VARIOUS INCISIONS IN HEAD AND NECK REGION
- Basic principles.
- General principles.
- Incisions in upper third of face.
- Bicoronal incision.
- Incisions to approach orbitozygomatic & nasoethmoid complex fractures.
- Incisions for nasoethmoid fractures.
- Incisions for orbitozygomatic complex.
- Incisions to approach infraorbital rim and orbital floor.
- Incisions in middle third of face.
- Incisions for maxillectomy.
- Incisions for parotidectomy.
- Incisions for approach to temporomandibular joint.
- Incisions in lower third of face.
- Submandibular incision.
Incisions in head and neck region are having particular importance because of presence of a large number of vital anatomic structures and also because of aesthetic reasons. Any damage to the structures such as nerves in this region should be avoided by careful planning of the incision. The scar resulting from incisions in this region, are well exposed and is not normally hidden by usual clothing. A proper planning and technique of incision and closure is the only choice to avoid such scars.
In general an incision should be
- Close to the area to be approached
- Should not involve or damage any vital anatomic structures(e.g. nerves and arteries)
- Should give excellent visual and mechanical access.
- The cosmetic deficit should be as minimum as possible
- Incision should not alter the contour of any structure.
- It should not prevent vascularity or lymphatic drainage.
- Should be placed in areas where healing is easy
For better aesthetic results the following basic concepts are used.
- The incision may be hidden inside an orifice e.g. oral cavity, nasal cavity.
- Hair bearing areas and hair lines provide coverage.
- The junction of aesthetic units are useful e. g. vermilion border, around ala of nose.
- Incisions are put in normal wrinkles, skin creases etc.
INCISIONS IN ORIFICE REGION
Incisions hidden inside orifices leave no scar and is cosmetically superb, examples are the degloving incisions used in oral cavity to expose the mandible or maxilla, rhinoplasty or septoplasty incisions placed inside nose, orbital rim and floor may be approached through conjunctival incisions.
- Post-operative alteration in the appearance of orifices e.g. altering the symmetry of nose, loss of buccal and labial sulcus depth, exposure of sclera etc.
- Limited movements of conjunctiva and lips due to scarring .
- Break up of incision lines due to movement
- Compromised asepsis
- Compromised access
- Need for special instruments
INCISIONS IN HAIR BEARING AREA
Hair bearing areas and hair lines give excellent coverage of scar giving a superior cosmetic result .It is the principle behind the use of eyebrow, bicoronal and hair line incisions.
When putting an incision in the hair bearing area
- Incision should be placed parallel to hair follicle i.e. perpendicular to skin in scalp incisions, a bevelled incision in eyebrow.
- Incision should not be placed in an hair where future balding is anticipated.
INCISIONS AT JUNCTIONS OF AESTHETIC UNITS
Junction of aesthetic units are excellent areas where scar can be concealed. This include the labio buccal groove, nasal cheek junction, lower lip cheek junction, ear face sulcus. These areas are used in Weber Fergusson incision, lateral rhinoplasty incision, nasolabial flaps, parotid and face lift incisions.
INCISIONS IN SKIN WRINKLES AND CREASES
Normal wrinkles and skin creases are another option to put incision if it is not possible to use the above mentioned areas. These wrinkles are areas where skin normally gets folded if there is no tension. These correspond to the attachment of muscle fibres or direction of collagen bundles within the dermis and subcutaneous tissues. Several such lines are described
Langer (1861) found that puncture wounds made in fresh cadavers assume a slit or oval configuration as rigor mortis progressed. The wound’s long axis found to correspond to greatest static tension of skin. Based on this Langer described some lines known as Langer’s lines and he recommended that the long axis of incision should be corresponding to these lines in order to reduce the extent of scarring.
Lines of minimum tension is another line described for this purpose. These are also known as favourable skin tension line, natural skin crease or wrinkles. Examples are forehead wrinkles, glabellar frown lines etc. they are caused by repeated bending of skin by the action of underlying musculature exerted on the skin itself or on other movable structures in head and neck. Attachment of frontalis muscle causes forehead wrinkles, corrugator supercilliary muscles causes wrinkles at glabella and the wrinkles at temporal region known as crow’s feet are caused by repeated animation of orbicularis oculi muscle.
Relaxed skin tension lines are most accepted lines for incision nowadays. These are lines that follows the furrows when skin is relaxed. Unlike normal creases these are not visible features normally, but can be formed by pinching the skin and observing the furrows and ridges that are formed. These lines correspond to the directional pull that exist in relaxed skin. The pull is determined largely by protrusion of the underlying bone, cartilage and tissue bulk that the skin covers. The relaxed skin tension line exerts a constant tension on the face when it is repose even during sleep and are altered only temporarily by muscle contraction. It is for this reason that the incisions that incisions made along the tension lines heal better than those made tangentially to tension lines.
Langer’s lines, lines of minimum tension and relaxed skin tension lines will not correspond in many region.
Borge’s(1984) study concluded that use of Langer’s lines resulted in wider scars. Relaxed skin tension line give better result than any other lines.
If natural skin crease is prominent in one site it should be used instead of relaxed skin tension line. In areas where incision have to be put perpendicular to relaxed skin tension line a running W plasty should be done.
Incisions in growing children heal with a broad scar. It is because the scar is getting stretched as the child grows.
In general the incisions should be planned well before it is made and is marked with a skin pencil or bonneys blue. The skin is stretched before putting incision. The flat side of no 15 blade is used to put skin incision. If the tip is used to put skin incision, it is difficult to control the depth. A table knife grasp is used for skin incision and a pen grasp for mucosal incision.
