Benign tumors of the superficial lobe of the parotid gland

Abstract

Tumors of the parotid gland are a rare occurrence among head and neck tumors (only 3–8%), and the vast majority are benign. Most benign tumors of the parotid gland are pleomorphic adenoma (PA), followed by Warthin’s tumor (WT) and they occur in the superficial lobe. The only reasonable treatment is considered to be total tumor removal, but the appropriate surgical approach remains a matter of controversy. Over time, it went from enucleation to superficial parotidectomy (SP) and then to extracapsular dissection (ECD). SP is often considered to be the “gold standard”; however, the risk of intraoperative damage to the facial nerve (FN) cannot be ignored. Lately, ECD – which does not expose the main trunk of the FN – has been regarded as a safe technique for the treatment of small benign parotid tumors. Patients, Materials and Methods: The study retrospectively reviewed all parotidectomies for benign parotid tumors of the superficial lobe performed in the Department of ENT, Municipal Emergency Clinical Hospital, Timişoara, Romania, between January 2014 and December 2018. The following patient data were collected: age; sex; follow-up duration; extension of the resection; use of FN monitoring and lesion features, including position, pathology, and size. Preoperative investigation protocol included a computed tomography (CT) scan to assess the size and location of the tumor helping the treatment planning. The same surgical team performed both standard SP and ECD for the treatment of these tumors. All cases were confirmed as benign parotid tumors. Recurrences of any kind and tumors involving the deep lobe of the gland were excluded from the study. All patients underwent a macroscopically complete resection of the tumor. The main outcome was the postoperative complications in the two groups. Data regarding these complications were recorded on follow-up visits at one, six, 12 and 24 months. Results: Ninety-five patients with benign parotid tumors were operated by the same surgical team at the Department of ENT, Municipal Emergency Clinical Hospital, Timişoara, between January 2014 and December 2018 but only 89 (38 men and 51 women) met the follow-up criteria and were included in the study. Sixteen (18%) patients underwent ECD, and 73 (82%) patients underwent SP as a primary intervention. The mean lesion size for ECD group was 2.0±0.9 cm and 4.2±1.7 cm in the SP group, and it was statistically significant (p<0.05). As expected, the most common type of tumor was PA but the distribution between the groups was different: in the SP group, PA represents 83% (61/73) of cases but only 44% (7/16) of cases in the ECD group. Median follow-up time was comparable in the two groups – 33±8 months for the ECD group and 39±11 months for the SP group. There were also differences between the two groups regarding the postoperative complication rate. There were significantly more transient and permanent FN paralysis, transient and permanent great auricular nerve (GAN) dysfunctions and Frey’s syndrome (FS) in the SP group. Conclusions: A comparison between ECD and SP as surgical procedures for the treatment of benign tumors of the parotid seems inappropriate as their indications do not overlap. ECD showed similar effectiveness and fewer side effects than SP and can be considered the treatment of choice for small, superficial and/or marginal tumors located in the lateral lobe of the parotid gland.