BIOMECHANICAL EFFECTS OF OPERATIVE NERVE MOBILIZATION AND TRANSPOSITION IN A CANINE ULNAR NERVE MODEL

The purpose of this study was to evaluate the effects that operative m obilization and transposition of the ulnar nerve have on both neural e xcursion and mechanical properties. Twelve dogs underwent ulnar nerve transposition and postoperative casting. Four animals were killed at 3 weeks and four animals were killed at 6 weeks. Four animals had their casts removed at 3 weeks, were allowed to ambulate, and were killed a t 6 weeks. Operated and contralateral control nerves were compared. Ne ural excursion was measured near the elbow and 12 cm proximally. The n erves were harvested and their mechanical properties determined. Repea ted measures analysis of variance revealed significant differences in longitudinal excursion between control and experimental groups at both sites. Ultimate strain, ultimate strength, and modulus were significa ntly reduced in the experimental groups. No differences were seen in c ross-sectional area or stiffness between control and experimental grou ps. Analysis revealed no independent effect of the rehabilitation meth od. Results of this study indicate that significant changes in neural excursion, ultimate strain, ultimate strength, and modulus occur follo wing ulnar nerve mobilization and transposition and that these changes persist throughout the early postoperative period.