Periocular motor neurotization: a systematic review of techniques and outcomes in orbicularis oculi reinnervation.

Background: Periocular motor neurotization is a surgical approach that can be indicated for the restoration of dynamic eyelid function in patients with facial nerve palsy. The orbicularis oculi muscle, responsible for eyelid closure, can be the target of a variety of re-innervation techniques, such as direct nerve transfers and muscle transpositions. This systematic review aims to map the existing evidence on direct neurotization techniques of the OOM, including nerve grafting, nerve transfers, and contralateral muscle transposition, and to describe their published effectiveness. Methods: A systematic search of PubMed, Embase, and supplemental searching with citation chaining using google scholar to identify studies detailing periocular neurotization techniques. Studies were included if they reported clear outcomes such as restored blinking or eye closure, improved corneal protection, and enhanced eyelid symmetry. Results: Of 857 screened studies, 6 met inclusion criteria, comprising 4 cohort studies, 1 case series, and 1 case report, with 106 patients eligible for detailed extraction. Direct neurotization of the OOM was associated with improvements in eye closure, blink reflex, and electromyographic data. Motor donor nerve selection was noted to affect outcomes significantly, with contralateral facial nerve branches yielding the highest blink improvement. Conclusions: This review highlights the emerging role of direct neurotization techniques in reinnervating the orbicularis oculi muscle for appropriate patients with facial nerve palsy. Future high-quality studies are needed to establish clear indications, long-term efficacy, and comparative advantages of direct OOM neurotization in clinical practice.