Partial nerve injuries in the upper extremity.

The level of injury of a peripheral nerve is a critical factor that has a great impact on the result of the repair. At the level of the wrist, the median and ulnar nerves have pure motor and sensory fascicular groups. Proximal to the wrist, the motor fascicular groups combine with sensory fascicles and become mixed nerves. Mapping the fascicular orientation with electrical stimulation is indicated for injuries located from the wrist to the distal third of the forearm. Successful application of this technique depends on the level of injury, anesthetic technique, and careful patient selection. Children and patients with other serious coexisting injuries are not candidates for this technique. The depth of anesthesia must provide adequate analgesia while allowing the patient to communicate and cooperate with the surgeon during the procedure. There are few reports in the literature about repair of partially injured nerves in the upper extremities and the comparison of functional outcomes with or without the use of nerve grafts is not easy. Even under ideal operative conditions and with ideal indications, the outcomes are not always satisfactory. Hurst et al reported very good results using end-to-end repair of fascicular groups in their series. Using the rating system of the British Medical Research Council, they reported motor values of 4.0 (normal 5.0), and sensory values of 3.8 (normal 4.0). Kato et al reported very good results in their series of 51 cases with group fascicular end-to-end suture using orientation with electrical stimulation. In this series, there were five patients with partial nerve laceration and end-to-end coaptation of the fascicular groups provided very satisfactory outcome. End-to-end repair of the fascicular groups seems to provide better results than repair of the nerve using nerve grafts. It is desired, however, that the nerve gap be less than 2 cm for the application of end-to-end repair of the nerve.