excess.  This should be accompanied by mandibular surgeries to attain complete occlusion.  For levelling of occlusal plane the maxilla is released in Le Fort I plane.  The excessive bone is removed from one side. The other side is augmented by bone graft. Corticocancellous grafts from iliac crest is ideal if excessive alteration is required.

Fixation

After the required corrections, the maxilla should be fixed to the basal bone. Historically, the mobilised maxilla was fixed directly to the pyriform rims and zygomatic buttress with transosseous wires or suspension wires placed at the zygomatic buttress, the zygoma or in the infra orbital rim.

In cases of transverse corrections a prefabricated acrylic splint should be placed to get three dimensional stability of the occlusal plane.  In other cases a temporary inter maxillary fixation should be done.  During this it should be ascertained that the condyle of mandible is in glenoid fossa.  After the IMF is done the segment is fixed superiorly.

In cases of superior and backward positioning a circum zygomatic suspension can be done.  This gives a postero-superior force.  The wires are tightened simultaneously on both sides.

In maxillary advancement without  inferior positioning a infra orbital rim suspension is recommended.  This gives a upward and anterior vector of force.

The inferior positioning is difficult to fix by these methods.  Wiring at lateral pyriform border can be done.  Simultaneous wiring of bone graft also to be done.

Instability of the maxillary repositioning has been noted and these have been attributed to various factors. These include

  1. Inadequate bone stabilisation
  2. Poor bone contact.
  3. Excessive superior repositioning or superior relapse of an inferiorly placed maxilla may be due to the mandibular occluding forces as the masticatory muscles contract.
  4. Maxillary advancement is also plagued by relapse, especially following large forward movements or due to excessive soft tissue restriction after multiple or cleft surgeries.

To overcome these problems more rigid forms of fixation are devised. These include rigid adjustable fixation and rigid internal fixation.

Rigid adjustable fixation for maxillary osteotomy

These uses mainly pins and wires to secure the maxilla. Various forms of rigid adjustable devices had been advocated. Bays 1985 suggested the use of 2.7 mm screws in the superior segment. Pins are attached to the arch wire. Then  0.045 inch orthodontic wire is used to stabilise the maxilla to the screws and pins. This can be adjusted postoperatively for minor adjustment in maxillary position.

Bennett & Wolford 1985 suggested another system where in they used 2mm Steinmann pin into the  zygomatic buttress area. They secured it to the arch wire using acrylic. They obtained anterior stabilisation by rigid internal fixation by means of miniplates.

These pins can be removed after healing by local anaesthesia and intravenous sedation.

Internal rigid fixation for maxillary osteotomy.

Rigid fixation with screws and plates gives satisfactory stable fixation in all forms of osteotomy.  This is especially important in inferior positioning of maxilla which is least stable when other forms of fixation are used.  Simultaneous fixation of bone grafts also can be achieved with rigid fixation.  This will improve the graft viability.  In Le Fort I osteotomy the areas suitable for rigid fixation are zygomatic buttress and pyriform margins.  These areas having adequate bone thickness of insertion of screws.  After the planned post operative position is achieved and temporarily IMF performed straight, L shaped or T shaped plates suitable for 2mm screws are passively adapted in these areas.  Improper adaptation will lead to alteration of occlusion later.  The holes should be perpendicular to surface in-order to achieve maximum bone thickness for screws.

Ian Munro (1989) recommended at least 4 plates should be used for Le-Fort I osteotomy.  Two at zygomatic buttresses, two at lateral pyriform margins.  Each plates should have 4 holes minimum 2mm monocortical self tapping screws are widely accepted.

McCarthy (1990) recommended that if rigid fixation is planned the osteotomy should be done at a higher level in order to get adequate bone at sub apical region for placement of screws without endangering root apices.

Stella & Epker 1994 advocated semirigid fixation with posterior zygomatic buttress wiring and anterior plates in the pyriform rim. The posterior zygomatic buttress wiring can be adjusted depending on the occlusal needs of the patient.

Wound closure & Soft tissue considerations.

After satisfactory fixation the area is irrigated inspected for loose bony fragments, and any other foreign bodies.  Closure of the incision line can be done in two layers.  Before that any mucosal tear should be sutured with 4 ‘0’ catgut.  This will reduce the chance of post operative nasal bleeding.

Widening of alar base is a frequent complication of superior positioning of maxilla.  This can be prevented by a traction suture ( alar cinch suturing ) with a non observable material across the alar base. Gahli & Sinn 1997 advocated Weir procedure or a simple lateral nostril sill excision with undermining and re-approximation  for management of increased alar base width. Other authors have advocated the use of secondary rhinoplasty techniques for management of the alar basal width problems. Kawanato (1989)  recommended  separation of  anterior  nasal spine  from maxilla along  with nasal septum.  This  will retain the soft tissue  contour at the nasal  base.

