EVIDENCE IN SUPPORT OF COLLATERAL SPROUTING AFTER SENSORY NERVE RESECTION

The extent and time course of sensory recovery has been investigated i n 13 patients who had resection of a cutaneous nerve. Seven patients w ere studied within 8 weeks of denervation; 6 others were studied more than 6 months after denervation, Touch sensation was evaluated using a computer-assisted measuring device that recorded the pressure thresho lds for static and moving touch, and static and moving two-point discr imination within a continual range from 0.1 to 100 gm per square milli meter. Recovery of sensation within the autonomous zone of the resecte d nerve could be documented as early as 3 weeks after denervation. Aft er 6 months, two-point discrimination had recovered in the previously denervated areas. Thresholds for all test modalities were found to be elevated within the sensory distribution of adjacent nerves, which sug gests that these areas have been the donor source for reinnervation of the chronically denervated territory. Anesthetic block of these adjac ent donor nerves resulted in loss of the recovered sensation.