Risk of facial palsy and severe Frey's syndrome after conservative parotidectomy for benign disease: analysis of 610 operations

Conclusions: Advanced age, long operation time and large specimen volume were significant risk factors for transient facial palsy after conservative parotidectomy. Revision operation was the only risk factor for development of a permanent palsy. Risk factors for Frey's syndrome were not found. The incidence of Frey's syndrome was not altered by the use of a sternocleidomastoid muscle flap or other implantation material. Objectives: The results of studies identifying risk factors for facial palsy and Frey's syndrome after parotidectomy are contradictory. This study attempted to identify these risk factors by performing a retrospective review of a large series of patients. Patients and methods: A total of 610 standardized conservative parotidectomies for benign diseases performed between 1989 and 2004 were studied retrospectively. The risk factors for facial palsy and Frey's syndrome were determined by univariate and if possible by multivariate analysis of variables related to patient demographics and operation characteristics. Results: The rates of transient facial palsies, permanent facial palsies and Frey's syndrome were 18%, 4%, and 4%, respectively. Significant univariate and multivariate risk factors for development of a transient facial palsy were age > 70 years, operation time > 260 min, and a specimen volume > 70 cm(3). The only significant risk factor for the development of a permanent palsy was prior surgery. A significant risk factor for the development of Frey's syndrome could not be estimated.