[Post-parotidectomy Frey's syndrome. Treatment with botulinum toxin type A]

The Frey's syndrome, manifest after parotid trauma, is characterized by head and neck hyperemia and abundant sweating of the hyperemic skin in response to gustatory stimuli. The use of the botulin toxin to treat the symptoms in patients with Frey's syndrome has been described in numerous studies. For some time up until now our Center has achieved excellent results using the group A botulin toxin to overcome the hypertonus of the cricopharyngeal muscle in patients who had undergone laryngectomy and were rehabilitated with voice button. We have sought to extend the use of this toxin to Frey's syndrome, a relatively frequent complication of parotidectomy. A total of 86 patients participated in the study: 41 males (47.6%) and 45 females (52.4%) ranging in age from 25 to 77 years (average age 51 years). Of these patients 7 (8.1%) had undergone post-operative radiotherapy. Of the 86 patients studied, 18 referred significant symptoms in terms of abundance and frequency. The syndrome was considered severe if the symptoms were present at each meal and if the patient indicated a significant worsening of his quality of life. Intermittent episodes were indicated by 22 patients. The remaining 46 (43.5%) did not complain of any symptoms. The exact extension of the cervicofacial gustatory sweating was evaluated using the Minor test and the involved region was divided into 1 square centimeters sections. The amount of skin surface involved ranged from 10 to 80 square centimeters. The type A neurotoxin was frozen and was reconstituted with a sterile saline solution at a final concentration of 2.5 UI/0.1 ml. The intracutaneous infiltration was performed without anesthesia, infiltrating 0.1 ml of solution, containing 2.5 UI of toxin into the center of each 1 square centimeters section. Statistical analysis was performed to evaluate the potential relationship between how long the treatment was effective, incidence of recurrence, seriousness of the crises and the following variables: age, sex, histology, cutaneous surface involved, injected dose of botulin toxin and post-operative radiotherapy. In the group of 18 patients with severe symptoms (20.9%) the benefit was immediate in all cases although the recurrence rate was 50%. The Frey's syndrome symptoms disappeared within 7 days of infiltration. In the group of 22 patients with less severe involvement (25.5%), the treatment gave positive, definitive results in 16 patients (72.7%). Those patients whose symptoms persisted were treated a second time with an infiltration of 2.5 UI per square centimeters. We feel that the use of the type A botulin toxin is the most appropriate treatment for the Frey's syndrome. In fact, such treatment offers the following advantages: it is effective within 7 days, has limited side effects, can be applied on an outpatient basis, is inexpensive and is positively considered by the patients.