The upper lip length and vermilion exposure changes drastically with Le fort I osteotomy. Lip length reduces by 20 % of the planned bone movement in a Le fort I  impaction with reduction in vermilion exposure. V- Y closure of the mucosa with a vertical limb of 10 –15 mm maintains the pre-operative vermilion exposure and lip length. A vertical limb of 15 – 25 mm increases lip length by about 1 –2 mm and also increases vermilion exposure. Appropriate use of these closure method is indicated depending upon the treatment plan.

Total Maxillary alveolar Osteotomy (TMAO) (Hall and Roddy 1975)

Total maxillary alveolar osteotomy was described by Paul 1969 based on the experiences of Kole & Mohnac. Hall & Roddy 1975, West and McNeil 1975, Hall and west (1975) , West & Epker 1972 also published this as a treatment for total maxillary  alveolar hyperplasia.  Meloney et al (1982) reviewed few cases of this and concluded that TMAO is a “good technique in his time”

Sterling R. Schow  (1986) described few advantages

(1)        It can be used to intrude maxilla for hyper plastic maxillary alveolus, to correct posterior or total alveolar hyperplasia with or without anterior open bite.  This is particularly useful when impaction of the segment is more than 5mm.

(2)        It is a substitute for Le Fort I surgery when there is long alveolar  process with  high arched palate.

(3)        The reduction of sinus volume and possibility of air way constriction is avoided  with TMAO.

(4)        Even in absence of vertical excess, this can be used to expand, constrict or recontour the alveolar arches.  In such cases it provides a stable palatal base to which the segments can be fixed.

(5)        It is less suitable for inferior positioning or advancement.

Epker and Wolford 1980 described this technique as “superior positioning of maxilla with nasal floor intact”.  They gave the indications for this procedure.

(1)        When superior movements 10-15mm is required.

(2)        In pre-existing decreased nasal airway function not related to nasal septal deviation (DNS) or large inferior turbinate.

(3)        when segmentalisation of maxilla is required in 3 or 4 segments.

Technique.

This may be accomplished with surgical access obtained through a horizontal mucoperiosteal incision near the depth of the labial vestibule similar to that of Le fort I down fracture technique or through multiple vertical incisions with tunnelling beneath the alveolar mucosa and palatal access through incision and elevation of a palatal “horseshoe” mucoperiosteal flap.

A circum-vestibular incision is made which extend from one Zygomatico alveolar crest to the other.  Posterior to that the soft tissue is undermined to the pterygomaxillary junction.

The alveolar portion and lateral maxillary wall is exposed by minimum but adequate elevation of mucoperiosteal flap is done.

The nasal epithelium is elevated starting from pyriform aperture to 10-15mm posteriorly, and also from the anterior floor of nasal cavity and inferior portion of septal cartilage.

By protecting the nasal mucosa with a retractor the horizontal osteotomy through the lateral maxillary wall is made extending from the nasal cavity to the pterygomaxillary junction. The anterior 10 to 15 mm of lateral nasal wall is also transected. If superior impaction is planned, the inferior osteotomy is completed 4 to 5 mm above the apices of the tooth and this is followed by a superior osteotomy to remove the measured amount of bone. Posteriorly the osteotomy is directed towards the pterygomaxillary junction or to the third molar extracted site which has been removed 4 to 6 weeks prior to surgery.

If the dentoalveolar segment  is to be divided into multiple segments, the mucoperiosteum overlying the alveolus at the site of osteotomy is tunnelled and the osteotomy cut performed. The palatal bone at the vertical osteotomy site is cut  taking care to prevent damage to the palatal periosteum.

A ‘V’ shaped groove is cut from the anterior nasal floor in the midline after separating the nasal septum from floor of nasal cavity.  This should be 4mm away from root apex of central incisor.  This is to accommodate the nasal septum during superior positioning of maxilla.  If this clearance is not possible the anteroinferior portion of septum should be sectioned.

The palatal bone cuts are made. In the anterior region if there is large amount of bone in the alveolar segment then bone cuts are made inferior to the floor of the nasal cavity. With a small osteotome or a fissure bur a transnasal osteotomy is completed from right to left across the palate approximately 10 to 15 mm into the nasal cavity. A palpating finger  is placed on the palatal side to avoid damage to the palatal mucosa. Laterally the bone cuts extends into maxillary sinuses. Posteriorly the osteotomy cuts extends along the medial wall of the maxillary sinus below the level of the nasal floor into the oral cavity.

Two osteotomes are inserted in the osteotomy gap and is levered down wards to down fracture the maxilla.  If it fails a curved osteotome is used to remove palatal bone posteriorly.  This should be carefully done.

