Posted in Trauma

Mandibular Fractures

 CLINICAL FEATURES AND MANAGEMENT

INTRODUCTION:

Fractures of the mandible are common in patients who sustain facial trauma.

Study conducted by Hang et al, showed the ratio of 6:2:1 of mandibular, zygomatic, maxillary fractures incidence respectively. Approximately 2/3rds of all facial fractures are the mandibular fractures.

The management of the mandibular fractures includes conservative and open reduction methods.

The management of mandibular fractures was proposed by various practitioners and authors are as follows:

Erich and Austin (1844) – Preantibiotic era, closed reduction.

Buck, (1847) – Transosseous silver wiring.

Gordon (1942) – Wire suturing, stainless intraosseous wiring + MMF.

Spiessl (1970) – AO / ASIF – compression plate.

Michelet (1973) – Non compression, monocortical screws with miniplate system.

Champy (1978) – Ideal osteosynthesis lines.

CLASSIFICATION

  1. Anatomical Location

Row and Killey’s classification

  1. Fractures not involving the basal bone – are termed as dentoalveolar fractures.
  2. Fractures involving the basal bone of the mandible.

Subdivided into following:

  1. Single unilateral.
  2. Double unilateral.

Dingman and Natvig’s classification by anatomic region:

  1. symphysis fracture (midline fracture).
  2. Canine region fracture.
  3. Body of the mandible between canine and angle.
  4. Ramus region – bounded by the superior aspect of the angle to two lines forming an apex at the sigmoid notch.
  5. Coronoid region.
  6. Condylar fractures.
  7. Dentoalveolar region.
  8. Relation of the Fracture to the Site of injury

 

  1. Direct fractures.
  2. Indirect (countercoup)fractures.
  3. Completeness

Complete and incomplete fractures.

  1. Depending on the mechanism
  2. Avulsion fracture.
  3. Bending fracture.
  • Burst fracture.
  1. Countercoup fracture.
  2. Torsional fracture.
  3. Number of Fragments:
  • Single, multiple, comminuted, etc.
  1. Involvement of the integument
  • Closed or open fracture.
  • Grades of severity I-V
  1. Shape or area of the Fracture
  • Transverse, oblique, butterfly, oblique surfaced.
  1. According to the Direction of Fracture and Favourability for treatment
  2. Horizontally favourable fracture.
  3. Horizontally unfavourable fracture.
  4. Vertically favourable fracture.
  5. Vertically unfavourable fracture.

This classification is aimed toward the angle fractures. Here, the direction of fracture line is important for resisting the muscle pull. When the muscle pull resists the displacement of the fragments then the fracture line is considered as favourable. If the muscle pull distracts the fragments away from each other, resulting in displacement, then the fracture line is considered as unfavourable.

  1. When the fracture line passes from the alveolar margin, downward and forward, then upward displacement of the posterior fragment is prevented by physical obstruction caused by the body of the mandible. Hence, such a fracture line is termed horizontally favourable.
  2. If, on the other hand, the line of the fracture passes downward and backward, then the upward movement of the posterior fragment is unopposed. This type of fracture is termed horizontally unfavourable.
  3. The fracture line which passes from the outer or buccal plate obliquely backward and lingually, will tend to resist the muscle pull and is thus termed a vertically favourable type of fracture.
  4. When the fracture line pass from the inner or lingual plate obliquely backward and buccally, inward movement of the posterior fragment will take place as a result of the medial pterygoid muscle pull. This type of fracture is termed vertically unfavourable.

This classification is of clinical importance for the treatment planning and fixation, the amount of displacement can be judged and the type of fixation device can be chosen.

  1. According to Presence or Absence of Teeth in Relation to the Fracture line

It is very essential to note the presence or absence of teeth in relation to the fracture line, also the periodontal status as well as teeth size also matters for planning fixation method.

Kazanjian and converse classification

Class I when the teeth are present on both sides of the fracture line.

An adequate number of teeth of suitable shape and stability. Wiring – direct, continuous or multiple loop or interdental eyelet type, use of prefabricated arch bars.


Class II When the teeth are present only on one side of the fracture line.

  1. Short edentulous posterior fragment
  2. If favourable, immobilization of main fragment by interdental wiring or arch bars. Minor displacement can be accepted.
  3. If unfavourable – open reduction with direct fixation is a must.
  4. Long edentulous posterior fragment:
  5. Without displacement – conservative treatment.
  6. With vertical and medial displacement requires open surgical reduction and fixation.

Class III When both the fragments on each side of the fracture line are edentulous.

  1. Simple or compound fracture without much displacement in the body region. Simple Gunning type splints.
  2. Simple fractures which are unfavourable. Open reduction and fixation.
  • Compound fractures. Surgical intervention.
    • AO Classification (Relevant to Internal Fixation)
  1. F: Number of fracture or fragments.
  2. L: Location (site) of the fracture.
  3. O: Status of occlusion.
  4. S: Soft tissue involvement.
  5. A: Associated fractures of the facial skeleton

Such a classification is helpful in terms of:

  • Patient selection and treatment planning.
  • Evaluation of therapeutic results.
  • Comparison of different treatment methods.
  • Information and communication.

These criteria can be objectified clinically and radiographically:

  1. F: Number of fracture.

F0: Incomplete fracture.

F1: Single fracture.

F2: Multiple fracture.

F3: Comminuted fracture.

F4: Fracture with a bone defect.

  1. Categories of localization (site) L1-L8

L1: Precanine.

L2: Canine.

L3: Postcanine.

L4: Angle

L5: Supra-angular

L6: Condyle

L7: Coronoid.

L8: Alveolar process

 

  1. Category of occlusion – O0-O2

O0: No malocclusion.

O1: Malocclusion.

O2: Non existent occlusion – Edentulous mandible.

  1. Categories of soft tissue involvement – S0-S4

The risk of infection and healing depends on the condition of the soft tissues surrounding the fracture.

S0: Closed.

S1: Open intraorally.

S2: Open extraorally.

S3: Open intra and extraorally.

S4: Soft tissue defect.

  1. Categories of associated fractures A0-A6

A1: Fracture and / or loss of tooth.

A2: Nasal bone.

A3: Zygoma.

A4: LeFort I

A5: LeFort II

A6: LeFort III

Grades of severity – I-V

Grade I and II are closed fracture.

Grade III and IV – open fractures.

Grade V open fracture with a bony defect (gunshot).

Condylar Fractures:

According to the fracture level:

  1. Condylar head or intracapsular.
  2. Condylar neck.

Relationship of condylar fragment to the mandible:

  1. Displaced with medial overlap of the condylar fragment.
  2. Displaced with lateral overlap.
  3. Anterior and posterior overlap.
  4. Without contact between the fragments.

Relationship of condylar head to fossa:

  1. No displacement.

 

 

CLINICAL EXAMINATION

Examination of a patient with mandibular fracture is done in 3 stages:

  • Immediate assessment and treatment of life threatening conditions if any.
  • General clinical examination.
  • Local examination of the mandibular fracture.

The signs and symptoms of mandibular fractures are as follows:

  1. Change in occlusion:

This is highly suggestive of a mandibular fracture, and the bite will feel different. This may occur due to fractured teeth, alveolus mandible, or trauma to TMJ and muscles of mastication.

  • Anterior open bite may occur due to bilateral angle or condylar fractures or from maxillary fractures with inferior displacement of the posterior maxilla.
  • Posterior open bite can occur with fractures of the anterior alveolar process or parasymphyseal fractures.
  • Unilateral openbite – ipsilateral angle and parasymphyseal fractures.
  • Posterior crossbite-midline symphyseal or condylar fractures with splaying of the posterior mandibular segments.
  • Retrognathic occlusion – condylar/angle fractures and forwardly displaced maxillary fractures.
  • Prognathic occlusion – effusion of TMJ, protective forward positioning of the mandible, retropositioning of the maxilla.
  1. Anesthesia, paresthesia or dyesthesia of the lower lip:

Most pathognomonic sign of a fracture distal to the mandibular foramen, causing damage to the inferior alveolar nerve.

