|Year : 2019 | Volume
| Issue : 4 | Page : 148-151
Extracapsular parotidectomy – How we do it?
Pranay Gaikwad, Cecilt T Thomas
Department of Surgery Unit 1 - General Head and Neck Surgery, Christian Medical College, Vellore, Tamil Nadu, India
|Date of Submission||20-Oct-2019|
|Date of Decision||04-Nov-2019|
|Date of Acceptance||14-Nov-2019|
|Date of Web Publication||12-Dec-2019|
Dr. Pranay Gaikwad
Department of Surgery Unit 1 – General Head and Neck, Christian Medical College, Vellore - 632 004, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Benign tumors of the parotid gland are the most common salivary tumors. Pleomorphic adenoma is the most common benign neoplasm of the parotid gland. Benign salivary gland tumors can undergo a malignant transformation, the reason for which the salivary tumors need to be excised. Pleomorphic adenomas extend their microscopic pseudopods into the surrounding capsule mainly composed of compressed normal tissue. The facial nerve traverses through the substance of the gland. Although the nerve injury could be avoided, the earlier treatment of pleomorphic adenoma with enucleation was fraught with an unacceptably high incidence of multicentric tumor recurrences. Superficial parotidectomy or excision of the portion superficial to the facial nerve evolved as the procedure of choice for benign parotid lesions. Formal identification of its trunk at the stylomastoid foramen and tracing its branches peripherally up to the facial muscles was an essential component of the procedure. With further understanding, it became evident thatsuperficial parotidectomy (SP) was overkill for small benign lesions in the superficial lobe of the gland with an unnecessary risk to the facial nerve. Extracapsular excision (ECE) of a benign parotid tumor is a procedure that has evolved in the last two decades with the recurrence rates comparable to those following SP with reduced facial nerve dissection-related morbidity. The senior author (PG) has adopted the technique for nearly a decade and has also been involved in conducting a randomized controlled trial comparing the outcomes after SP and ECE. Through this article, the authors would like to share their technique and experience with ECE.
Keywords: Benign parotid tumor, extracapsular excision, extracapsular parotidectomy
|How to cite this article:|
Gaikwad P, Thomas CT. Extracapsular parotidectomy – How we do it?. Curr Med Issues 2019;17:148-51
| Introduction|| |
Parotid surgery is a work in progress. The fact that even benign tumors recur if not properly resected has often discouraged surgeons to be conservative in resection. Thus, even benign lesions need to be treated with the established principles of oncological surgery. Preservation of the facial nerve is the basic tenet of all the surgical techniques in parotid surgery. Benign tumors of the parotid gland can be excised without compromising the oncological safety and facial nerve. As the surgeons' understanding of the parotid tumors improved, it was only a matter of time before it was realized that lesser volumes of the gland needed to be sacrificed to achieve the same results, thus giving rise to the concept of “adequate,” “limited,” or “partial” parotidectomy. The only constant that remained to dealt was to dissect and protect the facial nerve, the Achilles heel in the parotid surgery. All the abovementioned procedures still required exposure and dissection of the nerve, thus resulting in a similar incidence of the facial nerve palsy as following a superficial parotidectomy. The pioneering work by McGurk showed that the tumor could be excised without even exposing and dissecting the main trunk of the facial nerve. Thus, the paradigm shifted toward more conservative approaches when possible.
| Premise|| |
Benign tumors of the parotid gland are capsulated lesions either true or false (formed by the compressed normal tissue). Pleomorphic adenoma is a benign tumor of the gland surrounded by a pseudocapsule. It has small projections into the capsule, the pseudopods. When the tumor is enucleated from within the capsule, the pseudopods can lay trapped within the pseudocapsule. These nests of cells will eventually result in a multicentric recurrence in the tumor bed. Microscopic studies have shown that the tumor pseudopods extend from 0.1 to 1 mm into the capsule. However, the tumor often is in the proximity to the facial nerve, and nearly 60% of the SP specimens show limited enucleation of some part of the lesion. These operations were still categorized as SP while there was no tumor recurrence. Thus, to be acceptable, any new procedure should have the recurrence rate of at least equal or lower than that after an SP.
