Botulinum Neurotoxin for Postoperative Facial Nerve Paralysis: A Technical Note

Excision of a vestibular schwannoma or any lesion in close proximity to the seventh cranial nerve (facial nerve) can compromise the nerve due to traction or, less commonly, neuropraxia. We retrospectively evaluated the effect of botulinum neurotoxin (BoNT) on preventing exposure keratitis in patients with postoperative facial nerve paralysis. We included 18 patients with postoperative lower motor neuron (LMN) facial nerve paralysis. All these patients had received BoNT injections into the upper eyelid in the postoperative period as an alternative to tarsorrhaphy. BoNT was effective in inducing ptosis in 14 patients. Partial ptosis was observed in ten patients, and complete ptosis in four. None of these patients developed exposure keratitis. Botulinum toxin is an effective therapy in preventing exposure keratitis in patients who developed LMN facial palsy postoperatively. It does not have any immediate or late complications.