Conversely, most non displaced fractures of the body angle and symphysis are not characterized by anesthesia, so this is not a sole diagnostic feature in diagnosis.

  1. Abnormal mandibular movements:

Usually limited opening and trismus due to guarding of muscles of mastication are seen, but certain predictable abnormal movement are seen in certain cases, e.g. deviation to the same side on opening seen in condylar fractures, therefore lateral pterygoid of normal side is not counteracted by that of the fractured side.

  • Inability to open the jaw may be due to impingement of the coronoid on the zygomatic arch, either from fractures of the ramus and coronoid process, or from a depressed zygomatic arch fracture.
  • Inability to close the jaw due to fracture of alveolar process, angle, ramus, or symphysis causing premature dental contact.
  • Lateral mandibular movements may be inhibited by bilateral condylar fractures, and fracture ramus with bone displacement.
  1. Change in facial contour and mandibular arch form:
  • May be masked by swelling.
  • Flattened appearance of lateral aspect of face may be due to fracture body, angle or ramus.
  • Deficient mandibular angle – unfavourable angle fractures where proximal fragment rotates superiorly.
  • Retruded chin – bilateral parasymphyseal fractures.
  • Elongated facial appearance – bilateral subcondylar, angle or body fractures, which allows the anterior mandible to be displaced downwards.
  • Facial asymmetry.
  • Change in arch form.


  1. Lacerations, haematoma and echymosis:

Trauma significant enough to cause loss of skin or mucosal continuity or subcutaneous / submucosal bleeding certainly can cause trauma to the underlying mandible. The direction and type of fracture may be visualized directly through the laceration. The common practice of closing facial lacerations before treating underlying fractures should be discouraged.

Echymosis in the floor of the mouth indicates mandibular body or symphyseal fracture.

  1. Loose teeth and crepitation on palpation.

Multiple fractured teeth that are firm indicate that the jaws were clenched during the traumatic insult, thus lessening the effect on the supporting bone.

Crepitation will be felt in a fracture on palpation.

  1. Dolor, tumor, rubor, calor.

The signs of inflammation are excellent primary signs of trauma and can greatly increase the index of suspicion for mandibular fractures.

The 3 principles in the treatment of mandibular fracture are include Reduction, Fixation and Immobilization.

 

Champy’s Ideal Osteosynthesis Lines

Mandible has parabola shaped body. It consists of the outer and inner cortical plates with central spongiosa. The external cortex is strong and thicker in chin region. It is reinforced laterally by the external oblique line strong projection. In the chin region, there is a stronger cortex inferiorly at the lower border. By the virtue of its compact bone, it provides good anchorage for osteosynthesis screws. In the tooth bearing areas, alveolar proess is of variable thickness. Screw fixation in this area is not possible, due to the anatomy of the roots of the teeth and structure of the bone. The mandibular canal runs from lingula to the mental foramen on a concave course directed upward and forward. Traced from behind forward, the inferior alveolar nerve runs closer to the outer cortex and to the lower border (8 to 10mm from lower border). Distance between the nerve and the outer cortex ranges between 4 to 6mm. The mental foramen lies higher than the canine apices (no osteosynthesis).

In every mandibular fracture, the forces of mastication produce tension forces at the upper border and compression forces at the lower border. Therefore, distraction of the fractured fragments will be seen at the alveolar crest region. In the canine region, there are overlapping tensile and compressive loads in both the directions. Besides this torsional forces are also significant.

The experimental exercise on the model and on the fractured mandibles have confirmed the values calculated on the normal mandible is 60DaN (maximum) in molar region and 100DaN in the incisor region, allowing for the additional torsional forces. Taking into account these anatomical factors, the determination of these forces allows the establishment of ‘an ideal osteosynthesis lines’ for the mandibular body. It corresponds to the course of a line of tension at the base of the alveolar process. In this region a plate can be fixed with monocortical self tapping screws. Behind the mental foramen, a plate can be applied immediately below the dental roots and above the inferior alveolar nerve. At the angle of the jaw, the plate is most favourably placed on the broad surface of the external oblique line as high as possible. In the anterior region between the mental foramina, in addition to the subapical plate, another plate near the lower border of the mandible is necessary in order to neutralize torsional forces. Second plate is applied parallel to the first plate with a gap of 4.5mm between them.

Reduction:

Reduction of a fracture means the restoration of a functional alignment of the bone fragments.


Closed reduction:

Implies fracture reduction without opening skin or mucosa. It is a blind procedure relying on the fragments locking together. This is most likely if the periosteum is intact. E.g. I.M.F, M.M.F.

The reduction normally occurs without direct visualization of the fragments in final positions. The commonest method of closed reduction relies on correct positioning of teeth to control the reduction. The teeth are used to assist the reduction, check alignment of the fragments and assist in immobilization.

Advantages and disadvantages of closed reduction:

Advantages:

  • Only stainless steel wires needed (usually arch bars also).
  • Easy availability, convenient.
  • Short procedure, stable.
  • Gives occlusion some “leeway” to adjust itself.
  • Generally easy, no great operator skill needed.
  • Conservative, no need for surgical tissue damage.
  • No foreign object or material left in the body.
  • No operating room needed in most cases, outpatient treatment.
  • Callus formation (secondary bone healing) allows bridging of small bony gaps.

Disadvantages:

  • Cannot obtain absolute stability (contributing to nonunion and infection).
  • Non compliance from patient due to long period in IMF.
  • Difficult (liquid) nutrition.
  • Complete oral hygiene impossible.
  • Possible temperomandibular joint sequelae.
  • Muscular atrophy and stiffness.
  • Denervation of muscles alteration in fibre types.
  • Changes in temperomandibular joint cartilage.
  • Weight loss.
  • Irreversible loss of bite force.
  • Decrease range of motion of mandible.
  • Risks of wounds to operators manipulating wires.

Open reduction:

Open reduction involves exposure of the fracture through either the skin or mucosa and fracture segments are visualized and reduced.

Indications for open reduction:

  1. Displacement unfavourable fractures through the angle of mandible.
  • When proximal fragment is displaced superiorly, medially and cannot be maintained without intraosseous wires, screws or plating.
  1. Displaced unfavourable fractures of the body or the parasymphyseal region of the mandible.
  • When treated with closed reduction parasymphyseal fracture tend to open at the inferior border with the superior aspect of the mandibular segments rotating medially at the point of fixation.
  1. Multiple fracture of the facial bones.
  • In multiple fracture of the facial bones, open fixation of the mandibular segments provide a stable base for restoration.
  1. Midface fractures and displaced bilateral condylar fractures.
  • With midface frace and displaced bilateral condylar fracture, one of the condylar fractures should be opened to establish the vertical dimension of the face.
  1. Fractures of an edentulous mandible with severe displacement of the fracture segments.
  • Open reduction should be considered to reestablish continuity of the mandible.

Advantages and disadvantages of open reduction with rigid internal fixation.

Advantages:

  • Early return to normal jaw function.
  • Normal nutrition.
  • Normal oral hygiene after a few days.
  • Avoidance of airway problem.
  • Can get absolute stability, promotes primary bone healing.
  • Bone fragments re-approximated exactly by visualization.
  • Avoids IMF for patient with occupational benefits in avoiding mandible fixation e.g. Lawyers, teacher, sale people, seizure disorders.
  • Helpful in special nutrition requirements (diabetics, alcoholics, psychiatric disorders, pregnancy).
  • Easy oral access (for example in intensive care unit patients).
  • Decreased patient discomfort, greater patient satisfaction.
  • Less myoatrophy.
  • Decreased hospital time.
  • Substantial savings in overall cost of treatment.
  • Lower risk of major complications.
  • Lower infection rates, improved overall results.
  • Lower rate of malunion/nonunion?


