Evaluation of Tension at Median and Ulnar Nerve Repairs at the Wrist in a Cadaveric Model.

Median and ulnar nerve lacerations at the wrist are often combined with zone 5 tendon injury. The inability to provide early range of motion leads to increased adhesions. Current therapy protocols recommend the wrist be held in 30° of flexion post operatively to protect the nerve repair. However, if tension and elongation across the nerve repair stay under a critical level in less wrist flexion, postoperative splinting in more extension could allow for better tendon excursion and less adhesions. Six cadaveric specimens were used. After appropriate dissection, the median and ulnar nerves were transected and repaired with a single 10-0 nylon suture. The wrist was ranged from 30° flexion to 45° extension to see if the repair would fail. Next, an epineural repair was accomplished with 9-0 nylon suture. The percent elongation along the nerve repair was measured at set increments from 30° flexion to 45° extension. In all 6 specimens, median and ulnar nerve repairs with a single 10-0 nylon suture did not fail with wrist range of motion from 30° flexion to 45° extension. Mean percent elongation stayed under critical levels in up to 30° of extension. Both median and ulnar nerve repairs stayed under critical levels of tension and elongation in up to 30° of wrist extension. We believe it is possible to be more aggressive with wrist positioning in wrist level median and ulnar nerve repairs.