P11.37.B RADIOSURGERY-ASSOCIATED NEW-ONSET FACIAL SPASM AFTER THE TREATMENT OF VESTIBULAR SCHWANNOMA IS ASSOCIATED WITH INCIDENCE OF RECURRENCE

Abstract

Abstract BACKGROUND Facial function preservation in the care of vestibular schwannoma (VS) is pre-dominantly measured in motoric function (e.g. House-Brackman (HB)). Facial spasm (FS) has been reported to be a possible side-effect in the radiosurgical treatment of VS. However, the exact incidence of FS is still unclear. MATERIAL AND METHODS This study aims to study the incidence of FS in the treatment of VS. Patient medical records of patients treated by treatment of VS between 2004 and 2020 ere analyzed retrospectively. Patient and tumor characteristics were analyzed (i.e., sex, age, tumor extension and size, intracanalicular extension). RESULTS N=104/1’998 (5%) of all patients treated by SRS presented with new-onset FS postinterventionally. FS was unrelated to tumor size. The incidence of new-onset FS was significantly higher in women (6%) compared to men (4%) (p=0.032). From all patients with FS, N=24/104 (23%) of new onset FS appeared after Re-SRS (second SRS treatment). In primary SRS therapy, facial spasm was associated with a higher recurrence rate of N=20/80 (25%) vs N=252/1"894 (13%) in nonFS patients (p=0.007). N=65/104 (62%) were permanent FS, whereas N=41/104 (39%) recovered spontaneously between 4 and 34 months, postinterventionally. The proportion (76%) of FS patients had tumors with extensive intra-canalicular extension (OHATA A-B) was higher in compared to a nonFS control group (64%) (p=0.015). CONCLUSION FS is a SRS therapy-related side effect with an overall incidence of 5%. Women were more commonly affected by new-onset SRS. Second-line SRS has the highest risk for new-onset FS. FS was associated with a higher incidence of recurrence compared to non-FS VS patients. Patients" consultation should address the relevant side effect.