Disadvantages:

  • Most obvious; need for an open procedure.
  • Significant operating room time.
  • Prolonged anaesthesia.
  • Expensive hardware.
  • Some risk to neuromuscular structure and teeth.
  • Need for secondary procedure to remove hardware.
  • “Unforgiving procedure”, the rigidity of the plate means no manipulation is permissible.
  • Need much operator skill, meticulous technique needed.
  • Higher frequency malocclusion.
  • Higher frequency facial nerve palsy.
  • Scarring (extraoral and intraoral).
  • No bridging of small bone defect (absence of callus)

Closed reduction and indirect skeletal fixation:

  1. Direct interdental wiring.
  2. Indirect interdental wiring (eyelet).
  3. Continuous or multiple loop wiring.
  4. Arch bars.
  5. Cap splints.
  6. Pin fixation.
  • Direct interdental wiring:

This method was introduced by Gilmer, this technique provides simple and rapid method of immobilization of jaws. But with this technique the wire tend to loosens and a broken direct wire cannot be replaced without first removing and then replacing all of the others.

A 15cm length of prestretched 0.35mm diameter soft stainless steel wire is passed around a tooth emerging through the interdental space with the wire around the neck of the tooth the two ends of the wire are tightened by twisting together to produce a 3cm tail.

For intermaxillary fixation the maxillary wire ends are twisted together with mandibular once. The cut ends should be bent in to the interdental space to avoid soft tissue trauma.

  • Indirect interdental wiring (eyelet or ivy loop):

Eyelet wiring is simple, quick, easyway and effective method of reduction and easy way of obtaining maxillomandibular fixation.

If immobilization of the jaws is required for a short period only, relatively few eyelets are necessary e.g. one or two in each quadrant.

 

 

Technique:

The loop is constructed of a 24 gauge wire and the wire is passed interproximal to two stable teeth. The ends of the wire are first brought around to the mesial and distal sides of the teeth. The distal end wire is then delivered under the loop and tightened to the mesial wire in apical direction. Then the cut ends of wire are adapted in the interproximal space.

Maxillomandibular fixation between eyelets can be achieved by passing a smaller gauge wire can be passed through the loops and tightened. The posterior tie wire should be tightened first to avoid excessive traction on the lower anterior teeth. The twist is to be made at the gingival margin and traction is applied to the wire in that direction to lessen the possibility of it breaking. The cut ends are bind tightly and should be intersected into the interdental space to avoid trauma.

Removal of eyelet wire: The normal period required for firm clinical union to take place in healthy adult is 6weeks with young patients and with minimally displaced fractures 3 to 4 weeks will allow adequate union.

 

 

  • Continuous or multiple loop wiring:

Stout (1943) described a technique which permits blocks of teeth in either jaw to be wired in such a manner that elastic traction can be used to reduce the fracture.

Technique:

A 30cm length of soft 0.5mm diameter stainless steel wire is used. One end of the wire is laid along the buccal surface of the teeth, while the other is passed around the most posterior teeth below its contact point to emerge through its anterior interdental space. The wire is passed around the buccal wire and back through the same interdental space. A pliable rod approximately 3mm diameter and 5cm in length is passed through the wire loop and laid along the buccal surface of the segment parallel to the buccal wire. The end of the wire on lingual or palatal aspect is then passed in sequence through the interdental space of remaining teeth around the rod and the buccal wire in a similar manner until the quadrant is closed. Then both the ends of the wire lie on buccal aspect, they are clipped pulled and twisted. Then the rod is withdrawn by a forward rotatory pull. First the posterior and each succeeding loop is twisted by an artery clip so that the loop lies horizontally.

 

ARCH BARS

Are the most versatile form of mandibular fixation.

There are two varieties of arch bars, those that are commercially produced and those which are individually made for a given patient.

Commercially:

  • Jelanko
  • German silver bars.

Indications for use:

  1. When insufficient teeth remain to allow efficient eyelet wiring.
  2. When teeth present are so disturbed that efficient intermaxillary fixation is otherwise impossible.
  3. In case of simple dentolaveolar fractures or where multiple tooth bearing fragments in either jaw require reduction into a arch form before intermaxillary fixation.
  4. As an integral part of internal skeletal suppression in the treatment of fractures involving the middle third of facial skeleton.
  5. To reduce the preoperative time which would otherwise be required for cap splint preparation.

Technique:

As the mandibular fragment are displaced owning to the fracture the bar is cut and adapted to maxillary arch. In practice it has been found that such a bar is quite satisfactory when applied to the lower arch as extreme accuracy is not required. It is advisable to wire one end to the posterior teeth of a principal fragment, then to secure the anterior section of arch bar in the incisor region and finally attach the other end. This permits adjustment of the length and contour before the intervening wires complete the attachment of the bar.

To be retentive the wires holding the bar must lie below the contact points.

They may be inserted as follows:

  1. Passed around the lingual or palatal aspect of tooth and tightened over the bar.
  2. Passed circumferentially around the entire tooth before being tightened over the bar.
  3. Both ends of wire loop are passed around the tooth one end passes over the bar and is inserted through the loop while the other end passes under the bar and remains fine of loop. The two ends are pulled to tighten the loop and the wires are twisted over the bar.

Once the fragments have been tightly secured to the arch bar, it is difficult to correct any errors in a vertical displacement of occlusion. It is advisable therefore not to tighten any ligature finally until all have been inserted any vertical displacement has been corrected by articulating the jaws.

PIN FIXATION

This technique was introduced during the second World War for use with compound, communited and frequently infected jaw fractures as a means of controlling the fragments remote from the affected area.

Indications:

  1. Pathologic fracture or gunshot injuries associated with gross bone loss.
  2. Osteomyelitis of an edentulous fracture site.
  3. Fractures associated with extreme atrophy of the edentulous jaw.
  4. Fractures of mandible associated with fractures of the middle third of facial skeleton.

Advantages of pins:

  1. Control of the edentulous fragments without involving the fracture lines.
  2. Can be applied under local analgesics if indicated.
  3. Reduction or avoidance of the need for surgery at the fracture site, thereby retaining the periosteal blood supply of the edentulous mandible.
  4. Elimination of laboratory facilities, with minimum operative time required.
  5. Simultaneous treatment of middle third and mandibular fractures by relatively simple combined techniques.
  6. Immobilization of the mandible may be less prolonged or even avoided.

Disadvantages of pins:

  1. Conspicuous in daily life and uncomfortable while sleeping because of the projection of the pins which may easily be knocked.
  2. Difficult with washing and shaving.
  3. Soft tissue scars are caused by the pinholes and there is a constant, although slight, risk of infection.
  4. Readily accessible to an interfering, uncooperative or cerebrally irritated patient.

Technique:

Consist of inserting into each major bone fragment a pair of 3mm titanium or stainless steel about 7cm long which diverge from each other by means of universal joint. Self tapping pins such as moule or toller type are used, these being screwed into prepared holes in the bone of slightly diameter. After reduction of the fracture the pairs of pins are linked by attaching a connecting rod or rod to the centre of the cross bar by means of universal joints.

  • Pin fixation of this nature is not particularly rigid and supplementary intermaxillary fixation is usually required.

CAP SPLINTS

Silver cap splints were for many years the method of choice for the immobilization of all jaw fractures especially in U.K. during the second world war this technique was of great importance.

  • This technique is time consuming both clinically and in the laboratory and the results achieved are accomplished better and faster by other method.