Langer’s incision should be cross hatched at 2 to 3 areas in order to get good approximation of wound edge at end of the procedure.
The area of the incision can be infiltrated with 1 in 1,00,000 solution of adrenaline to get vasoconstriction, to reduce oozing of blood.
Skin and subcutaneous tissue should be penetrated in one sweep if possible.
Like that in mucoperiosteal flap mucosa and periosteum should be cut in a single sweep. Always use pulling movements.
If a multi-layered exposure is to be done, each layer is incised separately and dissected out. This will facilitate layer by layer closure. The edges of the flap should not be grasped with tissue forceps, dissecting forceps or towel clip, since they will be crushed and damaged.
The skin is elastic, extensible and resilient. These characteristics vary from birth to old age.
LINES OF SKIN TENSION
Skin possesses a degree of elasticity owing to presence of elastic fibres in the dermis. The elasticity maintains the skin in a constant tension. This is demonstrated by the gaping of wounds following incision through the dermis and also by immediate contraction of skin grafts as they are removed from the donor site. Thicker the skin graft greater the amount of elastic tissues and associated contraction. The elasticity and extensibility of the skin also facilitates the shifting of skin flaps.
The lines of skin tension in the skin was first noted by Dupuytren (1832).
Langer (1861) considered that human skin was less extensible in direction of lines of tension than across them.
Practical experience has shown that wounds heal better and scars are less conspicuous when incisions are made within or parallel to natural flexion lines, lines of facial expression.
Gibson (1967) has shown that when skin is stretched, collagen and elastic fibres become aligned in the direction of the stretch. This condition exists in the lines of expression or creases of flexion. Wounds within or parallel to these lines are less subject to tension from activity of the underlying musculature that has produced the lines of tension.
LINES OF MINIMAL TENSION
In a cutaneous defect maximal contraction results in a scar (contracture) whose long axis crosses the lines of minimal tension at right angles. The lines of minimal tension are the result of adaptation to function the skin being constantly pulled and stretched by the underlying muscle and joint. The connective tissue collagen and elastic fibres are arranged in bundles that are perpendicular to the underlying muscles.
A scar parallel to the line is not subject to the intermittent pull of the subjacent muscles, hence the term ‘lines of minimum tension’. An incision placed within a line of minimum tension or parallel to it is submitted to minimal tension during healing. Borges (1973) preferred the term relaxed skin tension lines in describing these lines.
In the head and neck lines of minimum tension represent adaptation to two different types of functional mechanisms. The first type is represented by the lines of habitual expression in the face such as the lines in the forehead, eyelids and nasolabial folds and other lines of expression around the mouth. The second type, lines of skin relaxation such as horizontal circular lines in the neck that result from movements of flexion and extension.
An incision perpendicular to line of minimum tension is subjected to constant changes in tension as a result of activity of underlying musculature, hypertrophy of scar often develops. Only slightly visible scar results when incisions in the neck are made within a skin fold or crease or parallel to the fold.
LINES OF EXPRESSION
This is produced by repeated and habitual contracture of the underlying muscles of facial expression. In some regions, a number of muscles act in unison. The nasolabial fold is the area between the skin of the lip that is tightly bound to orbicularis oris and the loosely bound skin of the cheek over the buccal pad of fat. The nasolabial fold is also formed by muscular contraction of zygomaticus, levator labii superioris and caninus muscle, and in part by risorius and buccinator.
The supraorbital wrinkle lines are formed by frontalis muscle which is inserted into the skin of lower forehead.
The vertical lines in the lower part of nose are due to contraction of transverse portion of nasalis muscle. The crease lines develop radially from oral fissures. At angles of mouth, however, the combined action of quadratus labii superiorus and other muscles in this region causes the lines to blend with nasolabial fold.
The formation of lines on the lateral aspect of the chin results from the action of triangularis, quadratus labii inferiorus and mentalis muscle.
The transverse lines across the neck, located perpendicular to platysma muscle separate folds of excess skin thus permitting extension of neck.
Every individual possess the line of expression that becomes more apparent when the muscles contract. Wrinkles are less evident in young persons. However in old age, skin crease and wrinkles are more numerous because the skin through degenerative changes has lost its elasticity and become redundant. Because the skin is less elastic and also redundant in old age, it is incapable of assuming its smooth appearance at the termination of muscle contraction.
CHOICE OF SITE OF INCISION
The size and direction of an elective incision should always be chosen in relation to lines of minimal tension. Although lines of expression and flexion coincide with line of minimum tension and are the best guide to the placing of incisions. There are exceptions e.g.- submental fold.
INCISIONS IN THE UPPER THIRD OF FACE
It is an ideal incision for approach to upper one-third of facial skeleton and the anterior cranium. This extends from one temporal region to the other and involves a major part of the scalp. For putting this, it is recommended to shave the hair for only a strip of 3-4 cms where the incision is to be made. The incision begins at the upper attachment of the helix on one side and extended transversely over the skull to the opposite side. This can be curved slightly forwards at the skull following but posterior to the hairline. The incision is often extended preauricularly to provide access to the zygomatic arches.
Initially, the incision is made deeply to sub-aponeurotic areolar tissue and the flap is raised along this plane, leaving the periosteum intact. Rarely clips are applied to the edges of the flap to aid in hemostasis. The periosteum is incised about 3 cm above the supraorbital rim and then the dissection is proceeded subperiosteally. This can be proceeded until the nasoethmoid, nasofrontal and frontozygomatic region are exposed. The supraorbital neurovascular bundle is made free from the foramen by cutting them at the lower edge of the foramen.