The successful outcome of any parotid surgery is gauged on the basis of the facial nerve injury and the recurrence rate. Both of these objectives are well achieved by leaving a cuff of 2–3 mm of normal tissue and with no attempt at finding or dissecting the facial nerve – the extracapsular parotidectomy or more precisely the extracapsular excision (ECE) of a parotid tumor.
Contraindications to extracapsular excision
While the ECE is an attractive operation for the small benign lesions located in the superficial lobe of the parotid gland, the patient selection for the operation is of paramount importance to avoid recurrence, the ultimate yardstick taken for the successful treatment of tumors. Some of the common contraindications are:
- High-grade malignancy – These lesions seldom have an intact capsule and tend to invade the surrounding tissue extensively with a possible vascular invasion 
- Intraparotid lymph nodal involvement – The nodal metastases within the parotid gland will not be addressed by ECE 
- Large and multicentric tumors – There is no cosmetic or functional advantage of ECE over SP when dealing with large tumors (>4 cm). It strongly recommended to identify and dissect the facial nerve in these cases. Similarly, the premise of ECE is an antithesis to the presence of multiple tumors
- Deep lobe tumors – Deep lobe tumors cannot be removed without identifying and dissecting the facial nerve that defeats the purpose of ECE
- Recurrent tumors, skin or facial nerve involvement – Such lesions are usually extensive and require a more radical approach for tumor clearance
- Sialadenitis – Surgery for sialadenitis is done rarely that often requires complete removal of the parotid gland.
| Prerequisite|| |
The procedure should be performed under an anesthesia that avoids neuromuscular blockade for nerve stimulation (if available). In addition, the procedure is best done with the use of magnification (surgical loupes/operating microscope).
The accepted indications for extracapsular parotidectomy are:
- Clinically benign and cytologically proven benign tumor in the parotid gland
- Tumor located in the superficial lobe as ascertained on imaging
- Single tumor <4 cm in size [Figure 1].
|Figure 1: 1 cm × 1 cm fine-needle aspiration cytology-proven pleomorphic adenoma|
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| Technique|| |
Preoperatively, the lesion is marked with an indelible skin ink [Figure 2]. Under general anesthesia, an incision is made along the line of the modified Blair incision in the region of the tumor. In the neck, a subplatysmal flap is raised to continue craniad, just superficial to the parotid capsule to expose the whole extent of the lesion. A “crosshair” cruciate incision is made over the parotic capsule overlying the lesion in two perpendicular axes. With sharp dissection, the parotid capsule is opened along the crosshair and retracted [Figure 3]a and [Figure 3]b. With Stevens tenotomy (dolphin) scissors, the tissue overlying the lesion is gently dissected with the aim of leaving a margin of at least 4 mm around the lesion [Figure 4]. The use of magnification during this operation cannot be too overemphasized. As with all parotid operations, the authors strongly recommend the use of magnifying loupes, at least ×2.5, for this operation. It is not infrequent to encounter one or more of the branches of the facial nerve coursing in the vicinity of the tumor. The authors utilize intraoperative nerve stimulator to identify the ramus marginalis mandibularis nervi facialis, buccal branches, or zygomatic branches of the facial nerve as an additional safeguard. If a nerve is encountered or if the tumor rests upon a branch (es) of the nerve, it is gently retracted away from the tumor using a Graham's (curved) or Cushing's (straight) nerve hook. Every effort is made to avoid capsular rupture. The tumor is removed completely along with the margin. It is imperative to inspect the specimen for the completeness of excision. Clinical photographs of the superficial, deeper aspects and incompletely bisected specimen are taken against a measuring scale to help the pathologist and for archiving purposes. Obtaining a preoperative consent for intraoperative photography is mandatory [Figure 5]. A check Valsalva maneuver is performed, and the wound is closed over a closed suction drain in two layers.
|Figure 3: A crosshair marked over the parotid fascia overlying the tumor (a) and the parotid capsule opened along the marked crosshair and retracted (b)|
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|Figure 4: Greater auricular nerve (mosquito forceps at 8 o'clock) entering the tumor (a), the former required division (b), so as to excise the tumor (c)|
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|Figure 5: Surgical specimen with a cuff of normal tissue (a) and partially bisected specimen (b) to ensure the integrity of the capsule and to exclude features of malignancy|
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| Complications|| |
Extracapsular dissection and superficial parotidectomy have comparable tumor recurrence rates while the former has lower transient and permanent facial paralysis rates. The incidence of gustatory sweating (Frey syndrome) is also reported less frequently following extracapsular dissection. However, owing to the larger volume of the remnant parotid gland, sialoceles may be more frequent postoperatively that often settle with nonoperative measures within 3 weeks.
