Control of Frey's syndrome in patients treated with botulinum toxin type A.
To identify the severity of Frey s syndrome and its response to botulinum toxin type A. 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. 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.