The lateral and temporal dissection follows the outer surface of temporal fascia up-to approximately 2 cm above the zygomatic arch. At the point where the temporal fascia splits into two layers, an incision running at 45˚ upward and forward is made through the superficial layer of temporal fascia. This incision is connected anteriorly with the lateral or posterior limb of supraorbital periosteal incision . Because the frontal branch of facial nerve courses obliquely 1.5 cms lateral to the eyebrow and not more than 2 cms above the brow, the connection between the fascia and the periosteal incisions should be at least 2 cms lateral and 3 cms above the eyebrow. The posterior extension of the temporal incision of the fascia is extended to cartilaginous auditory canal.
Once a plane of dissection is established deep to the superficial layer of temporal fascia, the dissection is continued inferiorly until the periosteum of the zygomatic arch is reached. The periosteum is incised and the zygoma, frontal bone, superior and lateral orbital margins, nasal bone and part of parietal and temporal bone are exposed.
When hemicoronal incision is planned, this incision will be stopped just short of midline.
Maximum exposure of upper one-third of facial skeleton and fronto-parietal region of cranium is exposed by this incision. This helps in management of
- extensive craniofacial trauma
- correction of craniofacial deformities
- single incision allows management of facial trauma and concomitant craniotomy if indicated
- good cosmetic result
- avoids injury to facial structures
- allows harvest and placement of cranial bone grafts
The method of wide exposure of facial skeleton using bicoronal incision has been confirmed in the literature by various authors(Launtzen et al 1986, Jackson 1989, Wedgewood et al 1992)
- loss of hair due to injury to hair follicle in the incision line
- poor scar in case of male type baldness
- inadequate access to middle third of facial skeleton
- excessive haemorrhage
- potential for damage of temporal branch of facial nerve resulting in weakness of frontalis muscle
- post-operative hematoma due to wide dissection of scalp
- sensory disturbance, anaesthesia or paresthesia affecting supraorbital and preauricular regions
- trismus, ptosis and epiphora are also reported.
Various methods for hemostasis of bicoronal incisions are
- use of surgical clips
- injection of lidocaine with epinephrine
Authors John D Burgoyne and Monte S said that the surgical clips have a distressing tendency to fall off. Cautery can cause tissue necrosis and poor wound healing. They recommended a technique in which after making the incision and before making the incision, placing two rows of running locked sutured through the scalp to the level of galea, one on each side of the incision approximately 3 cm apart using 3-0 nylon suture. Authors feel that bleeding can be controlled by this method.
Incisions to approach orbitozygomatic complex fractures and nasoethmoid fractures.
ANATOMIC CONSIDERATIONS FOR PERIORBITAL INCISIONS
Skin of periorbital region is thin and having little subcutaneous tissue. This produces prominent skin creases over this region. Skin lies directly over highly vascular orbicularis oculi muscle this provides good blood supply to the skin. The skin in this region is tension free. The number and position of skin creases vary depending on tone of orbicularis oculi muscle. Main creases are upper and lower skin creases. The superior one generally follow the contour of upper lid running 8 to 10 mm above the cilliary margin where levator aponeurosis insert into the pretarsal layer of orbicularis oculi.
The lower crease runs more obliquely from lid margin 3 to 7 mm and is formed by the attachment of extension of inferior oblique muscle. The action of orbicularis oculi produces a large number of relaxed skin tension lines in this region.
Recent recommendations support more centrally placed incisions. More peripheral orbital incisions increase risk of damage to peripheral branches of fifth cranial nerve including supraorbital, supratrochlear, infraorbital, infratrochlear nerves and also the temporal and zygomatic divisions of facial nerve.
Incisions of upper lid can cause postoperative ptosis if the attachment of levator palpebrae superioris is transected.
Another important thing is lymphatic drainage. Orbit does not have any lymph node. Lymphatics from this region drains to preauricular, intraparotid nodes mainly and also to submental and submandibular nodes. Mainly these lymphatics run in a lateral direction. Transection of these due to laceration or incision will produce intractable lymphedema especially in adults.
INCISIONS FOR NASOETHMOID FRACTURES
H shaped approach
This incision was first described by Converse and Smith (1962)
Excellent exposure of nasal bridge and canthal ligaments are achieved by this approach.
Bilateral Z incision
This was described by Digman et al (1969).
Midline vertical approach
This was described by Strang (1970). Here a 2 to 3 vertical incision is made from forehead to the base of the nose. The soft tissues are undermined to reveal the medial canthal ligament.
Visibility is found to be excellent with this approach.
W shaped approach
A curved transverse incision is made across the base of the nose within a skin crease and extended on both sides upwards and laterally just below the eyebrows.
By careful blunt dissection supraorbital nerves are identified and preserved.
This approach provides excellent visibility and access for repositioning and direct plating of the various bone fragments.
This approach like H shaped approach inevitably leaves a scar across the bridge of the nose.
Bicoronal incision gives an excellent exposure for repair of fractures of nasoethmoid complex.
Frontal bone is exposed almost entirely with the upper part of the nose and access is provided to the roof, medial and lateral walls of the orbits including the zygomatic arches.
INCISIONS FOR ORBITOZYGOMATIC COMPLEX FRACTURES
Lateral eyebrow incision
This incision should not be at right angle to the skin surface, but instead at the same angle as emerging hair to avoid transection of follicle that would impair growth. Hairs need not be shaved since they provide a valuable guide for alignment during skin closure. An incision of 1.5 cm in length is adequate.
