Parotidectomy is a common procedure in head and neck surgery. An appropriate incision and identification of multiple anatomical landmarks are necessary to accurately localize the facial nerve to avoid facial paralysis, a potentially devastating condition with a tremendous impact on the patient's quality of life. The most common indication for parotid surgery is benign and malignant tumors of the parotid gland. This activity reviews the evaluation and treatment of parotid disease and highlights the role of the interprofessional team in evaluating and treating this condition.
Outline the presentation of a patient with a parotid tumor.
Describe the utility of preoperative imaging and cytology for parotidectomy.
Outline key surgical steps of parotidectomy.
Explain the importance of collaboration and communication among the interprofessional team to ensure the appropriate preoperative evaluation of the patient's disease-specific and general condition in an attempt to optimize postoperative outcomes of parotidectomy.
Parotidectomy is the partial or complete removal of the parotid gland, and it may be indicated for a variety of reasons that can include inflammatory conditions, certain infectious processes, congenital malformations, and benign or malignant neoplasms. Regardless of the indication for surgery, parotidectomy is a meticulous procedure requiring experienced surgeons, particularly due to the relationship of the gland to the facial nerve. Therefore identification and preservation of the facial nerve are the most crucial steps during the procedure (second only to oncologic safety in the case of known malignancy). Emphasis is on identification because, in the vast majority of cases, preoperative prediction of the relationship of the tumor to the nerve is not possible with much accuracy unless facial paralysis is already present prior to intervention.
Anatomy and Physiology
The parotid gland is the largest major salivary gland. It is bounded by the masseter muscle anteriorly, zygomatic arch superiorly, anteromedial aspect of the sternocleidomastoid muscle inferiorly, and the external auditory canal posteriorly. The gland is divided virtually into superficial and deep lobes by the facial nerve. The superficial lobe is lateral; the facial nerve and the deep lobe extend medially into the parapharyngeal space. However, this division is not anatomical since no true embryologic or fascial plane exists between the pars superficialis and pars profunda. The parotid gland is encased by a prolongation of the deep cervical fascia, which divides into a deep and superficial layer to surround the gland. The superficial fascia extends from the masseter and SCM to the zygomatic arch. The superficial musculoaponeurotic system (SMAS) extends from the platysma to the superficial temporal fascia superiorly. It lies superficial to the parotid fascia and should not be confused with it.
The duct of the parotid (Stenson's duct) exits the gland anteriorly and follows a course approximately 1 cm inferior to, and parallel to, the zygomatic arch. After crossing the masseter, it pierces the buccinator muscle and enters the oral cavity facing the second maxillary molar. Salivary secretions of the parotid gland are more serous in contrast with the submandibular gland, which secretes a more mixed serous/mucous saliva. This is thought to explain the higher incidence of sialolithiasis within the submandibular gland.
Relevant facial nerve anatomy is limited to its extemporal portion. After leaving the stylomastoid foramen, the main trunk of the facial nerve divides at the pes anserinus (figure 1) into two divisions: the temporofacial branching into frontal, zygomatic, and buccal branches, and the cervicofacial giving rise to the marginal mandibular and cervical branches. The course of the temporal branch can be predicted using surface landmarks as described by Pitanguy et al.: a line starting from a point 0.5 cm below the tragus in the direction of the eyebrow, passing 1.5 cm above the lateral extremity of the eyebrow (figure 2). The middle branch of the facial nerve (zygomatic/buccal) can be identified at Zuker's point, which lies midway on a line drawn from the root of the helix and the lateral commissure of the mouth with a 6 mm accuracy (figure 3). Note the buccal branch accompanies Stenson's duct over the masseter muscle. The marginal mandibular branch is located immediately in a plane deep to the platysma in close proximity to the inferior border of the mandible (figure 4). Along its course, it runs superficial to the facial vessels. The retromandibular vein travels through the parotid gland just deep to the facial nerve (figure 4). Since the facial nerve cannot be detected on a CT scan or MRI, the retromandibular vein serves as a useful radiologic landmark for the superficial and deep lobs of the gland. With the advent of 3 Tesla MRI, imaging of the intra-parotid facial nerve is occasionallypossible; however, there are concerns regarding accuracy and reproducibility, particularly in the setting of parotid neoplasms.
