Microsurgical management of old injuries of the peripheral nerve and brachial plexus.

A prospective study was carried out in patients suffering from old peripheral nerve and brachial plexus injuries to attempt to validate that functional improvement was possible after microsurgical management. Fifty patients underwent operative procedures, of whom 35 were peripheral-nerve injury cases, from 1.2 to 50 years after injury, and 15 were brachial-plexus injury cases, from 1.2 to 12 years after injury. The patients were treated by external and interfascicular neurolysis and/or autogenous nerve grafts. In cases of preganglionic nerve injury, neurotization from C3, C4 roots was done for reinnervation of trunks or cords. During external and interfascicular neurolysis in 19 of the 35 peripheral-nerve injuries, significant improvement was found in amplitude (p = 0.0001) and latency (p = 0.01) of compound muscle action potentials (CMAPs) at the end of the surgery, compared to the onset of surgery. Twenty (57 percent) of the 35 showed functional motor improvement up to M4-or M4. Electrophysiologic analysis of amplitude of CMAPs 1 year after surgery showed statistically significant improvement (p = 0.0003). Five (33 percent) of the 15 patients with upper brachial-plexus injuries showed functional motor improvement up to M4-(active movements against gravity and slight resistance) or M4 (active movements against gravity and moderate resistance) after surgery and of these, 11 also had lower brachial-plexus injuries, with four (36 percent) showing antigravity function M3 (active movement against gravity). Statistical analysis of recruitment 1 year after surgery demonstrated the appearance of or significant voluntary muscle activity in 45 percent of the muscles. Intraoperative electrophysiologic findings after external and interfascicular neurolysis confirmed that the viability of nerve tissue is of longer duration than previously considered. This study suggests that the use of microsurgical techniques results in the functional improvement of patients suffering from old injuries of the peripheral nerve and brachial plexus.