Blunt dissection is carried out through underlying muscle fibres and the periosteum is then incised and stripped away from the outer and inner aspects of zygomatic process of frontal bone and frontal process of zygomatic bone for a distance of 0.75 cm from the bony margins. There is good exposure of frontozygomatic suture.
The incision can be extended medially to give exposure of supraorbital rim, frontonasal junction.
This was described by Wright (1979).
This incision is along the orbital rim beneath the lateral eyebrow continued down to the level of lateral canthus and extended laterally on to the zygoma if necessary. It exposes the lacrimal fossa, the lateral half of superior orbit and the frontal extension of the zygoma. The curved or S shaped incision allows extensive stretching so that wide exposure can be achieved. This is used for fracture reduction, lateral orbitotomy etc.
This leaves a prominent scar below the eyebrow.
This was described by Berke (1954).
This is put in skin crease and extended several millimetres from the lateral canthus. It is commonly associated with other incisions to improve access. It gives access to frontozygomatic sutures and lateral orbital rim.
It has got poor access to the infraorbital margins and there is chance for injury to the branches of facial nerve due to lateral extension of the incision.
Medial crease incision
This was described by Katowitz (1981).
It is a modification of upper lid crease incision in which only the medial aspect of upper crease is utilised. This gives good access to medial orbital wall.
Gillies temporal incision for elevation of orbitozygomatic complex fractures
It is placed in the temporal region between the anterior and posterior diversions of superficial temporal artery.
Incision is of 2 cm length and directed upwards and anteriorly at an angle of 45°. It is carried through the skin, temporal fascia and the temporalis muscle is exposed. The elevator is passed underneath the zygoma. This leaves no scar.
Upper lid (Blepharoplasty) incision.
This is through the upper lid crease about 8 to 10 mm above the margin of upper lid. The skin is raised from the surface of tarsal cartilage and dissection proceeded below orbicularis oculi to reach superior orbital rim.
- Superior aesthetic result.
- No risk of damage to surrounding nerves.
- No risk of postoperative ptosis.
- Less damage to orbicularis oculi.
- Technical difficulty.
- Difficult to separate skin from the muscle layer.
- Chance of necrosis of thin skin flap.
- Severe post operative oedema.
Incisions to approach infraorbital rim and orbital floor.
Access to the inferior orbital margin, which can be extended, if required to the orbital floor may be gained by the following approaches.
- Infra orbital
- Supratarsal fold incision
A guiding principle for surgical approach to the orbital floor is the use of a stepped incision where each layer of tissue is divided at a different layer so as to provide a more extensive area for subsequent healing. An incision of all layers at the same level should be avoided to prevent a depressed scar. The tissue must be handled with delicate instrument.
The transconjunctival approach
- Invisible scar
- Restricted access
- Greater degree of operative dexterity required if complications are to be avoided.
Originally developed by Bourguet (1928) as a cosmetic procedure for the treatment of fat herniation in the lower eyelids this approach was developed by converse et al (1973) and Tessier (1973) for the treatment of fracture and by the latter author for the surgical correction of congenital malformations. The technique was compared with the sub-ciliary incision by Wray et al (1977) and also reviewed by Borstlap and Freihofer for the insertion of transosseus wires following fractures of inferior orbital margin.
Ilankovan (1991) describe d the existence of a periorbital envelope which separates the orbital floor and a potential post septal space as important anatomical land marks when approaching the infraorbital rim and orbital floor through this approach.
Traction sutures are inserted into the margin of the lower eyelid and the inferior conjunctival fornix is secured with a fixation suture to facilitate elevation and undermining this layer. This preliminary part of the operation is also assisted by the injection of saline and adrenaline solution, the needle being inserted initially between the conjunctiva and the tarsal plate and subsequently inserted again through the skin deep to the palpebral portion of the orbicularis oculi, but superficial to the orbital septum which is then isolated by fluid on both superficial and deep aspects. After stabilising the lower eyelid with traction sutures and elevating the conjunctiva with the fixation suture, a small incision is made 3mm below the tarsal plate on the medial aspect and in line with the punctum. This allows the introduction of the points of fine scissors so that the conjunctiva and orbital septum which are closely adherent at this point may be undermined and dissected free from the orbicularis oculi and orbital septum are divided by the scissors as far as the line of lateral canthus and a retractor such as Desmarres pattern, inserted into the wound.
The level of division is critical since if placed too low down near the fornix it will be below the fascia passing from the inferior rectus to the tarsal plate and thus allow the escape of periorbital fat. If placed too high there may be distortion of the lower eyelid.
The tissue are then separated on a plane superficial tot the orbital septum but deep to the orbicularis oculi muscle, using blunt dissection and small gauze swabs, until the orbital rim is reached. It is important to continue the dissection for about 5mm below the rim before incising the periosteum on the anterior aspect. If the periosteum is incised directly over the rim the periorbital fat will herniate through and interfere with the operation and be extremely difficult to replace when the tissues are closed. The periosteum must be clearly defined across the entire width of the orbital margin and the infraorbital nerve dissected free from any fibrous or muscular attachments.
The periosteum is now divided just above the infraorbital foramen and elevated from the lateral to medial aspect, until the rim is exposed. Retraction is maintained by means of a malleable copper strip. Further elevation of the periosteum of the orbital floor proceeds from the medial to lateral aspect using a combination of sharp dissection with a periosteal elevator in those areas away from the infraorbital groove and small gauze swabs about 1cm in size to push away the tissues where there are adhesions around nerves and vessels or comminuted fragments of bone. It is possible to dissect as far posteriorly as the anterior limit of the inferior orbital tissue but exposure beyond this point becomes progressively more difficult.
