Journal of the Anatomical Society of India

Surgical Incisions - Their Anatomical Basis :Part 1 - Head And Neck

Author(s): Patnaik V.V.G.*, Singla R.K.* and Bala SanjusVol. 49, No. 1 (2000-01 - 2000-06)Department of Anatomy, *Govt. Medical College, Amritsar (Punjab) and Govt. Dental College, Amritsar (Pb.) INDIA.

Presented by :drg. Willy Winardi

Introduction

• 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.

• 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.

Basic Principles

• 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

Norman and Bramley (1990)

History

• Dupuytren (1834) was 1st to note the skin tension : wounds were elliptical instead of round.

• Langer (1861) : schematic representation of the lines of greatest normal skin tension for all regions of the body.

• Rubin (1948), Kraissl (1951) and Bulacio Nunez (1974) : Langer's lines tend to run parallel with skin creases, which generally are perpendicular to the action of underlying muscles. The action of these muscles would tend to pull an incision apart.

• Kruger (1989) : while giving an incision, skin should be stretched in a way that marked line of incision rests on a solid bone thereby providing a firm base for clean incision in one deft incising move.

Maxillofacial incisions for mandible :Submandibular incision

• Principles : fractures of the mandibular body and angle regions unsuitable for intraoral treatment, e.g. difficult fracture patterns such as comminuted, atrophic, and defect fractures in order to allow optimal manipulation of the fragments, good control of the lingual cortex and inferior border, and the application of the selected hardware.

• Variations : The incision can either be parallel to the inferior border of the mandible (A) or be placed in an existing skin crease (B) for maximum cosmetic benefit.

• The length of the incision depends on fracture extend and the planned internal fixation technique. Diagram shows a skin incision 2-3 cm below the inferior border of the mandible.

• Exposure : Divide the pterygomasseteric sling and incise the periosteum at the inferior border to expose the fracture site.

• Exposure offered by extraoral approaches

• The wound is closed in layers to realign the anatomic structures and eliminate dead space. A drain may be used if necessary.

Maxillofacial incisions for mandible : Risdon's incision

• Extension of the submandibular incision posteriorly toward the mastoid region and anteriorly toward the submental region. Note that the incision leaves the resting skin tension lines anteriorly.

Maxillofacial incisions for mandible : Retromandibular incision

• A vertical incision through skin and subcutaneous tissue is made, extending from just below the ear lobe towards the mandibular angle. It should parallel the posterior border of the mandible.

• Transparotid approach: dissection• The subcutaneous tissue is

undermined, exposing the superficial musculoaponeurotic system (SMAS).

• A vertical incision is made through the SMAS into the parotid gland.

• Transparotid approach: exposure• Illustration of the amount of

exposure obtained using this approach.

• Alternative: retroparotid approach• Principles

A frequently used alternative to the retromandibular transparotid approach described above is one in which the parotid gland is lifted rather than dissected through. This requires the incision to be placed more posteriorly which means that exposure of the mandible is more limited.

• DissectionThe subcutaneous tissue is undermined, exposing the superficial musculoaponeurotic system (SMAS).

• An oblique incision is made through the SMAS. The posterior aspect of the parotid gland is identified and dissection continues behind the gland.

• The gland is lifted off the masseter muscle and retracted anteriorly.

• ExposureIllustration of the amount of exposure obtained using this approach.

Maxillofacial incisions for mandible : Submental incision

• Principles :• The submental approach is used

to treat fractures of the anterior mandibular body and symphysis. These fractures can usually be approached and treated intraorally. However, depending on the difficulty or severity of the fracture, and/or the presence of a laceration suitable, an extraoral approach via the submental route may be indicated.

• Variations in incision:A) Following curvature of anterior mandibleB) Hidden in submental skin crease

• According to the anatomy and surgical preference, both techniques offer adequate access to this area.

• Dissection is carried out to the inferior border of the mandible. The periosteum is incised sharply and the flap is elevated to expose the anterior surface of the symphysis.

• Option: bilateral extension• Submental extension

The submental incision can be extended laterally to encompass both the right and left mandible by degloving the entire lateral surface of the mandible in the same way as in the submandibular approach.

• This may be necessary in complex fractures such as comminuted, atrophic, and severe bilateral fractures.

Maxillofacial incisions for temporomandibular joint :Preauricular incision

• Make the incision in a preauricular skin crease.