Another structure worthy of mentioning is the greater auricular nerve (GAN), which travels parallel to the external jugular vein and splits into an anterior and posterior branch at the level of the tail of the parotid gland. Injury to this nerve leads to loss of sensation in the skin at the angle of the mandible, the side of the upper neck, and the inferior half of the external ear. Of note, preservation of the anterior branch is often impossible as it frequently overlies the tail of the parotid and physically hampers exposure of the tail of the gland while raising the skin flap. The GAN can also be used as a nerve graft in the event of a facial nerve injury.
The parotid gland contains lymph nodes in the superficial and deep lobes with a 90% to 10% distribution, respectively. The superficial group drains the pinna, scalp, eyelids, and lacrimal glands. The deep group drains the gland, middle ear, nasopharynx, and soft palate. The external auditory canal drains into both groups. This is important in the setting of sentinel lymph node biopsy, which may necessitate superficial or total parotidectomy for melanoma or other epithelial tumors of these regions.
By far, the most common indication for parotidectomy is the removal of a neoplasm. In 75% to 80% of cases, these neoplasms are benign and of primary parotid origin. Pleomorphic adenoma and Warthin tumors represent the majority of tumors, with pleomorphic adenoma representing the most common benign parotid tumor. Of malignant tumors, mucoepidermoid and adenoid cystic carcinoma are the two most common primary parotid tumors, in that order. Metastasis from a cutaneous primary represents the most common parotid malignancy in some series, notably in Australia. Chronic parotitis and recurrent sialadenitis can be served with a parotidectomy when medical treatment and sialoendoscopy fail or are unavailable. Other indications include caseating granulomas, toxoplasmosis, branchial cleft cyst, symptomatic lymphoepithelial cyst, or tuberculosis.
Every patient should be evaluated properly before surgery. History and physical exam are essential for optimal decision-making. Most patients are asymptomatic and present with an enlarging mass that was incidentally noted. Pain, if present, is not predictive of malignant histology. A fixed mass could be malignant, inflammatory, or located in the deep lobe, though even benign masses can have limited mobility owing to the dense structure of the gland parenchyma, and so has more limited predictive utility. Examination of the oral cavity is useful to rule out the involvement of the parapharyngeal space. Facial nerve function is examined and ideally is documented with photographs. Worrisome signs include facial paralysis, trismus, formication, and numbness. The neck is palpated systematically; a parotid tail lesion might be confused with a jugulodigastric node. The British guidelines recommend ultrasound-guided fine-needle aspiration cytology (FNAC) for every patient. It has an accuracy of 96% in distinguishing benign from malignant neoplasm. It is important to correlate FNAC findings with clinical ones, for example, a Warthin tumor on FNAC in a very young patient should not necessarily reassure the surgeon into advising observation; this could represent a low-grade mucoepidermoid carcinoma since typically benign tumors present at more advanced ages. Each patient's entire clinical picture must be used to make decisions, rather than any single test. Core biopsy is helpful when FNAC is not sufficient for diagnosis. It has a 96% sensitivity and 100% specificity for the diagnosis of malignancy. The role of the frozen section is not clear; however, it may be able to differentiate malignancy from benign pathology with 99% specificity reported in some studies. Similarly, the determination of surgical margins may be possible with a notable exception of the tissue directly abutting the facial nerve. This is obviously variable subject to local pathologists' expertise, and for this reason, some authors prefer to forgo frozen sections and await permanent histology, counseling patients that a second operation may be required. CT scan with contrast and MRI can both be useful for the delineation of the extent of the lesion. Most importantly, deep lobe lesions offer subtle findings on physical exam, making imaging potentially more helpful for diagnosis and preoperative planning. Static MRI parameters can help differentiate a benign from a malignant lesion with a diagnostic accuracy of 95% when accounting for well-defined margins. Dynamic contrast-enhanced MRI with its resultant time signal intensity curve has a 96.5% diagnostic accuracy for differentiating benign and malignant lesions. It can also differentiate a malignant lesion from a