The transconjunctival approach is useful for those procedures which do not require an extensive exposure of the orbit and can be limited to the inferior margin and the anterior aspect of the floor. When there has been a major displacement of the floor or the exact extent of the injury cannot be accurately assessed before-hand a trans-cutaneous approach offers a greater degree of latitude and flexibility. Closure is effected by insertion of a few catgut sutures to approximate the periosteum, taking care to ensure that the margins are accurately apposed to one another on the anterior aspect of the inferior rim. A failure to secure this layer tissue would result in contracture and distortion of the orbital septum which in turn would lead to ectropion of the lower eyelid. The conjunctival incision may be closed with 5-0 silk either as interrupted or continuous.
The infraorbital subciliary approach:
The technique is sometimes described as blepharoplasty type of incision since it is similar to that employed for the excision of redundant skin below the lower eyelid.
It provides an excellent exposure of the entire orbital floor and the lower part of lateral and medial walls. If combined with other approaches from the outer or inner aspects of the eyebrow almost all areas can be reached with safety and without undue difficulty.
Approach is by
- Preliminary injection of local anaesthetic solution to separate tissue layers.
- Proposed path of incision is marked on the skin. Path of incision follows a line parallel to the margin of the lower eyelid. A lateral extension of the incision may be marked which inclines downwards at about 45 degrees, placed preferably in one of the skin creases which forms the lower limit of crowfoot wrinkles adjacent to the lateral canthus of the eye. Although the extension may not be required, it is better to delineate it accurately before the tissues became distorted by oedema.
- Initial incision is made in the skin alone with care taken not to penetrate the muscle layer at this stage. The lower edge of the incision is picked up by two skin hooks so as to facilitate undermining of the skin, which is done with fine blunt ended scissors. The skin is gently stretched upwards while dissection proceeds. The dissection is continued to expose the full width of operative field.
- Incision of orbicularis oculi:
- Palpation will confirm the position of the rim and just below the level the fibres of the orbicularis oculi are split transversely. Dissection then continues below this level until a point is reached about 0.5mm below the orbital margin.
- Incision of periosteum
- After identifying the infraorbital nerve and cleaning away any fibrous septa or muscular attachments the periosteum is incised down to the bone across the full width of the orbit.
- Elevation of periosteum and further dissection
- As in case of the subconjunctival approach the periosteum is elevated from the lateral aspect first and when stripping it away from the orbital rim it is better to start on the medial side.
- In the region of infraorbital neurovascular bundle, dissection with gauze swab will be useful. As the dissection proceeds tissue must be held up with special retractors, with care taken by the assistant not to exert excessive pressure upon the undersurface of the globe.
- A slight elevation of periosteum from the medial and lateral aspect will enable posterior extension of dissection. However when elevating the periosteum from the medial aspect care must be taken to avoid damage to the origin of inferior oblique muscle but the tendon can be dissected clear of periorbital tissues to a considerable extent if required and this will further aid the elevation of the globe.
- Limit of dissection:
- Posteriorly upto the anterior limit of the inferior orbital tissue.
- Laterally above the level of insertion of lateral palpebral ligament.
- Medially the anterior two thirds of orbital plate of ethmoid bone.
- More anteriorly care must be taken not to disturb the lacrimal sac and structures attached to the margin of lacrimal fossa.
- The liberation of incarcerated tissue will be facilitated by the use of traction test in conjunction with any separation of adhesions and the operator can then be satisfied that all the mechanical obstruction to ocular movement has been eliminated. Any loose fragments of bone around the margins of the defect are removed.
Advantage of subciliary incision are wide exposure and cosmetically acceptable scar.
Disadvantages include possible development of ectropion, entropion and persistent oedema of lower eyelid (This results from dissection of orbicularis oculi muscle and injury to lymphatic vessels).
In a modification of the subciliary incision by Philips et al after the usual stepped type incision to expose the fracture site and after completion of the necessary management two or three holes are drilled in the inferior orbital and the free edges of the dissected periosteum and underlying muscle is elevated and sutured to the orbital rim. Therefore the thicker skin, subcutaneous tissue are re-suspended in anatomical position. This has been claimed to further reduce the chances of ectropion.
Infraorbital subpalpebral approach
Here infraorbital incision is made 5mm below the lower lid margin through a natural skin fold. The subcutaneous dissection is extended to the lower eyelid and then deepened through the orbicularis oculi to the orbital rim. The periosteum is incised and elevated from the orbital floor. As mentioned earlier dissection is in layered manner to decrease scarring and fixation of soft tissue to bony orbital rim.
The major advantages is wide exposure. Disadvantages are a potentially visible scar, ectropion and entropion.
Supratarsal fold incision
The incision is placed in skin fold parallel to superior palpebral sulcus above the tarsal plate( 10 to 14 mm above the anterior margin of upper lid). A 2 cm incision is usually adequate. It can be extruded medially or laterally into the crows fold skin crease. With a modest skin flap raised orbicularis oculi is separated by blunt dissection. Care is taken not to perforate the underlying orbital septum. The dissection continue superiorly and laterally to the periosteum of orbital rim. This is incised sharply to expose supraorbital rim and zygomaticofrontal suture. The dissection can be carried into the temporal fossa posterior to the frontal process of zygoma to provide access for elevation of the zygomatic complex.
INCISIONS IN MIDDLE THIRD OF FACE
INCISION FOR MAXILLECTOMY(Fergusson’s incision & its modification).
The classical exposure of the maxilla used the Fregusson’s incision and this incision with its modification are still the incision being used for maxillectomy.
