Mandible

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Principles

The retromandibular approaches expose the entire ramus from behind the posterior border. They therefore may be useful for procedures involving the area on or near the condylar process/head, or the ramus itself.

There are two varieties of retromandibular approach used to access the posterior mandible. They differ in the placement of the incision and the anatomic dissection to the mandible.

The transparotid approach has the advantage of close proximity of the skin incision to the area of interest. The retroparotid approach has the advantage of not dissecting through the parotid gland.

The facelift (rhytidectomy) approach can be considered as an alternative to retromandibular approaches.

Anatomical structures
The main anatomic structures in this approach are the main trunk and branches of the facial nerve (CN VII) and the retromandibular vein.

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Exposure offered by extraoral approaches
Submandibular approach

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Retromandibular approaches

• Transparotid
• Retroparotid

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Preauricular approach

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Facelift incision (rhytidectomy)

Transparotid approach: skin incision

General consideration
Use of a solution containing vasoconstrictors ensures hemostasis at the surgical site. The two options currently available are the use of local anesthetic or a physiologic solution with vasoconstrictor alone.

Use of a local anesthetic with vasoconstrictor may impair the function of the facial nerve and impede the use of a nerve stimulator during the surgical procedure. Therefore, consideration should be given to using a physiological solution with vasoconstrictor alone or injecting the local anesthetic with vasoconstrictor very superficially.

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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.

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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.

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Blunt dissection of the parotid gland
Bluntly dissect the parotid gland parallel to the direction of the facial nerve branches and towards the posterior border of the mandible. The dissection should be anterior to the retromandibular vein.

Branches of the facial nerve may be found during the dissection. A nerve stimulator may be helpful to identify them. They should be mobilized and protected.

Once the posterior border of the mandible has been reached, an incision is made through the pterygomasseteric sling.

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Subperiosteal dissection of the mandibular ramus
A periosteal elevator is used to strip the masseter muscle from the ramus. Further dissection superiorly along the posterior border exposes the condylar process.

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Transparotid approach: exposure

Illustration of the amount of exposure obtained using this approach.

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Clinical view of the access gained.

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Transparotid approach: wound closure

The wound is reapproximated in layers for anatomic realignment and avoidance of dead space. The parotid gland capsule must be closed tightly to prevent salivary fistula.
The SMAS is resuspended.

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The skin and subcutaneous tissues is then closed based on surgical preference.

Consider anticholinergic medication (transcutaneous patch) postoperatively to decrease salivary flow and so lessen the risk of salivary fistula.

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. Rather than approaching the mandible from directly over the ramus, it is approached more posteriorly.

General consideration
Use of a solution containing vasoconstrictors ensures hemostasis at the surgical site. The two options currently available are the use of local anesthetic or a physiologic solution with vasoconstrictor alone.

Use of a local anesthetic with vasoconstrictor may impair the function of the facial nerve and impede the use of a nerve stimulator during the surgical procedure. Therefore, consideration should be given to using a physiological solution with vasoconstrictor alone or injecting the local anesthetic with vasoconstrictor very superficially.

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Skin incision
An oblique incision through skin and subcutaneous tissue is made, extending from the mastoid process to a point just below the angle of the mandible.

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Dissection
The 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.

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

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Dissection
Once the posterior border of the mandible has been reached, an incision is made through the pterygomasseteric sling.

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Subperiosteal dissection of the mandibular ramus
A periosteal elevator is used to strip the masseter muscle from the ramus. Further dissection superiorly along the posterior border exposes the condylar process.

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Exposure
Illustration of the amount of exposure obtained using this approach.

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Wound closure

The wound is reapproximated in layers for anatomic realignment and avoidance of dead space.

The SMAS is resuspended.

A suction drain may be placed.

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The skin and subcutaneous tissues is then closed based on surgical preference.