Functional aspects of reinnervation of free skin grafts.

The reinnervation of full-thickness skin grafts has been studied with single mechanosensory unit recordings. Shortly after transplantation of the skin, most of the incoming fibers conduct impulses at slow velocities, which correspond to the unmyelinated group of sensory fibers. The older skin grafts demonstrated an increasing amount of myelinization as shown by the shorter latencies and faster conduction velocities. However, the critical balance between myelinated and unmyelinated fibers that characterizes normal cutaneous innervation was still disrupted in the grafted groups at 15 months. Whether this imbalance persists indefinitely is uncertain. The introduction of electrophysiological techniques into the study of peripheral nerve injuries, in experimental animals and in man, has given us some insight into the unexplored nature of this field of experimental and clinical investigation. The future promises to be exciting.