This incision runs vertically through the centre of the upper lip from the red margin to the base of the columella. An equally good result can be obtained by following the philtral prominences. At the base of the columella, the incision turns horizontally running in the angle between the nose and the lip, the cheek around the alar base. Then the incision turns up along the side of the nose almost to the inner canthus. Before actually putting the incision, its line should be drawn with Bonney’s blue and matching points tattooed for subsequent suturing.
From the inner canthal area the classical Fergusson’s incision runs laterally across the lower eyelid at a distance from the lid margin. The placing of the incision in this line is recognised to result in intractable lymphoedema of the eyelid. To avoid this a modified version is used which runs parallel to and 2 to 3 mm from the lid margin. The skin of the eyelid is elevated as a part of the cheek flap leaving the greater part of orbicularis, the tarsal plate and the conjunctiva in-situ.
The upper lid is divided in full thickness and the incision is continued backwards along the upper buccal sulcus to the maxillary tuberosity. The cheek flap is then elevated off the underlying maxilla.
Thus the Fergusson’s incision in its classic and modified form gives a wide exposure. If orbital extension operation is carried out along with maxillectomy the incision can be further extended to encircle the lid margins.
INCISIONS FOR PAROTIDECTOMY
Incisions to approach the parotid region are complicated by the presence of facial nerve. The main trunk itself or the cervical and marginal mandibular branches may be involved in the incision. Therefore the incision in this region should be placed in an area where
- there is no risk of damage to the facial nerve.
- Should give acceptable access to the superficial and deep lobe of parotid gland.
- The scar resulting from this should be aesthetically acceptable.
In general all incisions for access to parotid should have
- A preauricular part that extend from variable distance from upper attachment of helix to the ear lobe.
- A retroauricular portion following the posteroinferior portion of auricle.
- A cervical extension that extends to a variable distance to the mastoid region
- A submandibular part along the submandibular crease.
The facial nerve after emerging from stylomastoid foramen enters the gland through its posteromedial surface and comes anteriorly and laterally to divide in the plane of superficial and deep lobe of the gland. This level correspond to the infratragal notch of the auricle. So incision in this region should involve only skin and subcutaneous tissue.
For proper identification of the facial nerve it is appropriate have a blood less field for which either use of hypotensive anaesthesia is preferred or injection of epinephrine into the incision and operative site between the tragus and the posterior belly of digastric.
The original Blair incision began superiorly paralleling the last centimetre of the zygomatic arch then turned sharply inferiorly passed anterior to the ear and continued into the neck along the anterior border of the sternocledomastoid muscle.
In the Triple modified Blair incision the part paralleling the zygomatic arch has been eliminated. The incision begins superiorly immediately anterior to the helical rim passes between it and the tragus continues inferiorly on the posterior surface of the tragus curves anteriorly between the tragus and the lobule, curves posteriorly under the lobule to the mastoid process, then curves gently inferiorly to pass into neck in a natural wrinkle if one is present in an appropriate location. The flap is elevated sharply to the anterior border of the gland to expose the operative field.
The structures that surround the gland command more attention than details of the gland itself. The structure that commands the most attention is the facial nerve. The only constant location of the facial nerve is at the stylomastoid foramen posterior and lateral to the base of the styloid process. This is the preferred location to attempt identification of the nerve.
At a point approximately two thirds of the distance from the angle of the mandible the temporomandibular joint, the main trunk divides into temporofacial and craniofacial branches. More distal branching is highly variable and the peripheral branches often are not in the same parasagittal plane with superior branches more superficial than the inferior branches. The nerve is surrounded by a thin sleeve of connective tissue allowing separation of the gland from the nerve. Mobilisation of the posterior surface of the gland is the key to rapid identification of the nerve. The gland is first separated from the cartilaginous and bony ear canal by blunt dissection following tragal perichondrium until the styloid process can be readily palpated.
Next the gland is separated from the anterior border of the sternocleidomastoid muscle and this separation requires division of the anterior branch of the greater auricular nerve. If this occurs this can be dissected out and save for use as nerve graft in repairing the facial nerve if resection of part of the facial nerve is anticipated.
The gland is reflected forward until the posterior belly of digastric can be seen. The main facial nerve trunk ties within a triangle formed by the tragal cartilage (posterior): the posterior belly of the digastric and the styloid process. The dissection should thus continue toward the styloid process from the tragal pointer and the digastric. The main trunk is usually greater than 1 cm deep to and slightly inferior to the tragal pointer and is surrounded by a small amount of fat – a warning of its proximity.
An alternate technique is to follow the tympanomastoid suture medially. The main trunk of the facial nerve will be found 6 to 8 mm deep to its drop off point.
In rare situation in which the main trunk cannot be safely approached there are six optional approaches. Five of these involve identification of peripheral branches and following it retrograde to the main trunk. The buccal branch is parallel to and 1 cm inferior to the zygomatic arch and slightly superior to the parotid duct.
The marginal mandibular branch can be found by carefully dissecting along the deep surface of the tail of the gland. Temporal and zygomatic branches can be located by careful dissection along the zygomatic arch.
The cervical branch can be located by dissecting along the posterior deep surface of the tail of the gland. Finally the posterior facial vein can be located inferior to the gland and followed superiorly until the cervicofacial branch crosses it superficially.
The sixth method involves partial removal of the mastoid process to identify the main trunk prior to its exit from the temporal bone.
Once the main trunk is identified the operation becomes a branch by branch dissection of the nerve using fine tipped haemostat.