If the 3rd molar is to be removed either due to impaction or any other causes it can be done at this time.  If so the osteotomy can be limited to 3rd molar socket.  Or the pterygomaxillary junction can be disrupted by gentle tapping with osteotome.

After down fracture adequate bone is removed from palatal side and the segment can be moved to its pre-planned position.

The palatal mucoperiosteum can be undermined carefully from the fixed part.  This will help in easy positioning of the segments.

The mobilised segments are now repositioned by selective bone removal and the planned  postoperative position is attained.

The fixation can be done by a prefabricated occlusal splint made from mock surgery on study model.  Or the fixation can be done with orthodontic appliance.  A temporary inter maxillary fixation is performed to ascertain the anteroposterior relation.  The segment is now fixed superiorly. In cases of superior and posterior placement, a circum-zygomatic suspension can be used.  If the repositioning is in a superior and anterior direction suspension to infra orbital rim can be done.

Alternatively a lateral pyriform rim wiring can also be used.  Now the temporary inter maxillary fixation is removed and the wound is closed.

Some modifications are suggested to this standard technique.

Bell 1975 used the same incision as in Le-Fort I Osteotomy.

Bell, West (1975) West and Roddy 1976 and McNeil on (1975) described a combined palatal and labial approach.  In this on the labial aspect 3 vertical incisions are used one in midline, other in premolar region on both sides.  Through this sub mucosal tunnelling is done and osteotomy is performed on buccal and labial aspect. After the buccal osteotomy is completed a palatal mucoperiosteal flap is raised.  For this a U shaped incision is put about 1cm apical to gingival margin starting from one 2nd molar region lateral to the greater palatine vessels.  It is brought anteriorly just lateral to greater palatine vessels, Anteriorly is turned to opposite site just palatal to incisive papilla, and extend to other 2nd molar. A full thickness mucoperiosteal flap is raised.  Now the palatal bony cut is done directly, dividing the palatal wall of maxillary sinus and anterior nasal wall.  Posterior to the greater palatine foramen the bone may fractured or divided with osteotome. After adequate bone is removed the segment can be fractured using digital pressure or by levering instruments.  Selective bone removal is done and the segment is  repositioned and fixed.  This technique has advantage of direct access to the palatal bone and is suitable in cases of thick palate.  But the palatal vascular pedicle is compromised.

All the authors suggested that if there is adequate bone in sub apical region and below the nasal and antral floor, the osteotomy should be done at this plane without entering the nasal and antral floors for impacting the maxilla.

Quadrangular Le Fort I osteotomy.

Hugo Obwegesser 1969 described a high Le fort I osteotomy for correction of midfacial hypoplasia in cleft lip and palate patients. This was named Quadrangular Le Fort I osteotomy by Keller & Sather 1989, because of the indications, osteotomy shape and level and projected clinical outcome were quite similar to those of the quadrangular Le fort II osteotomy as described by Kufner. Here the advancement of both the infra orbital rim and a portion of the zygomatic complex is done.

Indications

This is mainly indicated in patients with maxillary-zygomatic horizontal deficiency, with class III skeletal malocclusion and normal nasal projection. This is ideal in management of midface hypoplasia with midline problems or transverse deficiency.

Procedure

The procedure is done intraorally through the down fracture approach of Le Fort I osteotomy by a horizontal vestibular incision. The entire surface of the anterior maxilla is exposed by subperiosteal dissection extending from the right to left tuberosity and up to the infra orbital rim. The infra orbital nerve is isolated and the orbital rim periosteum is reflected. The mucosa over the floor of the nose is exposed and also from the lateral nasal wall.

The osteotomy cuts are placed on the lateral wall of maxilla from the pyriform aperture at the level of the infra orbital nerve. The osteotomy is extended laterally below the level of the infra orbital nerve to the tuberosity and pterygoid plate region. The maxilla is down fractured after detaching the nasal septum, pterygomaxillary disjunction and ostectomising the lateral nasal wall.

Bone grafts are used in the infra orbital region and also in the pterygomaxillary junction.

Le Fort II Osteotomy

Converse 1971 described an osteotomy for correction of the nasomaxillary hypoplasia. This was classified as  “Anterior Le Fort II osteotomy” by Steinhäuser 1980. Henderson and Jackson (1973) described classical Le Fort II Osteotomy for patients with naso maxillary and midface hypoplasia. This was classified as “Pyramidal Le Fort II osteotomy” by Steinhauser. Kufner (1971) described an osteotomy for correction of nasal hypoplasia and also for the infra orbital region. Similar osteotomies were described by Souriyas et al 1973and Champy 1980. This was classified as “Quadrangular Le Fort II osteotomy by Steinhauser. Epker and Wolford in 1980 given a detailed description of standard Le Fort II Osteotomy.

Anterior Le Fort II osteotomy. (Naso-Orbito-maxillary osteotomy).