 

 

Indications:

  1. Patients with extensive and advanced periodontal disease when a temporary retention of dentition is required during the period of fracture healing. A cap splint will splint all the loose teeth together and allow application of intermaxillary fixation.
  2. To provide prolonged fixation on the mandibular teeth in a patient with fractures of the tooth bearing segment and bilateral displaced fractures of the condylar neck. The cap splint will immobilize the body fracture and allow mobilization and if necessary, intermittent elastic traction for condylar fracture.
  3. Where a portion of the body of the mandible is missing together with substantial soft tissue loss.
  • Silver cap splints are usually cemented with black copper cement because this material will form a firm bond in the presence of a limited amount of moisture. It is also a useful abundant for retained teeth which have exposed and sensitive dentures.

Acrylic cap splints: are easily and more cheaply fabricated. They are particularly useful for the treatment of dislocated teeth and alveolar segmental fractures.

SURGICAL APPROACHES

Factors used to establish the location of incision include:

Fracture location                     Approaches :

Skin lines                                          Extraoral

Nerve position                                  Intraoral

Extraoral approaches

  1. Submandibular approach:

First described by Risdon in 1934, the skin incision is 4-5cm in length, 2cm below the angle of the mandible. Optimally the incision should be placed within a skin crease, so as to hide the scar.

  • Subcutaneous fat and superficial fascia are dissected to reach the platysma muscle.
  • The platysma is sharply dissected to reach the superficial layer of the deep cervical fascia. Marginal mandibular branch lies just deep to it.

The nerve passes above the inferior border of the mandible till the region where the facial artery crosses the inferior border, and then takes a downward course, upto 1cm below the inferior border. These branches below the inferior border distal to facial artery supply the platysma.

Dissection through the deep cervical fascia is done with the careful use of a nerve stimulator. The submandibular gland and its fascia then becomes evident, and the lower pole of the parotid may be seen. Dissection is then carried to the masseter taking care to retract the nerve fibers superiorly.

Once the muscle is encountered, it is sharply divided at the inferior border to expose the bone. The muscle, periosteum and soft tissues are retracted superiorly to expose the body ramus and fracture site.

Exposure can be increased and closure enhanced by dissecting the medial pterygoid and stylomandibular ligament from the inferior and posterior border. Further exposure can be obtained by distracting the angle and inferior border with a wire or bone forceps.

The capsules of parotid and submandibular glands should be avoided, or else disruption of gland parenchyma may lead to sialoceles or salivary fistulas.

  1. Retromandibular approach

Described by Hinds and Girotti in 1967. Basically a variation of the submandibular approach, except that the incision was 3cm above the submandibular incision.

The incision curves behind the angle of the mandible and the parotid, and massetric and deep cervical fascia are encountered. The dissection is then carried anterior to deep cervical fascia, and nerve stimulation is used. The incision to bone through the masseter is between the marginal mandibular and buccal branches of the facial nerve. The muscle and periosteum are incised over the angle. The soft tissues and nerve fibers are then retracted superiorly.

This incision gives superior access to the ramus and subcondylar region.

  1. Preexisting lacerations:

These lacerations may be made use of, if present, to gain access to the fracture site, if it is in direct relation to the fracture site.

Intraoral:

  1. Symphysis and parasymphysis:

Initially the region is infiltrated with LA and vasoconstrictor. The lip is then retracted, and a curvilinear incision is made perpendicular to mucosal surface. The incision is carried out into the lip so as to leave at least 1cm of attached gingiva.

The mentalis muscles now visible should be incised perpendicular to the bone, leaving a flap of muscle attached to the bone, for closure. The dissection is then carried sub periosteally to identify the mental neurovascular bundle.

The fracture site is then identified and reduced, and the surgical site is closed in layers. An adhesive bandage is then applied to the chin to support the mentalis muscle and thus prevent drooping.

  1. Body, angle and ramus

These regions can be approached through an extended wards incision.

Treatment by open reduction and dental skeletal fixation:

  1. Transosseous wiring (osteosynthesis).
  2. Intramedullary pinning.
  3. Titanium mesh.
  4. Circumferential straps.
  5. Bone clamps.
  6. Bone screws.


Transosseous wiring:

Is the direct skeletal fixation of two or more bone fragments with the aid of wire ligatures pulled through previously drilled holes.

  • Direct wiring keep the fragments in exact anatomic alignment after reduction, but additional fixation of the fracture mandible with splints and intermaxillary fixation is required to maintain stability.

Indications:

  1. For fractures of the ramus.
  2. For replacement of small fragments in grossly comminuted fractures.
  3. For functional stabilization of the fragments in plate and screw osteosynthesis.
  4. Edentulous mandibular fractures.

Contraindications:

  1. Fractures which are compound into the mouth should be treated with degree of reserve, as there is risk of infection from oral cavity tracking down the fracture line.


Technique:

The holes are drilled in the bone ends on either side of the fracture line 6mm distance after which a length of 0.45mm soft stainless steel wire is passed through the holes and across the fracture. After accurate reduction of the fracture the free ends of the wire are twisted tightly, cut off short and twisted ends tucked into the nearest drill hole.

Depending on type of fracture, various shapes of wire ligature are recommended:

  • Simple ligature is the most frequent form of ligature used but is only used to secure small bone fragments.
  • Most stable form of ligature is simple ligature combined with figure of eight and is recommended for stabilizing transverse as well as oblique fractures of the mandible at lower border.
  • Double ligature – also found to be static with respect to tension and bonding forces, one is placed below and the second above the mandibular nerve.
  • There is a risk of tooth root damage, so it is indicated in edentulous mandible.
  • The wiring osteosynthesis can be performed via either an intraoral or extraoral the extraoral provides a good overview of the fracture sites of the distal parts mandibular body including the angle.

Compression osteosynthesis:

The goal of a compression osteosynthesis is a condition called absolute stability in which no movements occurs at the area of interfragmentary contact or between the bone and the device.

Compression of the fractured bone segments enhances the likelihood of successful primary bone healing in two ways:

  • First is preload, the force generated across the fracture by fixation system.
  • Second component is the friction produced by compression of fracture bone segments.
  • The effect produced by interfragmentary compression help stabilize the fracture, minimizing complication such as osteomyelitis and non-union.
  • The maximum compressive force generated from compression plate is 300 kilopascals /cm2.
  • Ideally the favourable site for osteosynthesis is the region of maximal tension caused by muscular pull, which is the superior border of mandible. Because of the roots of the teeth and inferior alveolar canal, insertion of a plate in this locations is associated with unacceptable morbidity, so the plate only be inserted at the lower inferior border is capable of providing compression to the bone fragments, but fails to control the tensile forces at the alveolar process.

Dynamic compression plate:

The dynamic compression plate was originally designed for orthopedic surgery by the A.S.I.F. Lhur in 1972 adapted the principle of dynamic compression to the maxillofacial region for treatment of mandibular fractures. Spiessel et al was the first to apply the A.S.I.F. principles to the management of mandibular fractures.

  • Compression plates are available in thickness of 2.0mm, 2.7mm and 3.0mm and width of 6.5mm, 8.9mm. The indigenous design of compression plate is based on the screw head that when tightened slides down on inclined plane within the plate.

In dynamic compression plate one compression hole should be located in each fragment of fracture these holes are usually placed most proximal to the line of fracture. The screw movement produced from the inclined planes of there holes oppose each other, the fracture end will move toward one another relative to the plate.

The each compression hole will produce 0.8mm of bone movement and if compression is used on both sides a total of 1.6mm of bone movement may be achieved.

Technique: Before the plate is adapted to the bone, pretension across the fracture is achieved with the use of bone forceps. The use of bone forceps facilitate anatomic reduction.

Before the forces can be applied a hole must be drilled in the inferior aspect of the mandibular on each side of the fracture. These holes are ideally placed 1cm from fracture margin and screw is placed in each hole and the sleeves of the forceps are secured to these screws.

After reduction the plates are adapted and after proper adaptation of the plate the holes are made with appropriate size drill. The screws used are not self tapping and designed to engage both buccal and lingual cortices of mandible.

