Complications of Parotid surgery: A study in 60 cases

Objective: To evaluate the common complications following parotid surgery. Material & methods: A retrospective study was done from January 2011 to December 2019 in the Department of ENT & Head Neck Surgery, Enam Medical College & hospital, Savar. Sixty (60) patients with both benign & malignant parotid disease underwent surgical treatment was selected for this study. All cases were diagnosed preoperatively by Fine Needle Aspiration Cytology (FNAC). Patients with preoperative facial nerve palsy were excluded from this study. Patients were followed up for six months and per operative & postoperative complications


Introduction:
Salivary gland tumors represent 3-10% of all head and neck neoplasms 1 . These tumors occur predominantly in major salivary glands 2,3 . The parotid gland is affected most often, ranging from 36.6% to 83%. Malignant tumors are a minority, occurring in 15-32% of cases 1,4,5 . The most common malignant and benign tumors are the mucoepidermoid carcinoma and the pleomorphic adenoma, respectively 6,7 . The pleomorphic adenoma comprises 45-60% of all salivary gland tumors. Approximately 80% occur in the parotid gland, usually in the inferior pole of the superficial lobe; however, less frequently, it can occur at the deep lobe or in the accessory parotid tissue 8 .
Benign parotid tumors present as painless, welldefined, mobile lesions, of firm-elastic consistency, with slow growth, without alterations of the overlying skin, remaining asymptomatic for a long period of time. Dysphagia may be present in deep lobe parotid tumors or in cases of parotid tumors with extension in the parapharyngeal space. A significant proportion of malignant tumors exhibit a clinical picture difficult to differentiate from benign tumors, especially in the early stages of evolution. Alarm signs and symptoms of malignant parotid tumors are pain, rapid growth with surrounding tissue invasion, ulcerations of the overlying skin, pathological cervical adenopathy, facial nerve palsy, otalgia, weight loss, and reduced appetite 25 .
The surgical treatment planning varies according to the histological type of parotid tumor. Surgery for malignant tumors must follow the oncological principles, while benign lesions require less invasive surgical treatment 26 . For this reason, preoperative diagnostic classification of parotid lesions into benign or malignant type is of paramount importance. Since biopsy is banned for the parotid territory, because facial nerve injury and permanent salivary fistulae pose a severe risk to the procedure, the preoperative imaging diagnosis supported with cytologic investigation becomes the key element of optimum management. Several surgical approaches have been described to treat this tumor. In 1895, Senn described enucleation as the technique of choice. However, tumor removal was incomplete with an unacceptable rate of recurrence. 8 Total parotidectomy removes all gland tissue lateral and medial to facial nerve, whereas superficial parotidectomy removes parotid gland lateral to the facial nerve. In extracapsular dissection, it is not performed any dissection of the facial nerve 8,10-14 .
There is ample data pertaining to site specific morbidity following parotidectomy (e.g. facial nerve weakness, salivary fistula, and Frey's syndrome); however, the literature on general postoperative surgical morbidity following parotidectomy is lacking 15 . Our investigation aims to provide a reference in parotidectomy surgery including patient demographics, operative variables, and to evaluate the common complications and postoperative outcomes following parotid surgery.

Material & methods:
A retrospective study was done from January 2011 to December 2019 in the Department of ENT & Head Neck Surgery, Enam Medical College & Hospital, Savar. Sixty (60) patients with both benign & malignant parotid disease underwent surgical treatment was selected for this study.
All cases were diagnosed preoperatively by Fine Needle Aspiration Cytology (FNAC) and confirmed by postoperative histopathology report. Patients with preoperative facial nerve palsy were excluded from this study. Investigator himself was remain vigilant on every aspect of the study starting from case selection, follow up, investigating patients, data sheet filling up, maintenance of all records, data checking, data entry, analysis and report writing. He was personally examine each and every case and was constantly guide the proceeding as far as possible. Patients were followed up for six months and postoperative complications were evaluated.       16,17 . In this study temporary paresis resolved within 6months.The rate of facial nerve injury was higher in recurrent cases & those involved the deep lobe of parotid. Malignancy and recurrent tumors were common risk factors of postoperative facial weakness in previous studies [22][23][24] . In our study, the size of the tumor was not a significant risk factor for facial weakness, but the subsite of the tumor was. Previously, one study found that tumors larger than 70 cm 3 correlated with a significant risk for facial weakness 18 . In the case of malignant tumors, it is important to secure a safety margin during surgery. Therefore, there can be a high possibility that the facial nerve is intentionally resected during surgery. The rate of recurrence is very low (0%) in this study.The clinical incidence of Frey's syndrome, after parotidectomy, has been reported in various studies, to be as high as 50% (severe in 15%). Gustatory sweating is detected in almost 100% of cases, evaluated by means of a post-operative iodine-starch test 17 . Salivary fistula and sialocele are usually self-limiting problems and are initially submitted to conservative treatment. Anticholinergic drugs induce a temporary decrease in salivary secretion and are consequently considered useful in fistula management.

Conclusion:
Transient facial palsy is the most common postoperative complication. The best means of reducing iatrogenic facial nerve injury in parotid surgery still remains a clear understanding of the anatomy, good surgical technique with the use of multiple anatomic landmarks & use of modern instruments eg. nerve monitor.

Limitations:
This study is subject to some limitations inherent to the use of a large national database. It is hospital based one centre study that is not representing whole feature of country The most notable of these is the absence of procedure-specific outcomes such as facial nerve paresis or recurrence and the inability to assess complications beyond six months of postoperative period.