Hemihypoglossal-Facial Nerve Anastomosis for Facial Nerve Reanimation: Factors that may Influence the Outcome

The purpose of this study was to identify the factors that may influence the results of hemihypoglossal-facial nerve anastomosis (HHFA). The first 28 consecutive patients who underwent HHFA were analyzed. The facial palsy was related to surgically treated vestibular schwannoma (24), facial nerve schwannoma (1), petroclival meningioma (1), brain stem cavernoma (1) and in one case to purely radiosurgically treated vestibular schwannoma (1). The group included 4 patients with Neurofibromatosis type 2 and also four patients after failed radiosurgery. Duration of facial palsy before the procedure ranged from 1 to 21 months (mean 6.5 months) and was longer than 1 year in 6 patients. The procedure was performed in own modification which is a compilation of the technique described by Darrouzet with the longitudinal splitting technique. The clinical follow-up period was at least 1 year. In 26 out of 28 (93%) patients satisfactory outcome (III° House–Brackmann scale) of CN VII function was achieved. In two remaining patients (both with Neurofibromatosis type 2) facial function improved from paresis to IV° according to House – Brackmann Scale. Patient age, sex, initially treated pathology, previous radiosurgical treatment and time from CNVII injury to anastomosis had no influence on final results. HHFA is an effective modality for treatment of facial palsy with acceptable tongue denervation. Suboptimal results were observed only in NF2 group what might be related to difficulties in rehabilitation process due to common hearing problems or due to other cranial nerve deficits.