It is  an initial form of Le Fort II osteotomy described by converse and associates (1971).  Used to correct the nasal and maxillary deficiency.  The principles of these procedure are:

–           The foreshortened nasal septal frame work must be advanced as it will oppose
nasal lengthening.

–           A forward and downward placement of nasal and maxillary complex is required to correct midface deficiency.

–           The naso lacrimal apparatus must not be disturbed.

–           Bone grafts should be used to restore the Bone deficiencies.

–           Skin coverage and nasal lining must be provided to accommodate the nasal
elongation.

The upper part  of this osteotomy done, through a V shaped incision with the apex at glabella and extended bilaterally along both sides of nose to reach just above the alar base.  The cartilaginous and bony part of nose is separated and the columella is pulled down.

Osteotomy begins at lower end of nasal bone directed medially to the medial wall of orbit than downward to reach the floor of orbit posterior to naso lacrimal apparatus.  Then it is brought to infra orbital margin medial to the nerve and extended downwards to the alveolar bone posterior to 1st premolar.  Then a posteriorly based palatal flap is raised and 5/5 are extracted the osteotomy is completed through the sockets of this dividing hard palate.  Now the segment is mobilised and advanced.  This can be fixed by a prefabricated acrylic splint.

This Procedure:

–           Lengthens the nose

–           Nasal tip moved anteriorly and downwards.

Advances anterior maxillary segment.

This technique was modified by Psillakis & Co worker 1973 by taking a transverse osteotomy above the apices of anterior teeth and augmenting the nasomaxillary segment. This is not biologically sound so this technique is hardly used nowadays.

Pyramidal Le Fort II osteotomy.( Classical Le Fort II )

This is indicated in Naso maxillary abnormalities such as.

–  Binders syndrome

–  Crouzon’s Syndrome

–  Apert’s syndrome

–  Extreme Cleft palate cases

–  Midface deficiency with short nose and class III Occlusion.

This osteotomy is performed through a coronal incision, a bilateral lateral nasal incision and an intraoral upper vestibular incision.

After subperiosteal elevation of flap the lateral aspect of nasal bone, medial canthal ligament and lacrimal apparatus are identified.  Osteotomy begins just below the frontonasal suture and extended posteriorly, then downwards anterior to attachment of canthal ligament.

Then behind or anterior to nasolacrimal opening to reach the floor of orbit. The osteotomy is brought anteriorly to reach the infraorbital margin.  It is divided at  planned position and then proceed on anterior wall of maxilla, posteroinferiorly to infraorbital foramen.  Now through the intraoral sulcus incision the osteotomy proceed below the zygomatic buttress as in Le-Fort I Osteotomy.  The procedure is repeated on opposite side of using a curved osteotome the maxilla is separated from skull base at naso ethmoid region. The nasal septum is separated using a nasal septal osteotome in a posterior and downward direction. Now using Row’s forceps to maxilla is rocked and advanced.

Bone grafting are done at the infra orbital region.

Quadrangular Le Fort II Osteotomy

Kufner1971 described an osteotomy which was in essence a combination of Le fort I and Le Fort II osteotomy. This was modified by Stoleinga & Brouns in 1996.

The osteotomy starts from upper part of pyriform aperture to reach the floor of orbit medial to infraorbital  foramen.  Then another osteotomy starting from tuberosity extended along the zygomatic buttress to reach the infra orbital rim lateral to foramen.  These are connected in the floor or orbit.  Thus a U shaped osteotomy separates maxilla without disturbing nasal base.  It is indicated in patients with prominent nose with paranasal deficiency.

After advancing maxilla fixation is done similar to Le Fort I.  If there is severe nasal hypoplasia augmentation of nose is done with calvarial bone graft and soft tissue augmented by a V-Y procedure.

Stoleinga & Brouns 1996 advocated a modification in which the osteotomy cut goes around and below the infra orbital foramen to prevent damage to the nerve.

Le Fort III  Osteotomy

This  osteotomy more or less follows the classic Le Fort III fracture line.  It is mainly used for advancing  deficient midface.  Midface deficiency can affect maxilla, zygoma and nasoethmoid complex either individually or in various combination. Accordingly the surgical plane must be altered.  Le Fort III is indicated in a combined maxillary, zygomatic and nasal deficiency.  In case of normal nasal projection and maxillary and zygomatic deficiency a modified maxillary malar osteotomy is suggested.

The access for Le Fort III osteotomy can be achieved through a bicoronal incision, Transconjunctival incision, Glabellar, or sub Ciliary incisions and through an intra oral upper buccal sulcus incisions.

After reflecting a bicroronal flap the fronto nasoethmoidal region, lateral orbital rims, are exposed.  The infraorbital rim and orbital floor are then exposed through  a subciliary incision.