Other incisions described for access to parotid are
- Adson and Ott described a Y shaped incision with smooth angles. Thus composed of a preauricular incision starting from upper attachment of helix. The incision is brought downwards and below the lobule of the ear to reach the anterior border of sternocleidomastoid muscle just below the mastoid process. From this point incision is carried downwards and forwards along the anterior border of sternocleidomastoid muscle behind mandibular angle. Then a postauricular incision is made along the junction between skin and auricle and is joined with the preauricular part below the ear lobule.
- In Guteirrez incision there is a temporal extension.
- In Redden’s modification temporal extension is avoided. The extension to mastoid process is lower than that of other incisions. The post auricular part is away from the ear lobule.
- Samengo (1961) described a Y shaped incision with superior aesthetic result. It involves straight incision lines.
- Apprani (1984) suggested another incision. This includes a temporal component that extends anteriorly and upwards in hair line, a preauricular portion running downwards to the lower end of helix, a postauricular portion behind the helix that smoothly curves over the mastoid process. This incision is almost completely hidden in hair bearing area.
- Jose Juis Ferreria (1990) described a modified approach to parotid region. The incision comprises a temporal, preauricular, sublobular, retroauricular, mastoid and cervical sectors. The temporal portion extend above the upper attachment of helix and curves gently forwards but limited to hair bearing area. The sublobular sector encircles the lobe, following its contour. The retroauricular portion ascend behind the ear approximately halfway up to the posterior auricular groove where it begins to curve gently backward towards the mastoid process and there the incision becomes concave and course downwards and forwards along the nape of the neck. The cervical sector is arcform and run approximately 1 cm within the hair line. It is slightly concave and ends at the level of an imaginary line projecting from the lower edge of mandible into the lateroposterior cervical area.
According to the authors there is decreased chance of impaired circulation wound dehiscence and formation of parotid fistula. Access is excellent and hidden in hair bearing area, so aesthetically superior.
Complication of incision for access to parotid region
- Potential for facial palsy
- Potential for Frey’s syndrome
- Keloid over cervical and mastoid region
- Oedema of ear lobule
- Salivary fistula
- Numbness in temporal region
- Loss of hair in temporal region
INCISIONS FOR APPROACH TO TEMPOROMANDIBULAR JOINT
Approach to TMJ is done by following incisions
- Preauricular (Rowe-1972).
- Postauricular (Alexander and James-1975).
- Endaural (Davidson-1975).
- Intraoral (Sear-1975).
- Temporal (Alkayath & Bramley-1979).
- Submandibular (Risdon-1934).
This is commonly and widely used. It is placed in a skin crease formed by external ear with facial skin. Incisions start at the level of lower border of tragus and running upwards around the external auditory meatus then around the upper attachment of helix. From this point incision is curved upwards and forwards approximately by 1cm. The total length of the above incision is little more than 4 cm. The junction of the upper and lower curved incisions forms a sharp point of skin just anterior to external auditory meatus. This corner is picked up by a skin hook so that tension can be maintained in the flap during the next stage of dissection.
For better access Rowe (1972) modified the incision by angling the upper relieving incision upwards and forwards at 45º from the point of attachment of the helix lying within the hair bearing area over the temporalis muscle extending if necessary for a further 4 cm. This allows a more extensive superficial flap to be raised and may avoid a traction injury to the upper branches of the facial nerve when wide access is required. Henry (1969) gains access to the joint through a short vertical preauricular incision.
The incision is deepened by blunt dissection first through the insertions of the preauricular muscles and then following the anterior wall of the cartilaginous auditory meatus, which runs slightly downwards, forwards and inwards. The base of the zygomatic arch is identified to the temporomandibular joint. Usually the superficial temporal artery and vein will lie in the tissues anterior to the dissection and are retracted forwards within the flap, should they be encountered. They may be ligated and divided. The main requirement at this stage is to identify the root of zygomatic arch. The periosteum over the root of the zygomatic arch is opened using a vertical incision and a subperiosteal tunnel is created along the outer side of the zygomatic arch, blunt dissection of the periosteum must be employed because sharp dissection can increase risk of damage to facial nerve. Further blunt dissection will reveal the outer wall of the capsule below the zygomatic bone and will reveal the forward and downward sweep of the margin of the glenoid fossa as it runs to the articular eminence. The blunt dissection can be extended anteroinferiorly to expose the anterior part of the capsule and below it’s attachment the condylar neck.
As dissection continues to expose the periosteum margin, capsule profuse venous haemorrhage may occur that is controlled by temporary pressure. The plane of dissection should be confirmed regularly by manipulating the movement of the condyle.
Alkayat and Bramley (1979) suggested a temporal extension of the preauricular incision in the form of a question mark facing forwards. Their modification was based on study of 56 cadavers to identify the relationship of upper branches of facial nerve to the zygomatic arch. The curved part of the question mark of the incision is carried through the skin and superficial fascia to expose the temporal fascia. The full depth of the superficial fascia is reflected with the resulting skin flap.
By blunt dissection downward, the split in the temporal fascia is identified. This is about 2 cm above the zygomatic arch. Now further dissection of the superficial fascia from the temporal fascia is performed.
Commencing at the root of the zygomatic arch, a further incision is made running upwards and forwards through the superficial layer of temporal fascia and once inside this pocket, periosteum on the upper border of the zygomatic arch may be safely incised and turned forwards. It retains continuity with the superficial flap.
The pocket between superficial and deep layers of temporal fascia can be extended as far anteriorly as the frontal process of the zygomatic bone and posteriorly continuous with preauricular incision placed just anterior to external auditory meatus. Wide exposure of TMJ is possible with this technique without excessive traction on the anterior flap thus avoiding injury to the facial nerve. The upper part of the incision gets disguised in the hair bearing area.