| Our Experience|| |
In a recently concluded randomized controlled trial comparing ECE and superficial parotidectomy done by the authors (unpublished), we found that there was an increased incidence of moderate and severe facial nerve paralysis in the immediate postoperative period in patients who underwent superficial parotidectomy as compared to those who underwent ECE (not statistically significant) [Figure 6]. The rates of the positive margins associated with ECE were similar to that of superficial parotidectomy (not statistically significant). As the authors use a suction drain in all cases, none of the patients in either group had seroma formation. During the follow-up, none of the patients experienced gustatory sweating. The patients in both groups have been followed up for at least 3 years postoperatively with no recurrences noted in either group.
|Figure 6: Postoperative facial nerve function: temporal branch (a), zygomatic branch (b), rami mandibularis (c) with mild weakness (c)|
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| Discussion|| |
After nearly a half a century of the practice of enucleation of parotid tumors, advocated by Senn in 1895 and Sistrunk, the recurrence rates for benign tumors remained 20%–45%, whereas it was 90% for the malignant tumors. The basic principles of parotid gland surgery were introduced by Janes in 1940. Foremost were the goals to localize and preserve the facial nerve with complete excision of the tumor. Superficial parotidectomy is the most performed operation for benign tumors and low-grade malignancies of the gland and is the gold standard. However, this operation is not based on any oncological principles with regard to the size, margin, or location of the tumor. It is analogous to driving a thumbnail with a sledgehammer when a small lesion is located in the tail of the gland with an unnecessary dissection of the facial nerve trunk, even when the tumor is well away from it.
During limited resection of pleomorphic adenoma of the parotid gland, the recurrence rate was 1.8% if the tumor was within 1 mm of the margin. Other large series have compared ECE and superficial parotidectomy with comparable results of local recurrences between 1.5% and 1.7% for the former procedure and similar results for the latter.,
Transient facial nerve paralysis has been reported as 8% for extracapsular dissection patients and 20.4% after superficial parotidectomy. In general, both transient and permanent facial paralysis were decreased in extracapsular dissection patients.
In two large studies, Frey's syndrome has been reported between 2.7% and 4.5% after extracapsular parotidectomy as compared to 19% and 26.1% following superficial parotidectomy, respectively.,
| Conclusion|| |
ECE of benign, small parotid gland tumors located in the superficial lobe is a feasible operation that is oncologically safe organ-preserving, cosmetically superior operation in expert hands with acceptable morbidity compared to other procedures.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
This study was financially supported by the institutional research fund.
Conflicts of interest
There are no conflicts of interest.
| References|| |
Eric R. Carlson, Robert A. Ord. Textbook and Color Atlas of Salivary Gland Pathology Diagnosis and Management. Iowa, USA: Wiley-Blackwell;Iowa, USA. p. 186-7.
McGurk M, Thomas BL, Renehan AG. Extracapsular dissection for clinically benign parotid lumps: Reduced morbidity without oncological compromise. Br J Cancer 2003;89:1610-3.
Donovan DT, Conley JJ. Capsular significance in parotid tumor surgery: Reality and myths of lateral lobectomy. Laryngoscope 1984;94:324-9.
Myssiorek D. Extracapsular dissection and limited parotidectomy. Oper Tech Otolaryngol-Head Neck Surg. 2018;29:139-43.
Ghosh S, Panarese A, Bull PD, Lee JA. Marginally excised parotid pleomorphic salivary adenomas: Risk factors for recurrence and management. A 12.5-year mean follow-up study of histologically marginal excisions. Clin Otolaryngol Allied Sci 2003;28:262-6.
Albergotti WG, Nguyen SA, Zenk J, Gillespie MB. Extracapsular dissection for benign parotid tumors: A meta-analysis. Laryngoscope 2012;122:1954-60.
Xie S, Wang K, Xu H, Hua RX, Li TZ, Shan XF, et al
. PRISMA-extracapsular dissection versus superficial parotidectomy in treatment of benign parotid tumors: Evidence from 3194 patients. Medicine (Baltimore) 2015;94:e1237.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]