[The incidence of Frey syndrome following parotidectomy: results of a survey and follow-up].

BACKGROUND

Frey's syndrome (FS) is defined as facial sweating due to gustatory stimuli following surgery or trauma of the parotid gland. Concomitant symptoms may occur in the area of the auriculotemporal nerve: swelling, facial flushing, and paresthesia. A misguided re-innervation of perspiratory glands by secretory parasympathetic fibres is likely responsible in the pathogenesis. The reported incidence in the literature varies considerably from 1.7% to 97.6%. The present study aims to clarify the incidence of FS.

PATIENTS AND METHODS

A questionnaire was sent to 221 consecutive patients who underwent parotidectomy between 07/2005 and 07/2008. No selection for type of parotidectomy or histological result was made. Patients were invited to undergo a follow-up examination including Minor's iodine starch test.

RESULTS

A total of 135 of 221 (61%) questionnaires were available for evaluation. In all, 82 patients took part in the follow-up, with a follow-up period of 2.8 years (15-51 months). According to the questionnaire, 54% of patients claimed to be free of symptoms. Sweating following gustatory stimuli was reported by 23% of patients. Of the 82 Minor's tests performed, 62.2% were positive. All patients with subjective presence of FS had a positive Minor's test. In 27%, Minor's test was positive although patients did not suffer from facial sweating subjectively ("subclinical FS"). In all, 39% had no subjective complaints and Minor's test was also negative. Cases with a positive Minor's test showed no statistically significant relation to the patients' age, gender or to the histological diagnosis or type of parotidectomy.

CONCLUSION

The clinical incidence of FS in our study is 23%, although a positive Minor's iodine starch test was observed in 62% of cases. Therefore, it seems justifiable to differentiate between a symptomatic or clinical FS and a merely asymptomatic or subclinical FS. No correlation was observed between epidemiological factors and the occurrence of FS.