  • The drill is used through a drill guide toward the fracture. The guide has two numbers engraved on its surface 0.8mm and 0mm when the side marked 0.8mm towards the fracture line, any screw placed in this site will cause compression across the fracture. If portion labeled 0mm is located towards the fracture the screw will be placed in a passive position.
  • A depth gauge is used to establish the proper length screw. A screw of suitable length should be choosen so that when fully tightened it will project approximately 2mm through the lingual cortex.
  • When compression across the fracture is desired the compression holes should be drilled first. The first screw is tightened to hold the plate in position, but is not completely sealed, the second compression screw is placed on the either side of the fracture and is tightened initiating compression after 2nd screw is sealed the first screw is tightened fully maximizing compression. Then the remaining screws may be placed in passive position.

Eccentric Dynamic Compression Plate:

In 1973 Schomaker and Niederdellman developed a plate incorporating the principle of eccentric dynamic compression.

  • The design of the plate is similar to the D.C.P. In addition to the standard compression holes the plate also contains two oblique outer compression holes. The eccentric holes are aligned at an angle oblique to the long axis of the plate. The activation of these holes produce a rotational movements of the fracture segment. The rotational movement of the fracture segment establishes compression at the sup border of mandible.
  • When E.D.C.P. is applied an initial compressive force of 200N was observed at inferior border of mandible. As oblique screws are activated the compression at the base of mandible decrease to 150N, but compression of 150N was observed at the superior border of mandible. The superior compression also depends on the degree of oblique hole from the long axis of plate.

Technique:

A different bone reduction forceps is used and the sequence in which screws are inserted are also different. The reduction forceps incorporate pressure rollers that are located lateral to the holding screws once the holding screws have been engaged, anatomic reduction and precompression achieved, then the outer rollers are tightened which produces an occlusally directed forces on outer aspect of fracture, creating superior border compression.

  • Screws are placed in the holes closest to the fracture margin to achieve compression of fracture segment. After compression has been achieved at the inferior border screws are placed in the outer eccentric holes and tightened achieving compression at superior border.

Monocortical miniplate osteosynthesis:

The principle of miniplate technique is to identify the line of lesion within the mandible at the site of fracture. Then plate is applied across the fracture along this line without compression.

Champy studied examined the load at different parts of the mandible: Post to the canine the mylohyoid muscle pull medially whereas anerior to the canine, the digastric and genial muscle tend to pull posteriorly.

Taking into account the anatomy of the mandible, the location of the dental apices and the thickness of cortical layer chamy determined an ideal line of osteosynthesis which corresponds to the course of a line of tension at the base of alveolar process.

Behind the mental foramen only one plate should be applied below the roots and above the inferior alveolar canal. In front of the mental foramen in order to neutralize lighter tension forces at the canine another plate near the lower border of mandible is necessary in addition to the subapical plate.

The miniplates requires screw to be fixed only in the outer cortex of mandible.


Plates and screws:

The plates have a thickness of 1mm and are 6mm wide. The distance between the holes are standardized and the plates with more holes are available and those with intermediate plating are also available self tapping screws are used from 5 to 15 mm in length and diameter is 2mm, screw head are designed to allow insertion at a 30° slant with respect to the plate surface screws 7 or 5mm in length are normally used in mandible.

Advantages:

  1. Because of reduced size of miniplate, smaller incision and less soft tissue dissection are required for their placement.
  2. Miniplates can be placed intraorally thereby avoiding an external scar.
  3. Because of smaller size and thinner profile of the miniplates they are less likely to be palpable possibly reducing the need for subsequent plate removal.
  4. Because the screws are monocortical the plates may be placed in area of mandible adjacent to tooth roots with minimal risk of dental injury.
  5. Because of smaller size and the malleability of the materials, miniplates can be easily contoured in 3 dimensions.

Disadvantages:

  1. They are not rigid as standard mandibular fracture plates and decreased rigidity may lead to torsional movements of the fracture segments leading to infection or nonunion.
  2. Because of instability the use of miniplates fixation for comminuted fracture is limited.
  3. Because of reduced stability of miniplate fixation reduced function is recommended (soft diet).

Clinical application:

When miniplate is used for fixation of a mandibular angle fracture, placement should at the superolateral aspect of mandible extending onto the broad surface of the external oblique ridge.

In the region between two mental foramina two plates are recommended one in the subapical region of symphysis and the second at the inferior border.

In the body of mandible one plate is recommended just below the apices of the teeth but above the inferior alveolar nerve canal.

Bioresorbable plates:

Disadvantages associated with metallic plates:

  1. Plate, induced osteoporosis.
  2. Because the plate may become infected.
  3. Loosening and corrosion of the screws may occur overtime, leading to inflammation and pain.
  4. Long term retention of metallic plates in the facial skeleton include palpability of the plate, interferences with the fit of prosthetic appliances.

The bioresorbable material would avoid the problems associated with the use of metallic materials while maintaining the qualities necessary for successful rigid fixation.

Bioresorbable materials used include:

  1. Polyglycolic acid.
  2. Polyactic acid.

These materials are tolerated well by the body but their strength inadequate to provide clinically acceptable rigid fixation.

  • The self reinforced polyglycolic acid and self reinforcing polylactic acid. The self reinforcing technique increases the strength of the material by incorporating polymeric fibres having the same chemical composition as the binding matrix.
  • The major advantage of bioresorbable rigid fixation device is that initially they provide adequate fixation for direct bone healing but as the bone gains strength the plate is reabsorbed by the body.
  • The metabolism of P.G.A. is primarily by hydrolysis. The individual glycolic acid molecule are metabolized via the citric acid cycle and ultimately eliminated by respiration as carbon dioxide.
  • The resorption rate of these material is 5.3µm/day.

Lag screw fixation:

Lag screw fixation for mandibular fracture was introduced in 1970 by Brons and Boering.

A screw acts as a lag screw when it gains purchase in the cortex of the most distant osseous fragment while fitting passively in the cortex of the fragment adjacent to the screw head.

The true lag screw has the thread in the distal end and a smooth shank at the proximal end (i.e. adjacent to the screw heal). An oversized hole is drilled through the proximal cortex. The diameter of this hole must be as large as the thread diameter of the screw. The remainder of the hole in the distal segment must be smaller than the thread diameter and this is referred to as traction hole when the screw is tightened the distal fragment is pulled against the proximal fragment by the screw head.

It is possible to achieve 2000 to 4000 N of compressive force when using lag screws, compared with the 600N achieved with compression plates.

Indications:

  • A typical indication for lag screw fixation are fractures in the chin region. Where the mandible is constituted by a strong cortical bone which serves as a excellent buttress.
  • In fracture of angle the lag screw may be installed on the tension side of the fracture which is biodynamically advantages.
  • Long sagittal fracture in the body regions.
  • Lag screws are used to reduce condylar fracture
  • Lag screws are useful for fixture of inlay and onlay bone group.

Technique:

First the gliding hole in drilled in the near cortex with a diameter equal to the treat of the screw. The traction hole is then prepared with the aid of a centering guide, assuring that the two holes are prepared coaxially. This is performed with smaller drill sleeve.

The depth gauze is inserted prior to tapping the traction hole. The traction hole is then tapped to the final size.

Intra medullary pinning

Intramedullary pinning was first advocated by major in 1938 and was used by McDowell for maxillofacial fracture.

Kirscher wire are widely used for intra medullary pinning. Approx 2mm indiameter. In emergency situation these wire can be used to provide temporary stabilization of a fractured mandible. The fracture is held in a reduced position and one or more wires drilled through the fragments so that past of wire passes through undamaged bone on each side of fracture.

This method is versatile and can be applied with appropriate ingenuity to fracture in any part of the mandible.

Stability offered by this technique however was not adequate for fixation of mandibular fracture.

