Treatment Strategy for Oral–Ocular Synkinesis Following Facial Nerve Palsy: A Clinical Classification Based on the Palpebral Fissure Ratio

This is the authors' abstract. We don't add key points for this paper.

Background: Oral-ocular synkinesis is a disabling sequela of facial nerve palsy, characterized by involuntary orbicularis oculi contraction during oral movements. To better guide clinical management, we developed a novel classification system based on the palpebral fissure ratio with oral movement (mPFR). Methods: This retrospective analysis considered 10 cases of oral-ocular synkinesis between April 2022 and March 2024. Patients were categorized into 4 types: type I (mild; mPFR, 90%-100%), type II (moderate; mPFR, 30%-89%), type III (severe; mPFR, 0%-29%), and type IV (fluctuating; unpredictable mPFR irrespective of intervention). Results: Type I and II patients may respond well to botulinum toxin injections and/or mirror biofeedback, which can improve mPFR and reduce subjective discomfort. Type III patients or refractory type II cases may benefit from selective neurectomy or myomectomy. In patients with incomplete facial paralysis within 1 year of onset, nerve reconstruction using cross-facial nerve grafting, masseteric nerve transfer, or cross-link surgery to the hypoglossal can be considered, aiming to restore voluntary facial muscle movement while suppressing synkinetic activity. Notably, type IV patients showed minimal response to botulinum toxin, highlighting the importance of careful classification before intervention. Conclusions: By integrating the objective metric of mPFR with individualized treatment strategies, this classification system may offer a practical framework to enhance both functional and aesthetic outcomes in patients with oral-ocular synkinesis. These findings highlight the importance of accurate evaluation and type-specific therapeutic approaches to improve the quality of life in individuals affected by synkinesis following facial nerve palsy.