Early and continued manual stimulation is required for long-term recovery after facial nerve injury.

ABSTRACT

INTRODUCTION: We previously have shown that manual stimulation (MS) of vibrissal muscles for 2 months after facial nerve injury in rats improves whisking and reduces motor end plate polyinnervation. Here, we seek to determine whether discontinuing or delaying MS after facial-facial anastomosis (FFA) leads to similar results. METHODS: Rats were subjected to FFA and received MS for (1) 4 months (early and continued), (2) the first but not the last 2 months (discontinued), or (3) the last 2 months (delayed). Intact animals and those not receiving MS (no MS) were also examined. RESULTS: Early and continued MS restored whisking amplitude to 43°, a value significantly higher compared with the discontinued, delayed, and no MS groups (32°, 24°, and 10°, respectively). Motor end plate polyinnervation occurred in all experimental groups but was significantly higher in the delayed group. DISCUSSION: Early and continued MS results in better recovery than when it is either discontinued or delayed. Muscle Nerve 57 100-106, 2018.