Bone clamps:

Bone clamps form of rigid internal fixation and was introduced around 1970. the device was clamped to the lingual and buccal cortices of mandible around the inferior border. The Brenthurst splint is the best known example of this system. Instead of pin screw into the bore the fragments each side of the fracture are secured by clamps attached to the lower border of mandible pins which project from the clamp are the connected by a system of external rods and universal joints in a similar manner to that employed with external pin fixation used in à oblique fracture.

Disadvantages is slippage of clamps.

Complications:

Infection:

The overall post operative infection rate has been reported to be between 3% and 27%. The most common cause is mobility of fracture segments.

Technical errors such as inadvertent placement of screws in the line of fracture, poor plate adaptation and inadequate cooling of bone during screw hole preparation increase the risk of post operative infection.

Fractures in the proximal part of the mandibular body or in the angle region have a higher propensity for infection because of decreased cross sectional surface area of bone.

The other factors implicated in an increased rate of infection include extraction of molar teeth from the line of fraction. The extraction of teeth is indicated when there is periapical pathology, fractured, or severely displaced or those that prevent fracture reduction.

Nerve Injury:

Iatrogenic injury to the sensory branches of the trigeminal nerve is known to occur following open reduction. The nerve injury is often the result of over retraction and also occurs following the application of rigid fixation.

Injury to branches of facial nerve occasionally occurs during repair of mandibular fracture, in case of submandibular incision and approach to condyle the marginal mandibular nerve and temporal branches are damaged respectively.

Malunion:

Mal union is the healing of bone segments in a non physiologic position secondary to either nontreatment or inadequate treatment of a displaced fractures malunion may occur as a result of plate bending, plate fracture, loosening of screw or poor intraoperative reduction. In dentate portion of maxilla and mandible this leads to a malocclusion.


Delayed union:

The time taken for a mandibular fracture to unite is unduly protracted it is referred to as a case of delayed union. If union is delayed beyond the expected time for that particular fracture it must be assumed that the healing process has been disturbed. This is the result of local factor such as infection or general factors such as osteoporosis or nutritional deficiency.

Nonunion:

Means that the fracture is not only not united but will not unite on its own.

Causes:

  • Infection
  • Inadequate immobilization
  • Unsatisfactory opposition of bone ends with interposition of soft tissue.
  • Inadequate blood supply
  • General disease, e.g. Osteoporosis, nutritional deficiencies.

Restriction of craniofacial growth:

The rigid fixation affect the growth potential of the growing craniofacial skeleton.

  • Secondary surgery to remove plates and screws may have a greater detrimental effect on growth than does the retention of plates.

Scar:

Mandibular fractures have associated soft tissue injuries which leads to scar formation.

  • Open reduction with internal fixation often requires the use of extraoral incision.
  • When possible incision should be placed in existing skin creates a usually parallel to resting tension lines.
  • Prophylactic treatment for the patient a risk consist of local application of steroid tape and intratensional infection of 0.1ml of triamcinolone 40mg/ml at 2 to 3 weeks interval.

Injury to tooth roots:

There is always the possibility of trauma to the dental structures when placing screws in the dentate region of maxilla and mandible. This is more commonly seen with D.C.P.

Limitation of opening:

Prolonged immobilization of the mandible in intermaxillary fixation will result in weakening of the muscles of mastication. Excess haemorrhage within the muscles, considerable amount of organizing traumatoma and early scar tissue because limitation of opening and reduced mandibular excursion simple jaw exercise and mechanical exercise may be employed.

Fractures in Edentulous & Atrophic Mandible:

Following resorption of the alveolar process, the vertical depth of the subsequent denture-bearing area is reduced by approximately one-half and in some cases by considerably more. The resistance of the bone to trauma is further reduced.

The ageing process is also associated with significant changes in the vascular architecture. The endosteal blood supply from the inferior dental vessels begins to disappear and the bone becomes increasingly dependent on the periosteal network of vessels.

The denture-bearing area of the edentulous mandible is therefore not only more easily fractured, but also less well disposed to rapid and uneventful healing. If the fracture is simple with little or no displacement it will heal satisfactorily.

Reduction:

For the reasons already stated, precise anatomical reduction is not necessary in fractures of the denture-bearing area. This is fortunate because reduction is frequently difficult when there is over-riding of the bone ends. Reduction and subsequent fixation become more difficult as the mandible atrophies.

However, operative open reduction involves further disruption of the periosteal attachment which interferes significantly with postoperative repair of bone.

Methods of immobilization:

Direct osteosynthesis:

  1. Bone plates.
  2. Transosseous wiring.
  3. Circumferential wiring or straps.
  4. Transfixation with Kirschner wires.
  5. Fixation using cortico-cancellous bone graft.

Indirect skeletal fixation:

  1. Pain fixation.
  2. Bone clamps.

Intermaxillary fixation using Gunning-type splints.

  1. Used alone.
  2. Combined with other methods.

 

Special features associated with jaw features in children

The reparative process in children is rapid due to the increased metabolic rate and the high osteogenic potential of the periosteum. This results in early union, usually within 2-3 weeks, and delay in treatment for any reason is, therefore, a more serious problem than in the adult. Non-union or fibrous union is almost unknown and excellent remodeling occurs under the influence of masticatory stresses, even when there is imperfect apposition of the bone surfaces.

Due to its inherent elasticity, the developing bone predisposes to the characteristic ‘greenstick’ type of fracture. Fracture of the body of the mandible frequently show a considerable degree of displacement and the fracture lines tend to be long and oblique, extending downwards and forwards from the upper border of the mandible. This obliquity of the fracture line is quite different from that observed in the adult where the direction of the fracture line is usually downwards and backwards. Fractures of the neck of the condyle are usually of the ‘greenstick’ variety.

Before eruption, the developing permanent teeth occupy most of the maxilla and the body of the mandible. Eruption may be delayed and the involved teeth may subsequentlyh exhibit varying degrees of damage. Miniplates or transosseous wiring are used; the fixation must be placed near the lower border of the mandible.

Condylar fractures and injuries should always be viewed with concern in the growing child because of the possibility of impaired facial growth attributable to the injury.

FRACTURES OF THE MANDIBLE

An undisplaced crack fracture at the angle of the mandible or through the body may be treated without immobilization, but careful judgement is indicated in such cases.

Unless there is mechanical interference with mandibular movement, there is no indication for open reduction and derangement, both unilateral and bilateral condylar fractures or fracture dislocations respond well to muscle training exercises where the child is encouraged to close the mouth with the teeth in their correct occlusal relationship. If severe pain precludes such active treatment, a day or so of rest using a headcap and chinstrap may be necessary prior to the commencement of exercises. A unilateral fracture with occlusal derangement or a bilateral fracture that exhibits posterior displacement of the mandible and an anterior open-bite deformity will benefit from immobilization in centric relationship until stability of the occlusion is achieved; in practice this takes 2-3 weeks, after which active exercises are encouraged.

Care should be exercised in the placement of such plates in order to avoid damage to developing teeth.

When considering methods of immobilization of fractured jaws, Rowe (1969) found it convenient to subdivide patients into four groups based upon the state of the dentition at the time of injury.

Age in years Dental development
0-2 Eruption of the deciduous dentition is incomplete
2-4 Before the roots of the deciduous incisors show marked resorption, although many of the permanent teeth are partly formed.
5-8 Before resorption of the deciduous molars is advanced or the roots of the permanent incisors adequately developed
9-11 After adequate formation of the roots of the permanent incisors and first molar teeth, but before eruption of the premolars. Development of the paranasal air sinuses may predispose to fractures of the middle third of the facial skeleton

Infancy to 2 years old

Two categories of injury. The first is where the fracture is in the tooth-bearing part of the mandible and in practice this usually occurs in the region of the symphysis. The fracture should be treated essentially as an edentulous problem and the technique described by MacLennen (1956) is excellent. A prefabricated acrylic ‘Gunning-type’ lower splint with a thick lining of softened gutta-percha is pressed down over the lower teeth and alveolus following manual disimpaction and reduction of any displacement. The splint is retained in place by two circumferential wires placed one on either side of the fracture line.

