The author reports his experimental work on upper extremity peripheral nerve transplantation into the spinal cord using an animal model. The radial nerve in 15 Sprague Dawley rats was cut at its origin from the brachial plexus and connected by means of a nerve graft to the corticospinal tract of the spinal cord at the T3-T4 level. In 5 of 8 surviving rats, the triceps and extensor muscles of the forearm were able to extend the elbow and the wrist and demonstrated almost normal responses on EMG after 4 months. Three surviving rats exhibited lower extremity motor and sensory impairment.
The author emphasized the primary drawback associated with nerve implantation into the spinal cord for reinnervation of the upper extremity: interference with lower limb function. However, this procedure might show promise in the future for very specific nerve injury patterns with existing lower extremity impairment (e.g., complete avulsion of all cervical nerves of the brachial plexus in association with paraplegia).