Protocol for randomized controlled trial of brief intraoperative electrical stimulation across cross-face nerve grafts in patients with facial paralysis

Brief Intraoperative Electrical Stimulation (BIES) can enhance axonal regeneration across axotomy sites. Cross-Face Nerve Grafts (CFNG) are typically performed in two stages, with a 6-12-month interval to allow for axonal growth. This provides an opportunity to assess axonal regeneration via biopsy. We describe a protocol to evaluate the effects of a 10-minute BIES on axonal regeneration across CFNG. This is a protocol for a multicenter, double-blind, randomized controlled trial in patients with unilateral facial paralysis undergoing two-stage CFNG. After nerve coaptation, the intervention group will receive 10 minutes of BIES (biphasic current, 2mA amplitude, 100 µsec pulse duration, 16 Hertz) applied proximal to the donor facial to sural nerve coaptation. Controls will undergo standard surgery without stimulation. The primary outcome is the histological count of regenerated myelinated axons from a biopsy obtained during the second stage surgery. Secondary outcomes include patient reported quality of life and objective facial reanimation based on photo analysis. We aim to recruit 20 participants. This protocol evaluates the impact of BIES on histological, patient reported, and objective facial reanimation outcomes in CFNG.