Benign Tumors of Major Salivary Glands Treatment & Management
- Author: Fadi Chahin, MD; Chief Editor: John Geibel, MD, DSc, MSc, MA more...
Indications for surgical treament of salivary gland tumors (SGTs) include a mass of the face, neck, and floor of the mouth and the presence of clinical signs of malignancy (eg, a rapid growth on a slow-growing tumor, bleeding, airway compromise due to larger tumors, and nerve dysfunction such as paresthesia). Experienced clinicians generally agree that surgical excision is indicated for all patients in whom a parotid or salivary gland enlargement develops, unless associated medical problems preclude general anesthesia. Surgical excision aids in establishing the diagnosis and in determining the treatment plan.
Eneroth et al and others have advocated the use of fine-needle aspiration biopsy (FNAB) and reported accuracy rates of 74-90%. FNAB is mainly useful for nonneoplastic masses, metastatic tumors to the parotid gland, and nonsurgical lymphomas. Only positive diagnostic results from FNAB are significant; hence the recommendation that almost all neoplasms be removed surgically.
Inflammatory infectious masses (eg, reactive, fungal) and lymphoma should be treated medically. When symptomatic, recurrent chronic gland infection (eg, parotitis) proves refractory to conservative treatments, salivary gland excision is sometimes indicated.
Management of benign SGTs includes complete removal with an adequate margin of tissue to avoid recurrences. This usually involves a complete removal of the gland in which the tumor developed. Excision is performed with general anesthesia and without paralysis. The endotracheal tube is usually positioned in the corner of the mouth opposite to the surgical field.
The key to parotidectomy is safe localization of the facial nerve at the main trunk proximal to the gland. The possibility of total parotidectomy should be includede in the preoperative plan. There should also be discussion of the potential need to sacrifice the facial nerve, with immediate grafting, cervical lymphadenectomy, and mandibulectomy.
Superficial parotidectomy remains the initial procedure of choice for benign parotid gland tumors. The incision usually starts just anterior to the ear helix, extends inferiorly below the ear lobe, and then moves anteriorly to parallel the angle of the jaw within a distance of 2 cm. Dissection is usually performed sharply down to the superficial parotid fascia. Then, the skin flap is sutured and retracted from the surgical field.
Dissection is continued to expose the remainder of the gland anteriorly and the anterior border of the sternocleidomastoid. At this location, the greater auricular nerve is identified and preserved because it carries sensation to the ear lobule and provides the best option for nerve grafting, if needed. Note that, occasionally, deep-lobe parotid tumors may displace the facial nerve to a more superficial location, where it can easily be injured.
In a parotid gland that is being operated on for the first time, a facial nerve stimulator is generally not necessary to identify the facial nerve. Rather, the surgeon should locate the main trunk of the facial nerve by using recognized anatomic landmarks. At the end of the operation, the nerve stimulator may be valuable in confirming integrity of the individual nerve branches should a transient dysfunction become an issue in the postoperative period. Proper use of the stimulator involves testing it on an adjacent muscle, such as the sternocleidomastoid, at a setting of 0.5 mA.
Submandibular gland surgery
Submandibular gland surgery is performed with the patient under general anesthesia with endotracheal intubation. Head rotation is to the opposite side of the tumor.
A 4- to 6-cm incision is made at the mastoid process and curved along the inferior aspect of the mandible, approaching the midline. The incision is taken down through the platysma, with the muscle left attached to the skin as a musculocutaneous flap. At this point, the marginal branch of the facial nerve is identified and preserved unless it is directly involved with the tumor. The nerve is located just below the muscle and superficial to the facial vessels. The safest technique is to divide the inferior aspect of the posterior facial vein and to raise the flap to the depth of the vessels and nerve.
Dissection of the gland starts at the level of the hyoid bone and the lower aspect of the gland. Identifying the digastric muscle is important because the hypoglossal nerve with the vessels runs between the gland and the digastric muscle. Dissection continues on the posterior aspect of the gland, superior to where the facial artery is located. At this level, the blood supply to the gland is ligated. The lingual nerve is visualized by anterior retraction of the mylohyoid, and the pedicle of the gland is then carefully ligated, with attention to the main trunk of the lingual nerve. Next, the Warthin duct is identified and ligated to conclude the resection.
To complete the procedure, hemostasis is ensured, a suction drain is placed (with or without an outside pressure dressing), and a cosmetic layered closure is performed.
A history of rapid growth and physical signs and symptoms (eg, facial nerve involvement) should be elicited, discussed with the patient, and documented in the preoperative evaluation chart for future reference.
Intraoperatively, involvement of the main trunk of the facial nerve or one or more of the main branches of the facial nerve may be encountered with the tumor. This finding may alter the plan, depending on the pathology of the tumor. This is precisely the reason why it is imperative to discuss the variable case presentations with the patient preoperatively and to agree on the treatment plan beforehand. A clearly written consent, with clear preoperative documentation, is essential.
Postoperatively, it is important to evaluate facial, hypoglossal, and lingual nerve function. Occasionally, transient facial nerve paresis occurs; however, it usually resolves within 3-12 weeks after surgery. Any nondissolvable sutures and drains should be removed. Alertness should be maintained for recurrence, which could present years after surgery.
Recurrence is usually caused by inadequate excision (spillage) or inoculation. The recurrence rate, as reported after a mean follow-up period of 11.8 years, is as high as 25%.
Use proper hemostasis techniques with suction drains and compression dressing to minimize the risk of bleeding and seroma.
Iatrogenic injury is usually recognized during surgery; in this scenario, it should be immediately repaired.
If the facial nerve is sacrificed because of direct tumor involvement, immediate grafting (using the greater auricular nerve or sural nerve) is required.
Transient facial nerve paralysis (paresis) takes a few weeks to resolve spontaneously but can last as long as 6 months. Direct trauma to the nerve, devascularization, or postoperative nerve inflammation is believed to cause paresis.
Frey syndrome is a known complication after parotidectomy, and manifestations range from erythema related to eating to copious gustatory sweating. The cause is believed to be an aberrant connection of the parasympathetic fibers to the sweat gland of the overlying flap of skin. To minimize the risk of postoperative Frey syndrome, raise a thick parotid flap just above the parotid fascia.
Salivary fistulae with wound healing are very uncommon.
When a submandibular gland is removed, follow surgical recommendations to avoid unintentional injury to the lingual, hypoglossal, or mandibular branch of the facial nerve.
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