An In Vivo Wireless Passive Electrical Stimulation Device for Promoting Axon Regeneration and Enhancing Sensory Afferents After Contralateral Seventh Nerve Transfer Surgery

Abstract

CC7 (contralateral cervical seventh nerve transfer) is an effective treatment for spastic hemiplegia caused by brain injury. After stroke, contralateral C7 nerve transfer facilitates the transmission of sensory information from the affected upper limb to the intact cerebral hemisphere. This process promotes cortical reorganization and ultimately enhances motor function recovery in the paralyzed limb. However, there is no effective method to accelerate motor function recovery and enhance sensory input following CC7 surgery. Electrical stimulation has been proposed as a valuable solution for nerve injuries, yet its effectiveness post-CC7 surgery remains unknown. In this study, we firstly investigated the potential of a wireless passive electrical (WPE) stimulation device in vivo as a rehabilitation approach. Subsequently, using the sciatic nerve model, we implanted the WPE electrodes to perform electrical stimulation and then evaluated nerve regeneration and motor function recovery using immunohistochemistry and behavioral analysis. Furthermore, we implanted the device in the transferred C7 nerve of CC7 mice and performed targeted electrical stimulation. We used immunofluorescence, electrophysiological, and behavioral assessments to explore the effects of repeated, targeted electrical stimulation on nerve regeneration, contralateral hemisphere remodeling, and motor function recovery in the paralyzed arm. The WPE stimulation protocol can effectively promote the regeneration of sensorimotor fibers after nerve repair. When applied to CC7 mice, it can accelerate the remodeling of the contralesional hemisphere by enhancing the ipsilateral sensory input and restore the impaired limb function. This stimulation modality can be considered a potential rehabilitation means to accelerate the efficacy of CC7 surgery.