[Indications and effects of the SMAS in parotid surgery]

The superficial musculoaponeurotic system (SMAS) is of increasing interest in parotid surgery as a means of reducing the incidence of postoperative gustatory sweating (Frey's syndrome) and improving cosmetic results. Between 1996 and 1998 the SMAS was dissected as a separate plane in 25 patients undergoing parotid surgery for a benign tumour or recurrent infection. After a minimal follow-up of 12 months, all patients were investigated for gustatory sweating and cosmetic appearance. All underwent the starch minor test to document the extent and intensity of postoperative sweating. In a previous publication we found a 43% incidence of Frey's syndrome after parotid surgery without SMAS dissection and starch minor tests were positive in all 23 patients. However, analysis of the current results in patients with SMAS dissection revealed an incidence of Frey's syndrome of only 20%, the results of starch minor tests being positive in 76% with a statistically highly significant (p = 0.006) decrease in extent and intensity. Cosmetic appearance was improved by reduction of the retromandibular depression. Dissection of the SMAS in parotid surgery is indicated in tumours not extending to the parotid capsula. It not only reduces the incidence of Frey's syndrome, but also improves the cosmetic result.