This was described by Davidson (1955) in which skin incision passes downwards and backwards in the cleft between the helix and the tragus and proceeds along the roof of the external auditory canal for approximately 1 cm. The incision is then reversed at the anterior half of the meatal circumference, and at the junction of cartilaginous and bony meati. At this stage, the anterior meatal wall and all the overlying tissues are reflected forwards in much the same way as has been described. The main advantage claimed for this incision is that the scar is hidden, but the access is poor.
Here the incision is made in the groove between the helix and the post-auricular skin so that the entire ear can be reflected forwards after completely dividing the cartilaginous external auditory canal. Advantages include wider exposure and better cosmetic result.
Disadvantages are partial stenosis of auditory canal, possibility of infection and necrosis of auricular cartilages with resultant deformity of pinna.
A modification of post-auricular approach does not involve the division of cartilaginous auditory meatus. It is appropriately described as circum-meatal approach in which components of pre-auricular and post-auricular incisions are incorporated.
The skin incision anterior to the ear commences at the upper border of the tragus and passes upwards in the pre-auricular crease to reach the most superior attachment of the helix to the scalp at which time, the knife blade cuts right down to the underlying bone so that a full-thickness incision including the periosteum is made. This is completed by carrying it backwards and downwards around the outer margin of the funnel-shaped bony auditory meatus to terminate just above the commencement of the mastoid process. The superior and post-auricular muscles are divided in the upper part and brisk bleeding may be experienced that is readily controlled by diathermy.
The tissues posterior to the ear are elevated and sub-periosteal blunt dissection is done to free the cartilaginous auditory meatus from the auditory canal and retract it downwards.
Anteriorly, blunt dissection is done as in the pre-auricular approach to expose the later al aspect of the capsule.
The incision starts at the level of the upper occlusal plane, carried downwards along the external oblique ridge and then down along the mandibular body.
The upper tissues are freed by sub-periosteal retraction and a forked ramus retractor is used to pull them upwards. Further sub-periosteal dissection is extended backwards until the neck of the condyle is exposed and then by vigorous blunt dissection and detachment of lower head of lateral pterygoid as much as possible. Gutter-shaped retractors are used to protect the soft tissues. By this approach, accessibility is poor.
It is similar to that for an ideal submandibular incision. Masseter muscle can be reflected off the lateral surface and medial pterygoid on the medial surface. Appropriate retraction exposes the ramus and the neck of the condyle.
Kasey and Feodor et al have described a combination of pre-auricular incision and a middle fossa craniectomy just above the glenoid fossa for access to the tumours of the glenoid fossa.
INCISIONS IN LOWER THIRD OF FACE
- Treatment of fractures of the mandible
- Ramus osteotomies
- Surgical approach to TMJ
- Surgical approaches to submandibular gland
- Drainage of submandibular and sublingual abscesses
- Soft tissue aesthetic surgery as in masseteric hypertrophy
- Removal of submandibular lymph nodes.
The major structures in the way of the incision are
- Marginal mandibular nerve and the cervical branch of facial nerve,
- Facial artery
- Facial vein
Marginal mandibular nerve leaves the antero-inferior part of the parotid gland and runs anteriorly first at the level of the lower border of the mandible. The position of the nerve can vary. In some individuals, it runs just below the mandibular border and ascends over the body at the canine region. To avoid damage, submandibular incision should be placed 2 mm below the lower border of the mandible.
The cervical branch runs downwards just posterior to the ramus. This nerve lies superficial to deep cervical fascia in the platysma muscle. Therefore the incision should include the platysma.
The facial vein lies superficial to the deep fascia and is often divided when the ramus is approached.
The facial artery lies below the submandibular gland curving round and appearing at the lower border and the antero-inferior angle of the masseter muscle. The artery is sectioned at this region.
A skin crease in the submandibular region is marked 2cm or 2 finger breadth below the mandibular border by making the skin relaxed. The anterior and posterior extension slightly vary depending on the region to be exposed. The skin in the area is stretched by extending the head and turning to the opposite direction. Incision is marked either with skin pencil or back of the blade. One or two cross-hatching should be done in order to facilitate proper closure. Then the region is infiltrated with vasoconstrictor. Initial incision should cut the skin and subcutaneous tissue perpendicular to the skin surface to expose the platysma. The tissue is undermined by blunt dissection. After this, the platysma is sectioned at the same level to expose the deep cervical fascia (to avoid damage to marginal mandibular nerve). Then at this plane, the blunt dissection proceeds upwards to reach the lower border where the deep fascia and periosteum is divided. The facial artery will bulge slowly. Then it is clamped, ligated and sectioned.
The incised periosteum can be reflected to expose the mandible. The masseter muscle can be stripped off the lateral surface and the medial pterygoid off the medial surface. With appropriate retraction, the sigmoid notch, the condylar neck, l the lower part of the coronoid process and the anterior border of the ramus may all be exposed.
Advantages of submandibular incision are its wide use when mouth opening is limited, when better exposure and accessibility is required and when intra-oral approach becomes a difficulty in the management of fracture of the angle of the mandible.
Disadvantages are possibility of an unacceptable scar, chances of injury to marginal mandibular nerve resulting in absence of movements at the ipsilateral corner of the mouth.
Risdon’s incision is described for the submandibular approach to the condyle and TMJ. This incision lies just posterior to the standard submandibular incision about one finger breadth below the angle of the mandible. The incision is curved along the angle of the mandible.