PURPOSE:This study evaluates the outcome of superficial musculoaponeurotic system(SMAS) and allograft dermal matrix(ADM) in preventing facial deformity and Frey’s syndrome following parotidectomy.METHODS:Forty-six patients with benign parotid tumors were randomly assigned to 4 groups.The control group consisted of 12 patients who underwent a total parotidectomy;The AMD group consisted of 10 patients who underwent a total parotidectomy and underwent intraoperative placement of ADM within the parotid bed;SMAS group consisted of 11patients who underwent a total parotidectomy and SMAS folded flaps to repair parotid bed;and SMAS plus AMD group consisted of 13 patients who underwent a total parotidectomy and intraoperative placement of ADM to repair parotid bed with SMAS folded flaps.All 46 patients were evaluated via a short questionnaire regarding perception of a facial contour deformity,Frey’s syndrome,modified Minor’s starch-Iodine test(MSIT) ,and clinical examination.RESULTS:Twelve months of follow-up was conducted after the treatment,the rates of satisfaction with the post-operative facial contour were 33.3%(4/12) ,40.0%(4/10) ,91.9%(10/11) and 100%(13/13) respectively in the control group,AMD group,SMAS group and SMAS plus AMD group,and the difference between the SMAS plus AMD group and the former two groups was statistically significant(P< 0.05) .The incidences of objective Frey’s syndrome by MSIT were 50.0 %(6/12) ,20.0%(2/10) ,27.3%(3/11) and 7.7%(1/13) respectively,and the difference between the SMAS plus AMD group and the control groups was statistically significant(P<0.05) .CONCLUSION:The SMAS folded flap is clinically simple to perform,which can prevent depressed facial deformity.Combination of SMAS folded flap and ADM can reduce the incidence of Frey’s syndrome in patients undergoing parotidectomy. PURPOSE: This study evaluates the outcome of superficial musculoaponeurotic system (SMAS) and allograft dermal matrix (ADM) in preventing facial deformity and Frey’s syndrome following parotidectomy. METHODS: Forty-six patients with benign parotid tumors were randomly assigned to 4 groups. The control group consisted of 12 patients who underwent a total parotidectomy; underwent intraoperative placement of ADM within the parotid bed; SMAS group consisted of 11patients who underwent a total parotidectomy and SMAS folded flaps to repair parotid bed; and SMAS plus AMD group consisted of 13 patients who underwent a total parotidectomy and intraoperative placement of ADM to repair parotid bed with SMAS formed flaps. All 46 patients were evaluated via a short questionnaire perception perception of a facial contour deformity, Frey’s syndrome modified Minor’s starch-Iodine test (MSIT), and clinical examination .RESULTS: Twelve mont hs of follow-up was conducted after the treatment, the rates of satisfaction with the post-operative facial contour were 33.3% (4/12), 40.0% (4/10), 91.9% (10/11) and 100% ( 13/13) respectively in the control group, AMD group, SMAS group and SMAS plus AMD group, and the difference between the SMAS plus AMD group and the former two groups was significantly (P <0.05). The incidences of objective Frey’s syndrome by MSIT were 50.0% (6/12), 20.0% (2/10), 27.3% (3/11) and 7.7% (1/13) respectively, and the difference between the SMAS plus AMD group and the control groups was Significant (P <0.05). CONCLUSION: The SMAS folded flap is clinically simple to perform, which can prevent depressed facial deformity. Combining of SMAS folded flap and ADM can reduce the incidence of Frey’s syndrome in patients undergoing parotidectomy.