Selective Neurectomy with Regenerative Peripheral Nerve Interface Surgery for Facial Synkinesis

Background: Selective neurectomy (SN) typically leaves cut nerve endings to be either free-floating or buried in facial muscles. Regenerative peripheral nerve interfaces (RPNIs) use autologous skeletal muscle grafts to provide a nonfacial muscle target for reinnervation. Objective: To evaluate the effectiveness of RPNI surgery with SN for improving postoperative facial function through botulinum toxin use and facial movement metrics. Methods: This was a retrospective cohort study comparing patients with synkinesis undergoing SN with and without RPNI surgery. Outcomes included assessing botulinum toxin dosage/frequency and facial movement metrics (margin to reflex distance, brow movement, smile excursion). Statistical tests were applied based on variable distribution. Results: Twenty-four patients were included (12 with RPNI surgery and 12 without; average age, 52.3 and 55.0 years, respectively; p = 0.552). No significant differences were observed in etiology or nerves sacrificed. Patients with RPNI surgery required lower botulinum toxin dosage (72.2 vs. 90.3 units; p = 0.031) and had longer treatment intervals (83.5%, 5.6 months vs. 17.9%, 4.6 months; p = 0.015). No significant differences were observed in facial movement metrics. Conclusion: RPNI surgery with SN may improve facial function as measured by a proxy of reduction in postoperative botulinum toxin dosage and frequency.