Parotidectomy

Description:

During parotidectomy, the parotid gland is removed, either partially or in its entirety. A superficial parotidectomy removes the portion of the parotid that lies superficial to the facial nerve, whereas a total conservative parotidectomy also removes the portion deep to the facial nerve. A total radical parotidectomy includes sacrifice of the facial nerve due to malignant tumor involvement. If this is the case, a nerve graft may be performed, using the great auricular nerve, the sural nerve, or cadaveric allografts (less successful but eliminates donor morbidity).

Indications for Surgery:

Definitive surgical resection is the recommended treatment for almost all benign and malignant parotid tumors. Superficial parotidectomy is indicated if the tumor is restricted to the superficial lobe of the parotid, whereas total parotidectomy is performed if the tumor involves the deep lobe.

Contraindications to Surgery:

• Medical comorbidities that would preclude surgical or anesthesia risk

Pre-Operative Evaluation:

• Fine needle aspiration (FNA) is both a sensitive and a specific test for the diagnosis of salivary gland tumors.
• Small, superficial parotid lobe tumors may proceed to surgical resection without imaging or further diagnostic studies, as results are unlikely to change operative management.
• Larger tumors, tumors that involve the deep lobe of the parotid, or growths that are clinically suspicious for malignancy may warrant evaluation by magnetic resonance imaging (MRI) to assist in surgical planning, assess local extension, and stage the neck (evaluate the nodal status of the neck).

Anesthesia:

General endotracheal

Surgical Technique:

Superficial Parotidectomy

1. The patient is placed supine on the operating table and general anesthesia is induced via endotracheal intubation.
2. The table is rotated 180 degrees, the face is prepped and draped, and facial nerve monitor probes are inserted.
3. After injection with local anesthetic, a standard modified Blair incision is made, extending from the preauricular crease inferiorly to curve around the angle of the mandible.
4. Skin flaps are elevated in a plane superficial to the parotid fascia preauricularly, and in the subplatysmal plane more inferiorly.
5. The parotid gland is separated from the sternocleidomastoid muscle, the posterior belly of the digastric muscle, and the mastoid tip.
6. The anterior branch, and often the posterior branch, of the great auricular nerve and external jugular vein are divided, freeing the tail of the parotid.
7. The fascia between the parotid and the external auditory canal is dissected. The parotid is retracted anteriorly, exposing the tragal pointer. Three anatomical landmarks are used to locate the main trunk of the facial nerve: tragal pointer, tympanomastoid suture, and posterior belly of the digastric. The facial nerve main trunk exits the stylomastoid foramen approximately 1 cm deep and 1 cm inferior to the tragal pointer. The tympanomastoid suture can be palpated as the corner between the mastoid bone and the tympanic bone (bone of the ear canal). The stylomastoid foramen is at the medial (deep) aspect of this suture. The posterior belly of the digastric is at approximately the depth of main trunk of the facial nerve. By using these three landmarks and careful blunt dissection, the main trunk of the facial nerve can be localized to a small area. If the facial nerve main trunk cannot be identified using the landmarks above, two additional techniques can be used to find the nerve. First, the main trunk can be identified in the mastoid bone by performing a mastoidectomy. Second, a peripheral facial nerve branch can be found and traced back in a retrograde fashion.
8. The branches of the facial nerve are preserved by carefully tracing the nerve from proximal to distal in a systematic fashion. The main trunk of the facial nerve splits into the upper and lower divisions at the pes anserinus. The branches are dissected either from inferior-to-superior or from superior-to-inferior. Skipping over branches can increase the risk of inadvertent nerve injury.
9. The superficial lobe of the parotid is dissected free by cutting the parotid tissue between the previously dissected nerve branch and the current nerve branch in the plane of the nerve branches. Nerve branches often adhere to the tumor requiring careful dissection to avoid damage to the nerves or the tumor capsule. The superficial lobe is freed once all of the nerve branches have been dissected.
10. The wound is irrigated and checked for hemostasis.
11. A drain is inserted in the wound bed, and the incision is closed in two layers.
12. Care of the patient is returned to the anesthesiologist for extubation and recovery.

Total Parotidectomy

1. After completion of the superficial parotidectomy, the nerve branches are carefully freed from the underlying deep lobe of the parotid gland.
2. The deep aspect of the deep lobe is freed mostly with blunt dissection from the surrounding soft tissue attachments. The internal maxillary artery and the posterior facial vein are deep to the deep lobe and may need to be transected to free the deep lobe.
3. Once the deep lobe is freed of its attachments, it can be gently removed from the surgical bed by sliding it out from under the facial nerve branches.
4. If a facial nerve resection was necessary, a nerve graft may be performed at this time.
5. The wound is irrigated and checked for hemostasis.
6. A drain is placed in the wound bed, and the incision is closed in two layers.
7. Care of the patient is returned to the anesthesiologist for extubation and recovery.

Post-Operative Care:

• The patient is admitted post-operatively.
• Diet may be started with clear liquids and advanced as tolerated.
• Drain output is monitored, and drains are removed when output has decreased sufficiently.
• If the facial nerve was resected or facial paralysis is noted, appropriate eye care measures should be taken to prevent corneal injury. Artificial tears should be prescribed hourly as needed, and a lubricating ointment and eye taping should be used at night.
• The patient may be discharged after all drains have been removed, or with one drain still in place if taught drain care.
• Antibiotic ointment should be applied to the incision three times daily.

Complications:

• Bleeding, hematoma, or seroma
• Wound infection
• Wound dehiscence or flap necrosis
• Facial paralysis
• Frey's syndrome
• Sensory deficit of the ear lobe (great auricular nerve)
• Salivary fistula
• Cosmetic deformity