Two to three weeks is generally sufficient to ensure union and any discrepancy in alignment is automatically adjusted by later bone growth.

The second type of fracture that has occurred proximal to the tooth-bearing area, i.e. through the angle, and it will be necessary to immobilize. In order to immobilize the mandible, the acrylic splint described above is modified to incorporate blocks in the molar region and these are hollowed out to accommodate soft gutta-percha on the alveolus, thus stabilizing the bite. Immobilization of the mandible may be effected by nasomandibular fixation as described by Thoma (1943) in which wires from the margins of the piriform aperture of the nose pass beneath the circumferential wires that secure the lower splint to the mandible.

When latoratory facilities and bone-plating systems are not available, open reduction and fixation of the fracture with a carefully placed transosseous wire may be carried out.

2-4 years old

Interdental eyelet wiring can be used. If there are gaps in the dentition an arch bar may be used. If there are gaps in the dentition an arch bar may be required or, if facilities are available, cap splints can be used. The latter are best avoided, since the cementing on of the splints and their subsequent removal and cleaning of the teeth necessitates considerable cooperation between operator and child.

If the fracture is within the tooth –bearing area of the mandible, a single one-piece lower cap splint, despite its other shortcomings, may often be the best method since immobilization of the lower jaw is avoided. If there is any doubt about the security of the cement fixation, this can be reinforced with the aid of two circumferential wires.

5-8 years old

It is between these ages that the greatest problems arise with regard to fixation of the mandible.

The anterior teeth are of littie or no use because the roots are either resorbed in the case of the deciduous teeth or incompletely formed in the permanent teeth.

These difficulties can generally be overcome by constructing partial maxillary and mandibular ‘Gunning-type’ splints with occlusal blocks, the exact construction being dependent on the precise location of the tooth loss.

The mandibular splint is secured by circumferential wires.

9-11 years old

In patients in this age group the development of the roots of the permanent incisor and first molar teeth has proceeded to the point where they can safely be employed for fixation, either by means of cap splints or arch bars.

Plating or transosseous wiring, particularly in the externally compound fracture, is also useful.

Clinical features

The clinical features of condylar fractures in children are similar to those in the adult.


Management

The primary aims of treatment of condylar fractures in children include the restoration of undisturbed joint function, a normal occlusion and avoidance of subsequent growth disturbance.

In children there is overwhelming evidence to support the conservative management of condylar fractures.

Rowe (1969) summarized the situation succinctly when he declared.

‘It is time to state unequivocally that there is no indication for the open reduction in the case of condylar fractures in children unless there is mechanical interference with mandibular movement.

In children fractures of the condylar neck are often the ‘greenstick’ variety.

When the fractured condyle is displaced, it usually undergoes remodeling under the influence of the physiological stresses and strains imparted by masticatory function.

The angular deformity of the neck of the condylar process is corrected and the reconstituted condyle frequently appears to be relocated in the glenoid fossa, even when there has been bilateral fracture dislocation.

Minor disturbance in occlusion will be rapidly corrected by further eruption of existing teeth and alveolar remodeling.

An unacceptable occlusal disharmony may occasionally be seen in unilateral condylar fractures and these can often be managed by means of a training flange or interarch elastic traction. If this management fails, a short period of immobilization is necessary.

Severe disturbances of the occlusion are most commonly encountered after bilateral fracture dislocation, with open bite and possible retro-positioning of the mandible.

Treatment in these instances should, as in the case of the adult, be by a conservative immobilization regime.

 

TREATMENT OF CONDYLAR FRACTURES

3 main schools of treatment have been evolved.

CONSERVATIVE:

Relies on used of rest and immobilization by IMF for a period of 7-10 days – to allow muscle spasm and telescoping to settle down in unilateral fracture dislocation.

IMF for 4 weeks – bilateral fracture dislocation with anterior open bite.

FUNCTIONAL

Emphasis is on Active Movement – it is important on fractures which one at risk causing Ankylosis therefore movement can prevent bony union traction. Devices can be attached to mandible to remedy Distoocclusion combined with active movements.

SURGICAL

Consist of exploring condylar fragment reducing it to normal anatomic relationship and then fixing it in that position.

CONSERVATIVE AND FUNCTIONAL TREATMENT

The goal of treatment is to allow bony UNION to occur when there is no significant displacement of condyle or in case of fracture dislocation, to produce an acceptable FUNCTIONAL PSEUDOARTHROSIS by reeducation of neuromuscular pathways.

Conservative management can be as simple as observation and soft diet:

Variable period of immobilization followed by intense physiotherapy.

If patient is able to establish and maintain normal occlusion with minimal amount of discomfort – no active treatment is required.

Patient encouraged to adhere to soft diet and close supervision is mandatory for any signs of occlusal instability deviation with opening increasing pain.

Any one of the signs indicate the conversion of non displaced fracture to displaced one requiring active treatment.

Active treatment is:

IMMOBILIZATION  involving:

IMF; arch bars, cycht wires, or splints.

Period of immobilization should be long enough to allow initial union of fracture segments.

Should be short enough to avoid complications such as muscular atrophy, joint hypomobility and ankylosis.

Currently, period of immobilization ranges 7-21 days. It can be increased / decreased depending on:

Age of patient, Level of fracture, Degree of displacement, Presence of additional fractures.

Crucial aspect of post immobilization treatment:

Consist of intense active physical therapy which allows for return of mandibular range of motion, functional movements that were hindered by injury and assists in neuromuscular system in adapting to alterations in occlusion, joint position or morphology.

Following the release of IMF guiding elastics used to direct mandible to maximal intercuspation.

Guiding elastics are placed lightly during day to promote increased mobility and more lightly at night to maintain occlusion.

Once occlusion remains stable, elastics discontinued and arch bars removed.


Studies which support conservative  management:

  1. 1947 Chalmer J. Lyons published their data on 140 cases of condylar fractures with average followup range of 5 years incidence of functional disturbance was 5.8%.
  2. 1952 McLENAN followed 180 condylar fracture for 14-37 months with a complication rate of 20%.
  3. Functional disturbances such as limitation of lateral excursions. Deviation of jaw to affected side on opening clicking of joint on fractured side.

INDICATIONS FOR CONSERVATIVE MANAGEMENT OF CONDYLAR FRACTURES

Young patients with maximum remodelling potential:

  1. In young patients under the age of 12 years. Bony union and adaptive remodelling will produce a functional condyle with its head restored to glenoid fossa even in cases of severe fracture distraction. In view of excellent remodelling potential and increased hazard to 7th cranial nerve surgery is usually contraindicated.
  2. Adult dentate patients with unilateral fracture soft diet for 2-3 weeks. 4 weeks of immobilization.
  3. Intracapsular fractures : Immobilization for 7-10 days and active movement should be encouraged as soon as possible.
  4. Adult dentate patients with bilateral fracture.
  5. Edentulous patients.

SURGICAL MANAGEMENT OF CONDYLAR FRACTURES

Objective is to reposition fractured condyle on near to its anatomical location as possible.

ZIDE and KENT (1983) have outlined the indication for open reduction.

ABSOLUTE INDICATIONS FOR BOTH CHILDREN AND ADULTS

  1. Displacement of condyle into middle cranial fossa.
  2. Impossibility of restoring occlusion by closed reduction.
  3. Lateral extracapsular displacement of condyle.
  4. Invasion by foreign body (Gun Shot wounds).

