Control of Frey's syndrome in patients treated with botulinum toxin type A

Abstract

Aim: To identify the severity of Frey s syndrome and its response to botulinum toxin type A.

Methods: Minor test was performed in all cases to assess the extent of the affected area, using the contralateral side as control. Severity was assessed according to the proposal of Luna-Ortiz et al. Response was evaluated after 3 and 6 months, and was compared with the basal data.

Results: Frey s syndrome was documented in 38 patients, but only 23 cases accepted the botulinum toxin type A treatment. Severity was moderate in 8 (35%) and severe in 15 (65%) cases. Mean applied dose was 1.41 MU/cm2 in 21 patients (91%), whereas one patient was treated with 10 MU for a 0.8 cm2 affected area (12.5 MU/cm2) and another patient with 10 MU for a 0.5 cm2 affected area (20 MU/cm2) due to severity of their symptomatology. Average affected area at the beginning was 14.2 cm2, while after 3 and 6 months of treatment it was 4.1 cm2 and 4.4 cm2 respectively (p<0.001). The two patients that received higher doses of botulinum toxin A had complete response. Complete response was observed in 13 patients (56.5%) at 3 months, but in only nine (39%) this lack of symptomatology persisted at 6 months. In three cases (13%) no response was obtained at 3 months, and the application of an additional dose of botulinum toxin type A produced no response in two of them after 6 months. Comparison of the severity score of the average basal value vs. that obtained at 3 and 6 months revealed a significant difference (p<0.05); however, no statistically significant difference was found when comparing outcome at 3 vs. 6 months. There were no statistically significant differences using the independent samples test when comparing outcome after treatment in relation to gender, type of surgery, or use of postoperative radiation therapy (p>0.05). In conclusion, botulinum toxin A remains as the treatment of choice for Frey s syndrome.