The infratemporal space is exposed by reflecting temporalis inferiorly.  The medial canthal tendon are detached and tucked with suture.

Osteotomy begins just below the fronto nasal suture and passed medialy to divide ethmoid bone and through the medial wall of orbit it enters the orbital floor.  The  infraorbital neurovascular bundle is dissected out of bone and osteotomy is continued laterally to reach in the inferior orbital fissure.  Now the lateral orbital wall is exposed  and osteotomy begins at area of deficiency.  This is connected to the anterior end of inferior orbital fissure.  Now  the pterygomaxillary junction is exposed through intraoral incision.  Using chisel pterygoid plate is separated from maxilla.  This is extended superiorly to inferior orbital fissure.  The nasal septum is separated through the osteotomy site is the frontal region.  The cut passes through perpendicular plate of ethmoid and vomer.  At this level bleeding is less and chance of damage to olfactory fibres are less.

Mobilisation of maxillary malar complex is now done by using disimpaction forceps.  By gentle rocking movements the segment is gradually moved to the required position.

Bone grafts are placed at lateral orbital rim and glabellar region and secured with wires.  Onlay grafts are also placed for augmenting the infraorbital rim, frontal area etc; Medial canthal ligaments are replaced by non absorbable suture in a figure of 8 manner.  Miniplates are applied at frontozygomatic osteotomy site, the fronto nasal osteotomy, and between zygomatic arch and zygoma.  Before placing the miniplates inter maxillary fixation is applied in a slightly over corrected position.  After rigid fixation this is removed.  The bicoronal flap is now closed 2-3 suction drains are applied.

Malar maxillary advancement

It is modified Le Fort III osteotomy.  It is indicated for individuals with malar and maxillary deficiency with normal bone projection.  In this the osteotomy begins at medial end of inferior orbital rim just lateral to lacrimal apparatus. It is connected to pyriform aperture. Along the floor of orbit, without making injury to inferior neurovascular bundle the osteotomy proceed to lateral orbital wall just below the whitnal’s tubercle the lateral orbital wall is divided.  Then osteotomy extended lateral orbital wall is divided.  Then osteotomy ex tended lateral to zygomatic eminence in an oblique manner brought anteriorly to the inferior border root of zygomatic arch.  Now through an incision in posterior aspect of upper buccal sulcus the lateral wall of sinus and pterygoid plates are divided as in Le Fort I surgery.

Now through anterior sulcus incision the nasal  cavity is exposed and the nasal septum is detached.  This and  division of lateral nasal  wall is done as in Le Fort I surgery. Now the segment can be  advanced with forceps,  slight over  correction is done and fixation  is done  at fronto zygomatic and lateral pyriform  rim regions.

Complications of maxillary orthognathic surgeries

Maxillary surgery produces relatively few complications when the operative procedure is well conceived, carefully planned and precisely executed. The majority of the problems that do occur result directly or indirectly from careless and inadequate planning.

Incorrect line of fracture

Incorrect line of fracture usually occurs during pterygomaxillary disjunction and also during down fracture.

The ideal fracture that separates the pterygoid and the tuberosity should do without damage to the  either parts. Improperly directed force would result in fracture of superior part of maxillary sinus, a high horizontal fracture of pterygoid plates or a damage to pterygoid canal can occur. Directing the force with a small osteotome from the posterolateral to antromedial aspect would result in a more predictable cut. If the pterygoid plates is fractured in which advancement is planned, mechanical support by means of bone grafting at the pterygomaxillary junction will offset the incorrect fracture and prevent postoperative relapse.

 Hemorrhage:

Bleeding can be  a  major  concern in maxillary surgeries.  During surgery blood vessels  most commonly encountered are  greater palatine artery.  internal  maxillary, nasoethmoidal vessels, posterior  superior alveolar artery and pterygoid venous  plexus.  It is  generally  recommended that hypotensive  anaesthesia should be used  for midface osteotomies. Richard Ellis et al 1990  reviewed cases of life threatening post-operative  bleeding after Le Fort I  osteotomy.  In most occasions descending palatal artery was the source of bleeding and in some case the internal  maxillary  artery.  Pressure packing with a  posterior nasal pack,  ligation of upper part of  external  carotid  artery and  selective embolisation technique were used.  Closure of tear  of nasal  mucosa before wound closure will reduce postoperative epistaxis.

Infection

Increased  chance of  infection in midface  surgery is due to communication to nasal  and oral  cavities. Behrman (1972) reported only 3cases of infection out of 600 maxillary  osteotomies. A double blind study of Eschelman 1986 showed a significant reduction of infection with antibiotic prophylaxis .Obviously good surgical technique good closure of soft tissue incisions and maintenance of good vascular supply will help to minimise the infection  McCarthy and Converse 1972 questioned routine use of antibiotic prophylaxis. They listed some of the indications for prophylactic antibiotics in orthognathic surgery.