Warthin tumor and pleomorphic adenoma by studying the T-peak time, and this is especially useful since pleomorphic adenoma shows a cumulative malignant transformation risk of 1% per year, in contrast to a Warthin tumor that shows only a 0.3% overall risk of malignant transformation. Studying the apparent diffusion coefficient is also useful. When the cut-off value is set at 1.3 × 10-3 mm2/s and excluding lymphomas, the diagnostic accuracy for differentiating Warthin from a malignant tumor is 94.28%. This value is at 97.06% for pleomorphic adenoma. MRI sialography proved to be a very useful technique replacing conventional sialography in most centers, it can also help with the evaluation of Sjogren disease by showing sialectasis clearly. The availability of these more specialized MRI protocols may limit their utility in some centers. Neck dissection is always performed in the event of clinically or radiographically evident cervical metastasis. For a node-negative neck, recommendations are less robust, with most authors suggesting dissection of levels I to III for high-grade lesions, T3/T4 tumors, and advanced ages, since these are risk factors for locoregional recurrence. Adjuvant radiotherapy is indicated for T3/T4 tumors, close or positive margins, and perineural/perivascular invasion. Nearly all adenoid cystic carcinoma can benefit from adjuvant radiotherapy. Therapeutic radiation is acceptable when surgery is not feasible. Conventional chemotherapy has demonstrated consistently poor outcomes as a primary treatment modality in salivary gland tumors, though it has been employed in ongoing trials in a palliative setting.
The TNM staging system is frequently used for major salivary gland tumors. Aro, et al., analyzed the data of 4,520 patients from the United States National Cancer Database in an attempt the create an adapted lymph node staging system for salivary gland tumors. Mortality increased rapidly for every LN below 4 and at a slower pattern above 4. The staging system can also be criticized for encompassing all types of salivary gland tumors, while obviously, each histologic subtype behaves differently. The standard of care staging system remains the AJCC 8th edition, as of the date of this article.
Extracapsular dissection: the facial nerve is not identified; the tumor is resected with the help of a facial nerve monitor (discussion beyond the scope of this chapter), used for benign lesions that are not pleomorphic adenoma.
Partial/superficial parotidectomy: the tumor is resected with a cuff of parotid tissue while identifying and preserving the facial nerve; used for benign lesions and lymph node metastasis into the superficial lobe.
Total parotidectomy: the entire gland is removed with identification and preservation of the facial nerve. Used for aggressive malignant tumors, deep lobe tumors, sentinel lymph node excision when located in the deep lobe, vascular malformations, or in large tumors where the distinction between superficial and deep lobes is unclear.
Radical parotidectomy: the entire gland, including the facial nerve, is removed, mostly used when preoperative facial paralysis is well established, or circumferential involvement of the nerve by malignant tumor is encountered. Simultaneous nerve grafting or other facial reanimation procedures can be employed in this situation.
The patient needs to be counseled before surgery about the risk of temporary or permanent facial paralysis, the need for a suction drain, compressive dressing, and the possibility of an aesthetic contour deformity at the site of surgery.
There are no contraindications for parotidectomy as long as the patient is medically fit for general anesthesia. While there are reports of this procedure being performed under local anesthesia, this is very unusual and not routinely recommended. In certain cases, intubation might be challenging, for example, a tumor extending to the deep lobe/the parapharyngeal space or an extensive lesion invading the temporomandibular joint leading to trismus. In such situations, awake nasal fiberoptic intubation or a tracheostomy is necessary to secure the airway.
In certain conditions, parotidectomy might not be the optimal management. While most neoplasms are managed surgically, not all parotid masses are truly neoplastic. A patient with HIV and parotid swelling is more like to have intraparotid lymphoepithelial cysts and should have a detailed imaging and/or cytologic workup. Surgery is a last resort for this entity given the bilateral and progressive nature of the disease, and the higher risk of facial nerve injury. A more appropriate option in this scenario will be one of the following: observation, repeat aspiration, antiretroviral medication, sclerosing therapy, or radiation therapy.
