Botulinum toxin injection effective for post-peripheral facial nerve palsy synkinesis

Facial synkinesis is an involuntary activation of muscles innervated by the zygomatic or mandibular branch of the facial nerve in conjunction with voluntary activation of the other branch. It appears frequently after recovery from peripheral facial nerve paralysis. We report 10 patients with facial synkinesis following Bell's palsy with a mean duration of synkinesis of 7 +/- 4 years before treatment with periorbital injections of Botulinum toxin type A. 9 had marked subjective and objective improvement starting a few days after injection and lasting 4-9 months. The results suggest a useful treatment option for post-Bell's palsy facial synkinesis with Botulinum toxin type A.