–           An intraoral surgical approach

–           Previous irradiation of operative sit

–           Use of bone grafts

–           Use of alloplastic implants

–           Poor oral hygiene

–           Patient prone to  infection.

Oedema

Excessive oedema is common in midface surgeries.  It is  disappointing  to the patient.  It is due to  laxity  of subcutaneous tissue of midface.  Shelton and  Irby (1980)  recommended use of steroids in initial post operative period.  They used dexamethasone sodium 8-10 mg.    6th hourly, first dose being started at operating room.  This  is continued for 48  hourly and following this methyl prednisolone acetate 80 mg. is given for next 2 days.

Loss of  Segment:

Decreased  blood flow may lead  to loss of segment and delayed union. This can occur in segmental surgeries.  This is due to improper vascular pedicle and subsequent ischemic necrosis. In case of retained buccal mucosal  pedicle this complication is rare when compared to total sulcus  incision.  The damage to  palatal mucosa during   palatal  bony cut is  common cause of this.  Use of ill fitting splints which causes excessive pressure can cause ischaemia.  Avascular necrosis will lead to gingival  infection, gingival recession, loss of  alveolar bone, loss of  teeth  and total  loss of segment.

If ischemic necrosis occurs-

–           Keep good oral hygiene.

–           Prophylactic antibiotics to be given.

–           Retain teeth as much as  possible.  Some bone may revascularise later..

Epker  1984  recommended the following steps to avoid ischaemic necrosis

  1. Avoid transection  of greater palatine vessels.
  2. Stretch (as opposed to tear) the soft tissue  during mobilisation of maxilla.

3          Make  appropriate  palatal soft tissue relaxing  incisions  for simultaneous expansion.

  1. Consider a vertical vestibular  incision in  potentially troublesome cases.

Relapse:

Relapse can occur at various stages of orthognathic surgery.  It can be immediate or short term relapse or long term (delayed) relapse.

Short term relapse can occur during fixation by I.M.F.  If the fixation of osteotomised segment is not stable and IMF is done  after the fixation of surgical segment this can occur.  IMF should be done before fixing at osteotomy site.  Relapse mostly seen with interosseous wiring.  If maxillary walls are very thin the relapse is more.  This should identified at time of surgery and adequate bone grafts should be placed.

Long term relapse is mainly due to soft tissue traction mainly seen in advancement cases.  Anterior  and inferior  advancement showing more relapse, maxillary expansion, if exceeds more than 6-7 mm, shown high relapse.  The Superior placement of maxilla is  reported to be more stable.  Among segmental surgery posterior subapical advancement for closure of posterior openbite shown excessive relapse tendency.

Will man (1970) studied 106 cases of maxillary Le Fort I advancement.  He  found stable  results  for 3 years – 1 mm  posterior movement noted in first year and   the superior  movement was 1.8 – 2.8 mm. in first year.  More relapse was noted in male patients.

Tessier  and Shiter (1982) also reported a similar study.  In his study bone was stable  after 1 year, and upper lip lost 44% of its advanced position.

Carloti and Scheudel (1987)  Oaus worth 1984 where studied the osteotomy site histologically.  They showed healing of the site with impact bone.

Ward Booth, Bhatia and Moose (1984) showed a relapse of more than 30% in       Le-Forte II advancement.  In a study normal patients  (without cleft palate) Batton and Moose showed  little evidence of  relapse with Le Forte II Advancement.

Nerve injury

The injury to infra orbital nerve is seen in high Le Fort I, Le Fort II and III osteotomy. Damage to the nerve occurs during manipulation of incision, bone cutting and anterior repositioning of the maxillary segment.

Loss of tooth vitality and sensitivity.

Vitality of tooth is maintained by the blood supply where as sensitivity by the nerve supply.  When the blood supply is lost pulp becomes necrotic and discoloration of tooth and periapical changes begins.   But in cases of loss of nerve supply alone the vascularity is maintained and tooth will be vital.  However some fibrosis and calcifications will result.  Bell et  al (1969) in an animal study shown that if the apical bony cut is done 0.5 cm or above the apex and any of one flap (palatal lingual or buccal) is retained to the segment both vitality and sensitivity will be remaining.  They demonstrated neural and  vascular plexus connecting this flaps with apical  vessels and nerves.  D. Poss Willo (1972)  demonstrated progressive loss of  odontoblasts  in teeth of osteotomised segment.  Banks (1978) in an animal study demonstrated progressive  fibrosis and calcification in teeth involving osteotomised segment.  But these teeth remain vital even after 52 weeks postoperatively.  Pulpal changes also reported by Hutchinson and  McGregor, Kart and Hinds (1971)  in 4 years.  Following -up  study of 25 patients with segmental osteotomy reported that 1-15 mm periodontal bone loss occurring in one year after surgery.  Less bone loss is seen in younger individuals.  Maximum retention of flap over segment showed better results.