Parotid surgery can be performed with the basic instruments set used in head and neck operations.
Bipolar is used for hemostasis.
Nerve monitoring can be done by asking a dedicated assistant to watch the face for twitches, however continuous EMG nerve monitoring has become the standard of care in many centers. This can be employed via:
Intraoperative electrophysiological facial nerve monitor (such as the Medtronic NIMS)
Handheld nerve locator (such as the CheckPoint)
Evidence in the literature suggests the following concerning electromyographic facial nerve monitoring:
It decreases the rate of immediate facial weakness in primary surgeries
Help localize the facial nerve
Mandatory in extracapsular resection where by definition the facial nerve is not identified
Offers prognostic value regarding postoperative facial nerve function
Technique or Treatment
The procedure is performed under general anesthesia with the endotracheal tube fixed to the contralateral side. The anesthesia team should be advised to avoid muscle relaxants because facial nerve function needs to be monitored. The neck is slightly extended, and the head is turned away from the operated side. Half of the face is scrubbed with an antiseptic solution with care taken not to damage the eye. Drapes are placed with care to expose the hemiface and neck. If a nerve integrity monitor (NIM) is to be used, four electrodes are placed in the area of the temporal, zygomatic, buccal, and marginal mandibular branches of the facial nerve. Most surgeons prefer the modified Blair incision starting in a preauricular skin crease, around the lobule posteriorly, and extending inferiorly into a cervical skin crease. Some amount of skin should be left around the lobule to avoid pixie-ear (or satyr) deformity. An alternative is the modified facelift incision, which starts off similar to a modified Blair incision, however, after turning around the lobule, it extends posteriorly and superiorly into the retroauricular crease to continue within the occipital hairline.
After incising the dermis and platysma, an anterior skin flap is raised in a plane between the SMAS and the superficial capsule of the parotid. A flap as thick as possible is advised to minimize the risk of Frey's syndrome as well as skin necrosis. Some surgeons advocate dissection in a plan just deep the superficial parotid fascia to further decrease the risk of Frey syndrome. Another option is to raise a supra-SMAS flap, taking care not to injure the subdermal plexus, and then raise a second, SMAS flap in the style of a facelift. This SMAS flap can then be re-attached to minimize cosmetic deformity as well as Frey syndrome. Care is taken anteriorly not to damage branches of the facial nerve that become superficial at this level.
Classically, the greater auricular nerve is sacrificed during the procedure; however, it is often possible to preserve its posterior branch. This is done by careful dissection along the nerve after its identification while raising the cervical subplatysmal flap; at the level of the bifurcation, the anterior branch is divided. If the entire nerve is to be sacrificed, this should be done as distal as possible to preserve a lengthy segment in case it is needed as a cable graft for facial nerve reconstruction (figure 4). The assistant plays a crucial role during the procedure by monitoring the face for muscle contractions even if a NIM is used, remembering the NIM and bipolar are good servants but bad masters (the surgeon should rely on direct observation before solely relying on electronic devices). Skin flaps are retracted and fixed with silk sutures or other retractive methods. Next, the tail of the parotid is dissected from the anterior border of the SCM muscle. The external jugular vein might be divided and ligated, though it can also frequently be preserved, as this might decrease bleeding during the procedure or provide a vessel for anastomosis for reconstructive flaps.
