The acute effect of peripheral nerve transection on digital thermoregulatory function.

Purpose;This study tests the hypothesis that major peripheral nerves serve as important routes for adrenergic neural fibers therefore peripheral nerve injury affects cutaneous perfusion within the nerve's sensory innervation territory. The specific aim of the study was to determine whether an, acute isolated peripheral, nerve injury would result in alteration of blood flow to a specific digit pain and/or cold sensitivity. Methods: The influence of peripheral nerves on their dominant area of autonomic vasomotor function was evaluated in 9 patients who had primary neurorrhaphy after a single complete median or ulnar nerve transection. At a mean follow-up of 47 days the response of digital perfusion to a cold stress was examined in these patients by using isolated cold stress testing and laser Doppler fluxmetry. Patients also completed subjective questionnaires to evaluate their symptoms. Results: The affected hands showed a decreased cutaneous perfusion when compared with the atelral hands during all 3 phases of the cold stress test. In addition cutaneous perfusion patterns evaluated by laser Doppler perfusion imaging showed markedly decreased cutaneous perfusion patterns in the digits within the innervation territory of the injured nerve. There was no notable difference in digital baseline temperatures and temperature changes after an isolated cold stress test between the most affected digits of the injured hands and corresponding digits of the unaffected, contralateral hands. All 9 patients reported mild to severe digital numbness, 8 reported mild to, severe pain, and 4 reported mild to moderate cold sensitivity of the upper extremity. Conclusions: This study documents that cutaneous perfusion and thermoregulatory function is altered after isolated peripheral nerve injury. (J Hand Surg 2003;28A:481-488. Copyright (C) 2003 by the American Society for Surgery of the Hand.)