The Role of Extracapsular Dissection for Benign Parotid Tumors

Abstract

Surgical treatment of benign parotid tumors has been debated for decades. Extracapsular dissection (ECD) differs markedly from classic surgical approaches to the parotid neoplasm because facial nerve dissection is not performed. ECD, its advantages, disadvantages, indications, and contra-indications for benign tumors with an emphasis on benign mixed tumor will be comprehensively explored in this chapter. Factors noted to favor this approach include mobility of the tumor within the gland, a thin covering of capsule and glandular tissue, and a tumor large enough to allow digital manipulation during dissection. Imaging, fine needle aspiration cytology, and neuromonitoring play a heightened role in ECD. Recurrence and permanent facial nerve dysfunction with ECD are not higher in high volume centers performed by experienced surgeons. Transient facial nerve dysfunction, Frey's syndrome, sensory deficits, and sialocele are lower with ECD. Devastating adverse outcomes of permanent facial nerve dysfunction and recurrence should be considered by the occasional and inexperienced parotid surgeon.

Reducing the morbidity of parotidectomy for benign pathology

“…26,29,30 Our study supports the hypothesis that partial parotidectomy techniques (FTD, ECD and LP) help reduce facial nerve dysfunction by limiting exposure of the facial nerve as compared to CSP and SP. 9,31,32 Of the techniques included in this study, FTD was associated with the lowest facial nerve injury rate. Koch et al 30 similarly found a significant correlation between the extent of the operation and the incidence of facial paresis (P = 0.01) and patient-perceived morbidity (P = 0.01) when comparing LP, CSP and SP.…”

“…CSP was traditionally considered the gold standard to treat and prevent recurrence, 7,9 however, many surgeons have adopted more conservative approaches such as ECD and LP for benign tumours. 1,4,9,11,14,18,24,28 The FTD technique (used in 21% of this study population) combines components of ECD, LP, and retrograde facial nerve dissection, aiming to minimize patient morbidity. In our cohort, FTD was associated with a 2.6% temporary facial palsy rate and 4% wound complication rate representing an adjusted OR of 0.19 and 0.16 respectively, compared to LP.…”

“…Similarly, in a meta-analysis of 1882 cases, Albergotti et al 33 showed that ECD was associated with a 75% reduction in transient facial paresis compared to CSP. Nerve monitoring is a valuable method of reducing nerve injury, 9 providing auditory feedback to the surgeon whenever the nerve is traumatized. 8 The previously outlined benefits of nerve monitoring are supported by this study where the use of NIM halved the odds of facial palsy (OR 0.50, P = 0.046).…”

“…3,33 FTD should only be employed in small benign pathologies 33 and techniques including ECD and FTD should only be performed by surgeons with significant experience in CSP. 4,9,38,39 Reconstructive techniques are primarily employed following parotidectomy to restore facial contour. 26 Dermofat grafts are increasingly used to reconstruct relatively small defects created following partial parotidectomy and are of value in patients who are concerned with minor aesthetic changes.…”

“…[5][6][7] In contrast, LP and ECD remove a small amount of healthy parotid tissue surrounding the tumour to reduce facial nerve injury, Frey's syndrome and the resulting contour defect. 1,[8][9][10] Focused tumour dissection (FTD) 9 represents a 'middle ground' between LP and ECD; FTD does not require identification of the facial nerve trunk but does entail identification of adjacent facial nerve branches. It is less prone to capsular disruption than ECD because a cuff of normal parotid tissue is maintained down to the level of the facial nerve.…”