The tail of the parotid is retracted superiorly, and the digastric muscle is identified. It serves as a landmark for the facial nerve, Saha, et al., measured the distance between the insertion of the posterior belly of the digastric over the mastoid and the facial nerve trunk and found it to be around 8 mm. The posterior belly of the digastric inserts into the mastoid tip, so tissue superficial to this structure can be divided with relative impunity once the distal marginal mandibular branch has been located. Dissection cephalad to the digastric muscle might injure the facial nerve as it exits the stylomastoid foramen between the mastoid and styloid processes. The attachments of the gland to the cartilage of the external auditory canal and the SCM muscle are divided to allow rotation and mobilization of the gland, a crucial step for identification of the facial nerve. A useful trick in adults is to palpate the mastoid tip and remove the non-salivary gland tissue overlying it and attached to the parotid. This can be done safely without concerns of facial nerve injury. Doing this in children is ill-advised since the mastoid tip is not well developed, placing the facial nerve at risk. The cartilage of the external auditory canal is dissected up to the level of the tragal pointer, another landmark for identification of the main trunk of the facial nerve, which is located roughly 1 cm inferior and anterior to it. Please note that the pointer is a cartilaginous structure that can be fractured or dislocated during the dissection; this factor needs to be taken into consideration when used as a landmark for the facial nerve. At this point, the surgeon can palpate the tympanomastoid suture, which is the most reliable landmark for identifying the facial nerve main trunk. Emphasis is on palpation since it is often difficult to visualize the suture properly. It is considered the most consistent and reliable landmark for the main trunk of the facial nerve, which emerges a few millimeters deep to its lateral edge. Bushey et al. reported a mean distance between the facial nerve and the tympanomastoid suture of 4.9 mm.
At this point the surgeon should have dissected the attachments of the gland from the external auditory canal, the SCM muscle, identified the digastric muscle, the tragal pointer, the tympanomastoid suture, and is ready to begin the delicate and tedious task of identification of the facial nerve and the dissection along its branches (Figure 5). With a fine hemostat or McCabe dissector, the main trunk of the facial nerve is located and followed distally. It is important to dissect directly atop the nerve to visualize it the entire time directly. Divide the parotid tissue overlying the area of the facial nerve that has been dissected, never beyond that area. This can be done with fine scissors or an #12 blade while the glandular tissue is splayed with the hemostat. Hemostasis is ensured with bipolar diathermy and fine ties (when tightening the knots, care must be taken not to apply pressure on the facial nerve and its branches with the tightening finger). Once the pes anserinus is reached, it is advisable to visualize the entire portion of the facial nerve proximal to it to ensure that no early branching occurred. Continue dissection along the branches of the facial nerve. Unless a complete superficial parotidectomy is planned, dissect only along branches proximal to the tumor. During the process, the retromandibular vein is often encountered deep to the facial nerve. When removing the superior part of the gland, the superficial temporal artery may need to be ligated; if so, this is performed just anterior to the auricle. When dissection continues anteriorly, the parotid duct is reached and divided if necessary. Remember that the buccal branch of the facial nerve is adjacent to the duct. Eventually, the tumor is removed with a cuff of parotid tissue or the entire superficial lobe.
When removing the deep lobe of the parotid, the surgeon can remove the superficial lobe completely or simply free it while keeping it attached anteriorly, reflecting it away, and replacing it at the end of the procedure. Branches of the facial nerve are released from the tissue of the deep lobe with blunt and sharp dissection (figure 1). The tumor can be removed either through splayed branches of the facial nerve or by retracting the mass inferiorly. If this proves to be difficult or inadequate, the transcervical approach with the division of the stylomandibular ligament provides excellent exposure of the parapharyngeal space, which includes the deep lobe of the parotid. Orabi et al. managed to removed 9 out of 9 benign tumors of the parapharyngeal space by dividing the stylomandibular ligament and retracting the mandible anteriorly. Vascular structures that need to be ligated and divided when necessary while maneuvering within the parapharyngeal space can include the external carotid, deep transverse facial, superficial temporal arteries, and the retromandibular and superficial temporal veins.
Of note, when performing total parotidectomy for chronic parotitis, Stenson's duct needs to be followed up to the oral mucosa to avoid retention of any stones within a distal stump, which might lead to subsequent infection.
Benign tumors can almost always be dissected free from the facial nerve without problems. Even with pleomorphic adenoma where a certain margin is required to avoid recurrence, preservation of the facial nerve is always the rule and has only a small risk of recurrence when resected via true superficial parotidectomy. However, some malignant tumors might invade the nerve and raise the question of the sacrifice of the invaded branch. If preoperative facial paralysis exists, every attempt should be made to resect the tumor completely, even if it included the resection of a segment of the facial nerve. When no preoperative paralysis is documented, it is acceptable to shave the tumor off the nerve (R1 resection), though many authors advocate resection of the affected branches and primary cable grafting. Isolated midfacial branches might not need to be repaired because the resulting deformity is often unnoticed.
