Conclusions: Data about the recovery course of facial function after intratemporal facial nerve reconstruction using interposition nerve graft would provide useful information for clinicians to understand the regenerative process of the facial nerve after this type of surgery. It would also enable them to obtain informed consent from the patients by preoperatively explaining the predicted outcome of the postoperative facial paralysis.
Objective: The purpose of this study was to describe the recovery course of facial movement and electrophysiological findings after intratemporal facial nerve reconstruction using interposition graft.
Patients and methods: Five patients who underwent reconstruction of the facial nerve using interposition nerve graft immediately after facial nerve excision during surgery for temporal bone lesions were included in this study. Each patient was evaluated for facial movement (Yanagihara score), blink reflex (BR), and electroneurography (ENoG) preoperatively and postoperatively.
Results: Improvement in facial movement began 8-10 months postoperatively. The score then gradually increased, and reached a plateau level by 2 years following surgery. The final score in four of the five patients ranged from 20 to 24 points, while the facial score of one patient only reached 12 points even at 3 years after surgery. All patients demonstrated moderate to severe synkinesis. The reappearance of R1 in BR occurred 7-10 months postoperatively, almost simultaneously with the beginning of recovery of facial movement. The latency of R1 on the operated side became shortened with increasing postoperative time, although it remained considerably longer than that on the unoperated side, even after 2 postoperative years. The onset of recovery of ENoG value (10-12 months postoperatively) was always delayed compared with the actual facial movement recovery and never returned to the level in the unoperated side.