Perpesack (1973) reported 94-95% of teeth regained sensitivity after 12 months in maxilla and 72% in mandible.   McArthur and Turvey (1978)  reported 2% loss of sensitivity,  Kanberge and Ergstorm (1988) reported loss of sensitivity in 90% teeth following Le Fort I Osteotomy.  After 18 months all of these regained sensibility.

Mohd El Dep (1984) recommended following precautions to avoid damage to root and periodontal structures.

  1. Avoid multiple  segmentalisation if  orthodontic  alignment is possible.
  2. Avoid segmentalisation if there is in adequate interdental
  3. Start interdental osteotomy  with bur and finish  with osteotome to reduce
    injury to lamina dura.

Oroantral and oronasal fistula

This usually follows a tear in palatal mucosa  and in nasal mucosa. This occurs mainly in maxillary expansion with mid palatal procedures.  Careful  soft tissue handling will  minimise the complication .  If such a  communication does occur, the tissue is allowed   to mature  for 6-9 months ,   during this time  defect can be covered with acrylic splints.  Later closure using local flap can be considered.

Velopharyngeal incompetence

It is  a rare complication can  occur in patients with corrected cleft palate.  This is caused by excessive anterior traction of soft palate in maxillary advancements.  Pre-operative assessment can avoid such a problem.

Other rare complications

These include ophthalmic complications, vascular complications and avulsion of a segment.

Vascular complications.

 

Ophthalmic Complications

This is a rare complication after Le fort I osteotomy this occurs mainly during pterygomaxillary disjunction. The ophthalmic complications of orthognathic surgery may be divided into 3 categories

  1. Lacrimal system – Injury to the lacrimal system may lead to inability to tear or epiphora. The epiphora is usually transient and is due to surgical oedema.
  2. Diplopia – This is due to abducens neuropraxia / paralysis secondary to propagation of pterygomaxillary disjunction fracture. The diplopia usually resolves in course of time.
  3. Visual loss – This is an extremely rare complication.

CURRENT CONCEPT IN ORTHOGNATHIC SURGERY OF MAXILLA

Now the principle of distraction osteogenesis have been used for the advancement of maxilla in midface hypoplasia patients. After performing the osteotomy the maxillary segment is suspended to the zygomatic arch based distractor or to a halo frame fixed around the head. The maxilla is distracted slowly at the rate of 1mm per day. About 10 to 15 mm advancement is feasible by this process. The relapse tendency is minimal by this procedure. This distraction osteogenesis represents the new advances in bone regeneration and the fourth generation of grafting  techniques in craniofacial surgery.

In the study conducted by Hans Peter .M. in Reversing segmental osteotomies of the upper jaw, mainly on patients which had undergone upper anterior segmental surgery 6 months to 10 year back.  Most of the these patient came back with remark that they looked unduly aged because the lower part of the face was dished in. Author discussed the complications of the reverse osteotomies and in order to restore the old situation a new treatment plan is to be made.

In the study by M. R. Reinkingh, for the transverse stability of the Le Fort I Osteotomies a palatal surgical splint is made of a transpalatal stainless steel bar with acrylic abutment against the palatal surface of the molar and bicuspid tooth.  It is rigid and renders excellent retention. It causes minimal patient discomfort, and oral hygiene is hardly compromised.

A study conducted by A. Stewar, A.M. M. Cance,  D. R. James, J.P. Moss on three-dimensional nasal changes following maxillary advancement in cleft patients.  Three dimensional laser surface, scanning of the face was performed before and after Le Fort I maxillary advancement in 24 patients with repaired clefts of the lip and palate.  The surgery resulted in advancement of the upper lip and para-alar tissues and an increase in the relative prominence of the nose. These changes were produced at the expense of an increase in nasal width and a reduction in nasal tip protrusion.  The changes is nasal morphology showed significant variation among patients.

In the study conducted by D. Bloomquist, D Baab, Y .B. Geylikman, J. Artun, B. G. Leroux evaluated the  effect of  Le Fort I  osteotomy on human gingival and pulpal circulation.  The maxillary blood flow during the first 24 and following Le fort I osteotomy was evaluated by Laser Doppler flowmetry.  Pulpal blood flow was recorded from two maxillary incisors and gingival blood flow was assessed from a site slightly apical to the interdental papilla of the maxillary central incisors of 12 patients receiving Le Fort I osteotomy, nine control patients receiving mandibular osteotomy, and 10 non surgical control subjects with out orthodontic appliances.  Measurements were made before surgery and at time intervals between 0-8, 8-16 and 16-24 hrs after surgery following surgery, men gingival (but not pulpal) blood flow significantly lower for patients treated with Le Fort-I osteotomy.

