Peripheral and Trigeminal Nerve Stimulation Improve Functional Outcomes of Nerve Recovery in a Rodent Forelimb Gap Repair Model

Abstract Background: It is well established that peripheral nerve stimulation (PNS) improves outcomes following nerve injury. By contrast, the trigeminal nerve has not yet been explored as a target of electrical stimulation (ES) for this indication. The hypothesis of this study is that the trigeminal nerve stimulation (TNS) and PNS improve functional outcomes of peripheral nerve injury in a rat forelimb model when compared to rats not receiving ES. Methods: Forty-five male Lewis rats were randomized into 4 groups: (1) sham injury, (2) nerve injury with sham ES, (3) nerve injury with PNS, and (4) nerve injury with TNS. Following repair, rats in the PNS group were stimulated for 1 hour. During rehabilitation, the TNS group received a 500ms train of ES immediately following each successful reach and grasp. Functional motor and sensory metrics were collected both pre-injury and throughout rehabilitation. Results: The sham ES group did not recover their pre-injury baseline functional outcome measurements by the final week of recovery. In contrast, the PNS and TNS groups fully recovered following injury as there was no difference in functional outcomes between the pre-injury baseline and final week of rehabilitation (p > 0.05, all). Conclusions: Trigeminal nerve stimulation and PNS are viable therapies to improve outcomes of nerve injury.