In the event of tumor spillage, when operating on a pleomorphic adenoma, the substance should be suctioned, and the site of capsule rupture closed. Some experts recommend against site irrigation since it might spread tumor cells all over the field. This spillage is believed by some to increase the risk of recurrence; however, there is no data to support this claim. The role of adjuvant radiotherapy in this setting is not clear.
Before closure, the integrity of the facial nerve is checked, and function can be assessed with a nerve stimulator. Judicious nerve stimulation is advised since excessive electric stimulation might lead to neuropraxia. Sometimes mechanical trauma induces neuropraxia, and twitches are not observed. After meticulous hemostasis, a suction drain is inserted, and the wound is closed in 2 layers.
In the recovery room, facial nerve function should be assessed as soon as possible. Some facial weakness is to be expected, particularly in total parotidectomy. This typically resolves with time so long as all branches were definitively identified and preserved, though full recovery can take many months.
The drain is left in place until the output is less than 15 to 50 cc in 24 hours. The duration of compressive dressing is variable, and some experts remove it when the drain can be removed; others insist on the importance of a compressive dressing, especially after drain removal.
Coniglio, et al., reported their experience with outpatient drainless parotidectomy. They established the viability of this approach in a properly selected patient:
Extracapsular parotidectomy with identification of selected branches of the facial nerve when needed without identification of the main trunk
Minimal SMAS disruption and reconstruction at the end of the procedure primarily
When SMAS reconstruction is not possible, grafting material was used to fill the dead space
Jaw-bra compression dressing for 48 hours and then overnight as tolerated
Hematoma: 0.9%. Meticulous hemostasis is the key to prevention, and surgical reintervention to control bleeders.
Facial paralysis: when anatomically identified and branches are known to be intact, the most probable cause of the paralysis is stretching. This is also supported by the significantly more common incidence of paresis/paralysis in total parotidectomy when compared to superficial parotidectomy. The incidence of transient paralysis is somewhere between 16.6% to 34%, and 90% will recover within 1 month; however, it could last as long as 18 months. The ability to close the eye without any corneal exposure needs to be assessed and preventive measures should be taken to prevent exposure keratitis: ophthalmic drops and ointments, ophthalmologist consultation, gold weights, and botulinum toxin are all potential treatment options in this interim.
Seroma: managed by needle aspiration and compression dressing.
Surgical site infection: prophylactic antibiotics are controversial. Extensive procedures with neck dissection +/- free flap reconstruction are at higher risk of infection and benefit from perioperative antibiotics. In more standard parotidectomy, intraoperative antibiotics are sufficient in most patients.
Frey’s syndrome: more accurately referred to as gustatory sweating. Patients report facial swelling and sweating at the site of the parotidectomy in occurrence with meals. Etiology is believed to be aberrant innervation of the sweat glands with branches emerging from the auriculotemporal nerve after their division during surgery. This provides parasympathetic innervation to the normally sympathetic-innervated sweat glands. Diagnosis is usually based on patient history, however if there is any doubt an iodine-starch test (Minor test) will confirm the diagnosis, where iodine starch placed on the affected area turns blue signaling sweat secretion. The incidence historically has been reported as high as 50 to 100%, though, with modern techniques and the use of SMAS flaps and thicker skin flaps at the time of initial elevation, this is greatly reduced and is now quite rare. Should this develop, surgical treatment options can be disappointing, with the best results obtained using SMAS and superficial temporal artery flaps as a barrier between the surgical site and the skin. Gold standard treatment now is botulinum toxin injection. Relief of symptoms is obtained for 6 to 36 months. It works at the pre-synaptic level of the neuromuscular and neuroglandular junction by blocking the release of acetylcholine.
