Reducing the risk of Frey’s syndrome after parotidectomy – which methods are best?
Reviewed by Diana Bhasker

Gustatory sweating or Frey’s syndrome is a well-recognised complication of parotid surgery. The reported incidence is highly variable, from 4% to 96%, with around 30% of patients reporting symptoms. A number of intraoperative techniques can be used to reduce the incidence of Frey’s syndrome and this systematic review aimed to identify the most effective technique. Five existing methods were identified, namely: use of an acellular dermal matrix (e.g., Alloderm), temporoparietal fascia, superficial musculoaponeurotic system (SMAS) transfer, free fat graft transfer or sternocleidomastoid muscle (SCM) transfer. These were compared to no interposition barrier following extracapsular dissection, partial or total parotidectomy. The authors employed a network meta-analysis (NMA) technique to compare data from 34 studies involving 2987 patients. This novel statistical method enables integration of data from various clinical studies comparing the aforementioned techniques. Currently published analyses only provide head-to-head comparison of two interventions (e.g., SCM transfer vs. no barrier). Studies included analysed the presence of objective (confirmed by iodine starch tests) or subjective (indicated by patient questionnaires) Frey’s syndrome following parotid surgery for benign or malignant conditions. Overall, the results of the NMA suggest that an acellular dermal matrix is the most effective at preventing objective Frey’s syndrome; temporoparietal fascia transfer was the most effective at preventing subjective Frey’s syndrome. This is largely in agreement with other published meta-analyses on the topic. The authors note that most studies included do not report time-to-event data to show at what point Frey’s syndrome occurred. Therefore, it is unclear whether interposition grafts/flaps prevent or merely delay the onset of Frey’s syndrome. Interestingly, meta-regression analyses did not show any statistically significant increase in Frey’s syndrome with the type of parotidectomy, adjuvant radiotherapy or disease pathology. The findings in this study are clinically significant when considering optimal patient outcomes following parotid surgery. 

What is the best method for prevention of postparotidectomy Frey syndrome? Network meta-analysis.
Mashrah M, Aldhohrah T, Abdelrehem A, et al.
HEAD NECK
2021;43(4):1345-58.