RELATIVE INDICATIONS

  1. Bilateral condylar fractures associated with comminuted mid facial fractures. Mandible is treated first by ORIF to provide a stable platform on which remaining midfacial fractures are repaired.
  2. Bilateral condylar fractures associated with gnathologic problems such as retrognathia, prognathism open bite deformity.
  3. Bilateral condylar fractures in edentulous patients where splinting is impossible because of severe alveolar bone atrophy.
  4. When IMF is contraindicated for medical reasons:
  • Seizure disorders, Psychiatric problems, Alcoholism.
  • Refractory behaviour / mental retardation secondary to neurologic injury. COPD upper airway resistance from IMF.

VARIOUS APPROACHES FOR TEMPORO MANDIBULAR JOINT

1) Preauricular.   2)Endaural   3) Postauricular.  4)Alkayat and Bramley. 5) Submandibular.   6) Rhytidectomal.  7) Intraoral.

Prime determinants in selection of approach are:

  • Location of fracture, Degree of displacement.

If fracture is intracapsular

High on condylar neck – Preauricular / Endauricular approach preferred.

Advantages:

  • Better access, Greater visibility of fracture site, Ease of placement of fixation devices, Ease of manipulation of soft tissues within joint.

Disadvantages:

  • Possibility of damage to facial N, Presence of facial scar.

Fracture subcondylar – Submandibular approach. Possible damage to marginal mandibular nerve with weakness of dedpressor muscles of lower lip.

Intraoral approach:

Advantages:

  • Visualization of fracture reduction and occlusion simultaneously.
  • Minimal risk of damage to facial N.
  • Avoidance of unesthetic facial scar.

Disadvantages:

  • Limited access in highly subcondylar and condylar neck fractures.
  • Difficulty in placing certain fixation devices.

REDUCTION OF FRACTURE SEGMENT:

In case of minimal- Displacement à Reduction accomplished by manipulating proximal segment into position with hemostat.

Condylar segment is –  More severely displaced à Reduction becomes difficult because of the pull of lateral pterygoid.

Distraction of mandible on inferior direction via clamp, towel clip, or S.S. wires placed at angle aids in visualizing and manipulating condylar segment. Condylar segment is then grasped and reduced into proper location atop mandibular ramus.

Stewart ad Bowerman (1991) suggested inserting a Moule pin into condyle to assist in positioning this small fragment.

Once the fragment is reduced and secured, pin removed prior to wound closure.

METHODS OF IMMOBILIZING CONDYLE:

  1. GLENOID FOSSA-CONDYLE SUTURE

Wassmund (1935) described drilling or small hole through lateral edge of glenoid fossa and related edge of condylar articulating surface. A chonric categut future was looped through and tied.

  1. TRANSOSSEOUS WIRING

Described by Thoma (1945); Messer (1972).

  1. BONE PINS

Thoma (1945) placed pins in condylar neck and zygomatic bone which were connected with external bar and universal joint.

Archer (1975) Insertion of pins into condylar head and neck.

  1. KIRSCHNER-WIRE (K-WIRE)

Stephenson and Graham (1952) drilled vertically from main mandibular fragment avoiding inferior alveolar bundle to that it enters fracture interface and further inserted into condyle.

  1. INTRAMEDULLARY PINS

PETZEL (1982) à Use of intramedullary screw transfixing distal and proximal segments.

KITAYAMA (1989) à

  1. BONE PLATING

Robinson and Yoon (1960) à 2-hole plate.

Koberg and Momma (1978) à 4-hole plate.

Currently majority of open reduction are secured using RIGID FIXATION involving miniature bone plating and monocortical screws.

SPECIFIC TREATMENT OF CONDYLAR FRACTURES

  • Young patients with maximum remodeling potential:
  • In patients under the age of 12 years Bony union and Adaptive Remodelling will restore a functional condyle regardless of treatment.
  • Surgical reduction is contraindicated in children because of excellent remodelling potential and increased hazard to 7th cranial nerve.
  • Treatment consist of IMF for 7-10 days followed by active movement of the joint to reduce the formation of scar tissue and prevent ankylosis.
  • Ankylosis prevents anterior and inferior distraction of mandible by its soft tissue envelope. The opposite condyle deposits appositional bone along its posterior and superior aspects. This process results in shortened ramus on ipsilateral side and normal / elongated ramus on contralateral side.
    • ADULT DENTATE PATIENTS WITH UNILATERAL FRACTURE

If patient able to attain normal centric occlusion in unilateral fracture / fracture dislocation, treatment protocol consists of:

  1. Advocating soft diet for a period of 2-3 weeks.
  2. Put the patients on NSAIDS.
  • Advising patient to take care to avoid impact to another area.

If this regime is accompanied by excessive pain / if the patient not able to attain normal occlusion then IMF for 7-10 days advised.

If there is any tendency of minimally displaced fracture to be converted to fracture dislocation or if there is real risk of further trauma to the area.

Then IMF for 4 weeks should be given to ensure union in already existing good position.

  • Sometimes it is feasible to delay IMF for 48 hours during this time spasm of pterygomassetric shrig will often settle and allow a minor occlusal discrepancy to remedy itself.
  • It should be remembered that teenage patients have greater propensity or adaptive remodelling to restore a functional condyle than adult patients. This persuades operator towards more conservative regime.

Surgical reduction and fixation by bone plating for unilateral fractures is absolutely indicated in following circumstances:

  • Impossibility of obtaining adequate occlusion by closed reduction due to locking of condylar fragment / in true lateral fracture dislocation.
  • Fracture dislocation of condyle into middle cranial fossa.
    • ADULT DENTATE PATIENTS WITH BILATERAL FRACTURES
      1. If occlusion is normal then institute IMF for 3-4 weeks as the risk of converting deviated/displaced fracture to dislocation is significantly greater with bilateral fracture than with unilateral fractures.
      2. If anterior open bite is present institute 4 weeks of IMF. After this period patient taken out of fixation and carefully watch while still maintaining the means of fixation (arch bar). If relapse is found to occur then further 2 weeks of IMF instituted.
  • If degree of anterior open bite is severe at the outset of treatment / fracture has been delayed then posterior distraction by gagging open the molar regions should be considered. This overdistraction tends to stretch any developing scar tissue and reach the tendency to relapse.

Overdistraction of molars can be achieved by one of the following methods:

  1. Thickening of molar regions of cap splints.
  2. small gutta percha blocks placed between post molar teeth in combination with arch bars.

If there is tendency towards recurrence of anterior open bite after adequate period of immobilization then.

Mild traction by bands put in place for a further period of 2-4 weeks.

Absolute indication for surgical reduction are.

If there is associated comminuted midface fracture, then it is necessary to reconstitute a mandibular platform.

EDENTULOUS PATIENTS:

  • In unilateral fractures / there is reduced need for treatment on there is slight discrepancy in bite which can be compensated by prosthetic means.
  • In bilateral cases:
    • Gunning splints employed for establishing vertical dimension.
    • Patients own dentures may be modified to be used as splints by provision of cleats some means of attaching denture to underlying skeletal bases.

Splints are secured by either piriform aperture wiring / circumzygomatic wiring.

Indication for surgical reduction in bilateral edentulous condylar fractures:

  • Splint is unavailable.
  • When denture are lost.
  • When condition is too painful for prosthetic manipulation.

COMPOUND FRACTURES

  • There is risk of postoperative infection, and development of fibrous ankylosis.
  • Any lacerations in condylar area should be carefully explored, subjected to lavage and site drained, if there is a dead space to prevent hematoma formation prophylactic antibiotics are indicated.
  • If there is comminution of condylar bone, removal of non viable bone fragments indicated at the time of exploration and closure. This may even necessitate condylectomy in grossly contaminated and comminuted cases.
  • After condylectomy there is premature posterior contact on that side so short period of IMF for 10 days necessary to allow spasm of pterygomassetric sling to settle.

 

 

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Author:

I am a practicing maxillofacial surgeon working in India.

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