First bite syndrome (FBS): painful spasm in the parotid region occurring at the first bite during mastication and decreasing afterward. This pain accompanies each meal usually. It is a unique complication of surgeries targeting the deep lobe of the parotid gland, the parapharyngeal space, and the infratemporal fossa. Presumed etiology is the loss of sympathetic innervation of the parotid gland, which will lead to relative parasympathetic overstimulation, resulting in the contraction of parotid myoepithelial cells. This is supported by the fact that Linkov, et al., only had one case of FBS when the entire parotid gland was removed. This case had ectopic parotid tissue left in place. Leaving the superficial lobe in place was found to carry a higher risk of FBS. Treatment is often challenging and begins with carbamazepine, which must be titrated. Most patients report improvement with time but never complete recovery. This is thankfully exceedingly rare, and really only encountered in extensive parotidectomy and extended neck dissections that violate the deep fascia of the floor of the neck, traumatizing the superior cervical ganglion.
Loss of sensation around the ear, especially the lobule, occurs frequently. Significant but incomplete improvement is expected within one year. Preservation of the posterior branch of the great auricular nerve will hasten recovery.
Amputation neuroma might occur when the GAN is transected; treatment is by simple excision.
Surgical site depression occurs proportionally to the amount of tissue resected. Reconstruction with an SCM flap is helpful, but it has the drawback of creating a defect in the neck. An autologous fat graft can also be used.
Trismus: inflammation of the master muscle, transient, and mild.
Sialocele, or salivary fistula, is the result of the communication of a salivary duct or the gland with the skin. Saliva will be excreted through the wound. The incidence of this complication is between 4% and 14%. Treatment is by applying frequent drainage and compressive dressing. Sometimes decreasing oral intake is necessary; even completion parotidectomy has been suggested. Botulinum toxin injection offers a good therapeutic outcome by blocking the salivary flow.
Medical treatment plays a minor role when it comes to the treatment of most parotid diseases, therefore surgical intervention remains the cornerstone of treatment. Parotidectomy is an intricate procedure with functional, aesthetic, and potentially oncologic considerations. Knowledge of pertinent anatomy, preoperative optimization, techniques for identification of the facial nerve, and complications will allow the surgeon to safely and effectively care for patients requiring parotidectomy.
Enhancing Healthcare Team Outcomes
Parotid surgery is an emotionally intense experience for the patient and the family, with most fearing postoperative disfigurement. Fortunately, the results are frequently excellent for experienced surgeons. It is the physician’s duty to explain clearly to the patient what to expect, tailoring such discussions to the scenario of each individual patient. A small benign lesion may less likely result in permanent facial paralysis but is most dependent upon its location within the gland itself. An extensive malignant tumor poses a significant risk for facial nerve injury. An interdisciplinary approach is crucial to success. A free flap surgeon is consulted when significant resection is expected to discuss the pros and cons of vascularized tissue reconstruction versus local flap reconstruction. Nurses familiar with head and neck surgery are the keystone to an optimal postoperative outcome. They can recognize a hematoma that needs urgent drainage, a seroma, or a salivary fistula. The role of the radiologist and the pathologist cannot be overemphasized. Preoperative delineation of the tumor by an experienced radiologist can minimize surprises during surgery and help tremendously when counseling the patient since the surgeon had a clear idea of what type of parotidectomy he will be performing. A pathologist familiar with salivary glands is essential for accurate interpretation of FNAC, which allows appropriate patient counseling and might advise and wait a see approach in some cases like a Warthin tumor. When the diagnosis of malignancy is confirmed or in the event of spillage of pleomorphic adenoma during surgery, a radiation oncologist is consulted to discuss the need for adjuvant radiotherapy.
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Total parotodectomy, main trunk of the facial nerve and its branches dissected free from the deep lobe before the excision of the latter. Asterisk on the Pes Anserinus.
