Extracapsular dissection of benign parotid tumors.

Abstract

Iro andZenk1 are tobecommendedon their concise and thoroughdiscussionof the role of extracapsular dissection (ED) in the surgical management of benign parotid tumors. This discussion, aswell as a reviewof the literature, supports their hypothesis that “ED isa safeand effectivesurgical technique in the management of benign parotidneoplasms.”The true challenge is howbest to incorporate this information and surgical technique into the global management of parotid tumors. Several points require consideration: the correct definitionof theavailable andhistorical techniques for addressing parotid neoplasms, close analysis of the comparisons to date, a thorough understanding of the technique as well as evaluation of the relevant complication rates, and specific pitfalls associated with ED. Finally, as noted by all authors publishing on this procedure, significant expertise is required to successfully integrate ED into practice. Enucleation andnodulectomy should remainprocedures of historical note andnot be consideredwith currentmanagement techniques. ThedefinitionofED is very specificwith the goal of complete removal of the tumor with a 2to 3-mm cuff of normal parotid tissue, if possible, andno formal identificationof thenervebefore tumor removal. Superficial parotidectomy impliesdissectionof all facial nervebranches and the removal of theentire superficial lobe; partial parotidectomy (PP) implies the dissection of only nerve branches that is required to safely remove the tumor with a cuff of normal parotid tissue surrounding it. Historically, the pendulum swung drastically away from enucleation procedures because of the high recurrence rates toward the thorough superficial parotidectomy, which advocated wide margins around tumors, yet requiredextensive facialnervedissection. Inanappropriate fashion, thependulumhas returned centrallywithdemonstration that effective control ofbenignparotid tumors canbeachieved byPP, addressingonlybranchesof the facial nerve systemthat are in anatomical proximity to the tumor and leaving amuch smaller cuff of parotid tissue around the tumor.2 Extracapsular dissection represents the continuation of this principle by advocating theremovalof the tumorwithnervedissectiononly when required. The end points for surgical management of parotid tumors are straightforward: complete tumor removal in a fashion to prevent recurrence and limitation of any facial muscular dysfunction related to nerve dissection. Minor complications include Frey syndrome, periauricular numbness, and contour deformity. The significant surgical experiences with ED indicate the nearly equitable success of this procedure compared with superficial parotidectomy regarding recurrence and final facial nerve function. Extracapsular dissection demonstrates less transient nerve dysfunction in many series, which is understandable compared with the extensive facial nerve dissection that occurs with superficial parotidectomy.3 Directly comparing ED with appropriate PP procedures would be more informative and appropriate. Tumor recurrence rates and facial nerve functionwithED must also take into account that most ED series involved significant selectionbias,with smaller,mobile, and favorably selected tumors chosen to undergo ED and tumors that did not meet these criteria preoperatively or intraoperatively removed with superficial parotidectomy. These criteria clearly indicate that for ED to be successful, appropriate technique must be joined with excellent surgical decision making. The importance of capsular exposure in themanagement ofbenignparotid tumorscontinues tobeapointofdebate.Limited tumor exposure is commonwith all parotid surgeries and is not a significant risk factor for recurrence,4whereas formal disruption and spillage of the tumor presents a risk for recurrence. The risk of potential disruption or spillage could increase with greater direct exposure of the tumor capsule– parotid interfaceduringED.For this reason,EDtechniquesused in experienced centers attempt to leave a small cuff of parotid tissue on the tumor, allowing ED to limit the welldescribed pathologic features of incomplete capsule, tumor pseudopodia, and tumor satellites. The lower ratesofFrey syndromereportedwithEDareunderstandable, butmust be placed in the context of overall patient satisfaction and quality of life. The presence of gustatorysweatingonstarch iodineevaluationorbysolicitedpatient historymustbegradedby its effecton thepatient's life if avoidanceof this limitedcomplication is tobecomeapotentialdriver for a change in surgical technique that has afforded excellent results. Similarly, issues related to contour and cosmetic appearancemust beplaced in context. Again, themajor studies comparedEDand superficial parotidectomywhich, bydefinition, involves a greater resection of benign parotid tissue. Resultant contourdeformitieswouldbegreatly lessenedwithanappropriate PP combined with simple regional tissue mobilization techniques. Clinical experiencedemonstrates successful subjective results equivalent to those noted by Iro and Zenk1 in their experience. Potential pitfalls specifically related to ED exist. The success of ED is intricately related to technological support including appropriate preoperative imaging and facial nerve monitoring, which can be variable throughout practice centers. The authors1 note that revision parotidectomy after ED would be an easier procedure with fewer potential complications compared with other interventions. After ED, identification of the main trunk of the facial nerve system as well as previouslyuninvolvednervebrancheswouldbemorestraightforward.Yet, the facial nervebranches thatwere in closeproxRelated article page 768 Clinical Review& Education Clinical Challenges in Otolaryngology