• Preauricular approach

• Incising temporalis fasciaMake an oblique incision parallel to the frontal branch of the facial nerve, through the superficial layer of the temporalis fascia above the zygomatic arch.

• Dissection can be carried inferiorly in a subperiosteal plane to reach the neck of the mandibular condyle.A disadvantage of this approach is that the surgeon can reach only a limited portion of the condylar neck region.

• Al Kayat and Bramley (1979) modification :

• This modification is used for a wider exposure. They recommended a question mark shaped skin incision which avoids main vessels and nerves.

Maxillofacial incisions for temporomandibular joint :Temporal approach

• A. Initial curvilinear incision in the retroauricular crease.

• B. Transection of the external auditory meatus.

• C. Retraction of the external ear anteriorly, exposing the TMJ capsule.

Maxillofacial incisions for temporomandibular joint : Postauricular incision

Maxillofacial incisions for temporomandibular joint : Intraoral approach

• Principles :• The ramus and condyle

region can be exposed via an intraoral approach by extending the standard vestibular incision in a superior direction up the ascending ramus. The incision can be altered depending on the area of the ramus/condylar process that needs exposure and treatment.

• Vestibular incision :• Make an incision through the

mucosa in the vestibule approximately 5 mm away from the attached gingiva (in the mucogingival junction), extending up the external oblique ridge.

• Insertion of the optical retractorAfter assembly of the optical retractor to its handle, insert and place it around the posterior border of the ramus.

Maxillofacial incisions for temporomandibular joint : Face lift incision

• A standard facelift incision is made through skin and subcutaneous tissues.

• Part of the preauricular incision may be hidden behind the tragus (endaural incision).

Maxillofacial incisions for zygoma :Gille's incision

• Temporal (Gillies) approach - Skin incision :

• The Gillies technique describes a temporal incision (2 cm in length), made 2.5 cm superior and anterior to the helix, within the hairline.

• Temporal (Gillies) approach - Exposure

• An instrument is inserted deep to the temporalis fascia and superficial to the temporalis muscle. Using a back-and-forth motion the instrument is advanced until it is medial to the depressed zygomatic arch.

• A Rowe zygomatic elevator is inserted just deep to the depressed zygomatic arch and an outward force is applied.

• Great care should be taken not to fulcrum off the squamous portion of the temporal bone.

Maxillofacial incisions for zygoma : Lateral eyebrow incision

• Skin incision :• An approximately 2 cm

long horizontal incision is marked within the bounds of the lateral eyebrow parallel to the hair follicles.

• The wound edges become freely moveable by the supraperiosteal dissection and are retracted over the frontozygomatic suture or the fracture area.

• Periosteal incision :• After exposure of its surface,

the periosteum is now split sharply along the middle of the superolateral orbital rim with a scalpel.

• Subperiosteal dissection of superolateral orbital rim and internal orbit quadrant

• The underlying bony structures are freed using sharp periosteal elevators.

Maxillofacial incisions for orbital : Transconjunctival incision

• Principles• Surgical routes• The typical inferior

fornix transconjunctival approach can use two different routes to access the infraorbital rim:

• Retroseptal• Preseptal

Maxillofacial incisions for orbital : Infraorbital incision

• Infraorbital incisions lie at the transition between the thin eyelid skin and the thicker cheek skin.

• They are therefore predisposed to edema and increased visibility of the scars, even when the incision runs curvilinear within the resting skin tension lines.

Maxillofacial incisions for orbital : Bicoronal incision

• Principles• General consideration

The coronal or bi-temporal approach is used to expose the anterior cranial vault, the forehead, and the upper and middle regions of the facial skeleton. The extent and position of the incision, as well as the layer of dissection, depends on the particular surgical procedure and the anatomic area of interest. The coronal approach is placed remotely in order to avoid visible facial scars.

• Access areasThe following areas can be exposed:

• Entire calvarial vault• Anterior and lateral skull base• Frontal sinus/Ethmoid• Zygoma• Zygomatic arch• Orbit (lateral/cranial/medial)• Nasal dorsum• Temporomandibular joint (TMJ)• Condyle and subcondylar region

Summary and Conclusions

• The surgical incisions are always based upon anatomical landmarks and facts, to protect certain important structures, keeping in mind the cosmetic effects.

• This is even more important in face region for obvious reasons.

• Skeletal surgery is simplified and expedited when the involved parts are sufficiently exposed.