Transoral parotidectomy allows for the management of parapharyngeal space tumors and accessory parotid gland tumors without the need for a transfacial/transparotid or mandible splitting procedure. It is a minimally invasive approach that permits a faster recovery and with a lesser risk of facial palsy.
Key points
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Transoral parotidectomy is an alternative to invasive external approach.
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Transoral parotidectomy can be used for parapharyngeal space parotid tumors and accessory parotid gland tumors.
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Transoral parotidectomy has a zero percent risk of total facial paralysis.
Introduction
Transoral parotidectomy is a procedure that can be used to approach a tumor arising from the deep lobe of the parotid gland ( Fig. 1 ), presenting itself in the parapharyngeal space or to manage tumors arising in the accessory parotid gland ( Fig. 2 ). This article focuses on the considerations that are specific to managing accessory parotid gland tumors transorally. However, many factors will be similar in the transoral management of parapharyngeal space parotid tumors as well.
Anatomy
Invariably, if one approaches the accessory parotid gland mass via a transoral approach, there are several anatomic structures that must be considered. Although one may not encounter them all during a particular procedure, one should at least be familiar with these structures.
Buccal Fat
The buccal fat pad is not always encountered during the transoral approach to the accessory parotid gland. However, when the buccal fat enters the surgical field it can be quite alarming and frustrating to the inexperienced surgeon. The buccal fat possesses a rich blood supply. Thus, when handled improperly it is a potential source of a postoperative hematoma formation.
The buccal fat pad can mimic a “gas” in that it seems to have the ability to expand its volume to fill any size space to which it is exposed. If permitted, it will expand out of the buccal space and into the oral cavity, thus completely obscuring the surgical view. Decompression using a sterile surgical ribbon is an effective way to manage the fat pad. In some instances, partial resection may be of assistance, but often this only results in more fat extrusion.
Buccinator Muscle
The relationship of the buccinator muscle to the oral surgeon is analogous to the platysma muscle to the neck surgeon. They are both thin, pliable muscles that are unreliably prominent from patient to patient and easily disregarded as unimportant. However, they do serve as important surgical landmarks. They both serve as an indicator to the surgeon that beyond this point are important neurovascular structures. The horizontal fibers of the buccinator stretch from the superior pharyngeal constrictor muscle posteriorly, to the orbicularis oris anteriorly ( Fig. 3 ). On the lateral aspect of the buccinator run the buccal artery, vein, and the buccal branch of the facial nerve. In addition, the distal portion of the parotid duct runs superficial to the buccinator before piercing the muscle to arrive into the oral cavity. In light of the horizontal orientation of this muscle and the neurovascular structures it shields, vertical surgical incisions are to be avoided when possible.
Masseter Muscle
The masseter is a muscle of mastication that is very easily identified transorally. Its vertically oriented muscle fibers make it easy to distinguish from the buccinator muscle. The lateral aspect of the masseter serves as the floor upon which lie the accessory parotid gland, as well as the parotid duct. The parotid gland cloaks the posterior third of the masseter muscle. Identification of the anterior border of the masseter will facilitate an atraumatic posterolateral displacement of the muscle to improve exposure of the accessory parotid gland.
Accessory Parotid Gland
Cadaveric studies have shown accessory parotid glands are found in approximately 21% of the population. These small structures are typically only noted clinically in a diseased state. Accessory parotid glands were once believed to simply be extensions of the main parotid gland. They are now recognized as being separate and distinct. In a non-neoplastic state, they are small flat structures that function independent of the main parotid gland ( Fig. 4 ). Typically, the accessory parotid gland is located approximately 6 mm anterior to the anterior border of the main parotid gland. The accessory parotid gland lies on the superior–anterior aspect of the masseter muscle near its insertion to the zygoma. In the absence of pathology this gland is surgically difficult to locate owing to its lack of palpability and miniscule size.
