Surgical repair and nerve grafting are currently the standard treatment for nerve laceration. However, even with that, the functional outcome in patients with proximal nerve cut is often poor. In those cases, the surviving axons in the proximal nerve stump have already reached their capacity limit to sprout and to reinnervate. Therefore, no further reinnervation can occur even with surgery unless regeneration and extension of the proximal stump can somehow be enhanced. Unfortunately, although many attempts, none were shown to be effective in the clinical setting.