Conduction study of digital nerve function recovery following toe-to-digit transplantation and a comparison with digit-to-digit replantation.

Recovery of digital nerve function following toe-to-digit transplantation was studied by nerve conduction in 16 patients, and a comparison was made with digit-to-digit replantation in 7 patients. For toe transplantation and digit replantation, the mean interval between injury and surgery was 7 months and 8 h, respectively, while the mean interval between surgery and study was 39 months and 25 months, respectively. Sensory nerve action potentials (NAPs) from digital nerve stimulation were recorded at the wrist and the elbow, whereas mixed NAPs from median nerve stimulation at the wrist were recorded at the elbow. Sensory NAPs from stimulation of the transplanted toe were detectable in 14 patients and showed reduced amplitude, prolonged latency, and slowed conduction velocity. There was retrograde amplitude reduction in the median nerve and in the proximal segment of the digital nerve. Sensory NAPs from the replanted digit were not different from those of the normal digit, nor was a retrograde effect observed. The present data indicate that digital nerve function recovery was incomplete in toe transplantation and nearly complete in digit replantation. The reasons for the differences in recovery following two types of nerve repair are discussed.