What is the difference of the incidence in clinical Frey syndrome in studies comparing classical parotidectomy with parotidectomy with superficial musculoaponeurotic system (SMAS) flap elevation and suturing?
Background: Although treatment of established Frey syndrome with botulinum toxin is effective and well accepted, prevention seems a better alternative. Prevention techniques have all involved some form of barrier between the parotidectomy bed and the skin, but there is a lack of conclusive evidence for the role of superficial musculoaponeurotic system SMAS flaps.
Explore this issue:July 2016
Study design: Meta-analysis of 11 controlled studies comprising 550 patients with and without SMAS flap.
Setting: PubMed and Embase databases.
Synopsis: A decrease in clinical Frey syndrome incidence was observed in nine studies and two found an increased incidence. Differences were statistically significant in three studies, not significant in five; three publications did not perform any statistical evaluation. The majority of parotidectomies performed were superficial, either because of the inclusion criteria of the studies or because of the clinical decision in most patients. Superficial musculoaponeurotic system flap coverage resulted in significantly less clinical Frey syndrome than simple skin elevation. However, the only prospective randomized study did not find a statistical difference in clinical Frey syndrome with SMAS elevation. The main limitations included the quality of the publications included, with few prospective studies and only one randomized study; potential variation in the exact definition of SMAS flap elevation and redraping among surgeons and with each clinical situation; a lack of clear consensus on an increased incidence of Frey syndrome with larger extents of parotidectomy; and the lack of a standardized questionnaire evaluation of subjective Frey syndrome and the non-blinded evaluation in most studies.
Bottom line: SMAS flap and suturing is associated with a decreased incidence of Frey syndrome, but variability among studies is responsible for a very high heterogeneity, and the single randomized of the subject was not conclusive.
Citation: Dulguerov N, Makni A, Dulguerov P. The superficial musculoaponeurotic system flap in the prevention of Frey syndrome: a meta-analysis. Laryngoscope. 2016;126:1581-1584.