Contributed by Roger Moukarbel, MD
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The course of the temporal branch can be predicted using surface landmarks as described elegantly by Pitanguy et al: A line starting from a point 0.5 cm below the tragus in the direction of the eyebrow, passing 1.5 cm above the lateral extremity of the eyebrow
Created and Contributed by Youssef El Sayed Ahmad, MD
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The middle branch of the facial nerve (zygomatic/buccal) can be identified at Zuker’s point that lies midway on a line drawn from the root of the helix and the lateral commissure of the mouth with a 6mm accuracy
Contributed by Nabil Moukarzel, MD
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Superficial parotidectomy for a benign salivary gland tumor. 1: digastric muscle 2: main trunk of the facial nerve 3: cervical branch of the facial nerve 4: marginal mandibular branch of the facial nerve 5: great auricular nerve divided distally
Contributed by Roger Moukarbel, MD
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Surgical landmarks for identification of the main trunk of the facial nerve
Contributed by Johan Fagan, MD
Bialek EJ,Jakubowski W,Zajkowski P,Szopinski KT,Osmolski A, US of the major salivary glands: anatomy and spatial relationships, pathologic conditions, and pitfalls. Radiographics : a review publication of the Radiological Society of North America, Inc. 2006 May-Jun; [PubMed PMID: 16702452]
Chu J,Zhou Z,Hong G,Guan J,Li S,Rao L,Meng Q,Yang Z, High-resolution MRI of the intraparotid facial nerve based on a microsurface coil and a 3D reversed fast imaging with steady-state precession DWI sequence at 3T. AJNR. American journal of neuroradiology. 2013 Aug; [PubMed PMID: 23578676]
So T,Sahovaler A,Nichols A,Fung K,Yoo J,Weir MM,MacNeil SD, Utility of clinical features with fine needle aspiration biopsy for diagnosis of Warthin tumor. Journal of otolaryngology - head [PubMed PMID: 31464652]
Elmokadem AH,Abdel Khalek AM,Abdel Wahab RM,Tharwat N,Gaballa GM,Elata MA,Amer T, Diagnostic Accuracy of Multiparametric Magnetic Resonance Imaging for Differentiation Between Parotid Neoplasms. Canadian Association of Radiologists journal = Journal l'Association canadienne des radiologistes. 2019 Aug [PubMed PMID: 30922790]
Abu-Taleb NSM,Abdel-Wahed N,Amer ME, The Role of Magnetic Resonance Imaging and Magnetic Resonance Sialography in the Diagnosis of Various Salivary Gland Disorders: An Interobserver Agreement. Journal of medical imaging and radiation sciences. 2014 Sep [PubMed PMID: 31051982]
Aro K,Ho AS,Luu M,Kim S,Tighiouart M,Clair JM,Yoshida EJ,Shiao SL,Leivo I,Zumsteg ZS, Development of a novel salivary gland cancer lymph node staging system. Cancer. 2018 Aug 1; [PubMed PMID: 29742277]
Wierzbicka M,Piwowarczyk K,Nogala H,Błaszczyńska M,Kosiedrowski M,Mazurek C, Do we need a new classification of parotid gland surgery? Otolaryngologia polska = The Polish otolaryngology. 2016 Jun 30; [PubMed PMID: 27386927]
Maithani T,Pandey AK,Agrahari AK, An Overview of Parotidectomy for Benign Parotid Lesions with Special Reference to Perioperative Techniques to Avoid Complications: Our Experience. Indian journal of otolaryngology and head and neck surgery : official publication of the Association of Otolaryngologists of India. 2019 Oct; [PubMed PMID: 31741970]
Bushey A,Quereshy F,Boice JG,Landers MA,Baur DA, Utilization of the tympanomastoid fissure for intraoperative identification of the facial nerve: a cadaver study. Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 2011 Sep; [PubMed PMID: 21550707]
Bovenzi CD,Ciolek P,Crippen M,Curry JM,Krein H,Heffelfinger R, Reconstructive trends and complications following parotidectomy: incidence and predictors in 11,057 cases. Journal of otolaryngology - head [PubMed PMID: 31744535]
Marchese-Ragona R,De Filippis C,Marioni G,Staffieri A, Treatment of complications of parotid gland surgery. Acta otorhinolaryngologica Italica : organo ufficiale della Societa italiana di otorinolaringologia e chirurgia cervico-facciale. 2005 Jun; [PubMed PMID: 16450773]