Contralateral Facial Botulinum Toxin Injection in Cases with Acute Facial Paralysis May Improve the Functional Recovery: Where We Stand and the Future Direction.

Facial nerve (FN) impacts the function of the facial musculature by creating muscle tone at rest as well as the muscles' voluntary and involuntary contractions. Temporary or permanent loss of FN function could be due to different etiologic factors. Acute facial paralysis (FP) could be significantly stressful for the patient and the family and apart from supportive measures management options are quite restricted. While botulinum toxin (BTX) injection in the FP setting has been used mostly to address the compensatory hyperkinesia in the non-paralyzed side of the face, there are evidence to suggest contralateral injection of the non-paralyzed face with BTX may improve/enhance the recovery time of the FP in cases where the FP has a reversible cause. While further studies are underway, using the current evidence as discussed could potentially justify the current usage of contralateral BTX injection and biofeedback exercises in the setting of the temporary FP specialty due to lack of effective alternative management options.