 

CONCLUSION

Orthognathic surgery has made it possible to reposition of either or both jaws in all possible directions.  This has provided solution for the patients with  severe dentofacial problems and malocclusion. Thorough evaluation and assessment of the defect and efficient execution of the surgery is needed for effective result.  Use of more rectified technique, improvements in instruments especially the introduction of the fine oscillating and reciprocating saws has enabled the surgeon to precise. The development of new techniques like distraction osteogenesis have aided in reducing relapse after an maxillary advancement and the need for extensive surgery. Repeated assessment and rectification of the technique are required to improve the outcome of these aesthetic surgical procedures.

 

REFERENCES

  1. The quadrangular osteotomy revisited. Paul J W Stoleinga & John J A Brouns. Journal of Cranio – Maxillofacial surgery. 2000 : 28 : 79 – 84.
  2. Maxillary osteotomies. R. Gunaseelan. Indian journal of Oral & Maxillofacial surgery. 1998 : VIII : 9 – 14.
  3. Blindness as a Complication of Le Fort Osteotomies : Role of Atypical Fracture Patterns and Distortion of the Optic Canal. John A. Girotto, Jack Davidson, Michael Wheatly, Rick Redett, Tom Muehlberger, Bradley Robertson, James Zinreich, Nicholas Iliff, Neil Miller, Paul N. Manson. Plastic and Reconstructive Surgery, Oct 1998; Vol. 102; No 5; 1409 – 1423.
  4. The long-term unfavourable result in orthognathic surgery I : Mandibular, Maxillary and Combined deformities. Douglas P. Sinn & G. E. Ghali. Complications in Oral and Maxillofacial surgery. Leonard B. Kaban, M. ANthony Pogrel & David H. Perrott. W. B. Saunders company. 1997. 255 – 264.
  5. Maxillary Orthognathic surgery. Robert A. Bays, Arden K. Hegtvedt & David P. Timmis. Principles of Oral and Maxillofacial surgery. Robert D. Marciani, Larry J. Peter, Steven M. Roser & A. Thomas Indresano. Lippincott – Raven publishers. Vol. III. 1997 :  1349 – 1414.
  6. Historical developments of orthognathic surgery. W. Steinhauser. Journal of cranio-Maxillofacial surgery. 1996: 24 : 195 – 204.
  7. Rigid fixation for Le fort I maxillary surgery. John Paul Stella & Bruce N Epker. Controversies in Oral & Maxillofacial surgery. Philip Worthington & John R. Evans. W. B. Saunders company. 1994. 159 – 164.
  8. Unusual complications of the Le Fort I Osteotomy. Richard Bendor Samuel. Plastic and Reconstructive surgery. 1995 : 96 : 1289 –1297.
  9. Maxillary and midface deformity. William H. Bell, David Darab & Zhihao You. Modern practice of orthognathic and reconstructive surgery. William H. Bell. B. Saunders company. 1992. Vol. III. 2211 –2333.
  10. Oblique modified LE fort III osteotomy. J. M. Garcia Y Sanchez, J. T. Davila, A. B. Gomez Pedrozo, H. S. Mendoza & D. L. Vargas. Modern practice of orthognathic and reconstructive surgery. William H. Bell. B. Saunders company. 1992. Vol. III. 1770 –1789.
  11. Quadrangular Le fort I and Le fort II osteotomies. E. Keller. Modern practice of orthognathic and reconstructive surgery. William H. Bell. W. B. Saunders company. 1992. Vol. III. 1790 – 1837.
  12. Role of the total maxillary alveolar osteotomy in orthognathic surgery. Sterling R. Schow. Current advances in Maxillofacial surgery: Orthognathic surgery. David W. Shelton & William B. Irby.. The C. V. Mosby company. Vol V .1986.48 – 99.
  13. Surgical approach to the facial bones. F. Moos. Surgery of the Mouth and the Jaws. J. R. Moore. Blackwell Scientific Publications. 1985. 75 – 93.
  14. Osteotomy technique – Midface. K. F. Moos. Surgery of the Mouth and the Jaws. R. Moore. Blackwell Scientific Publications. 1985. 130 – 173.
  15. Maxillary excess. William H. Bell. & William R. Proffit. Surgical correction of dentofacial deformities. William H. Bell, William R. Proffit & Raymond P. White. B. Saunders company. Vol. I. 1980. 234- 441.
  16. Maxillary and midface deformity. William H. Bell, William R. Proffit, Joe D. Jacobs, Derek Henderson, Timothy A. Turvey & David J. Hall. Surgical correction of dentofacial deformities. William H. Bell, William R. Proffit & Raymond P. White. B. Saunders company. Vol. I. 1980. 442 – 683.

^^^^^^^^^^^^^^^