Repair of severed peripheral nerve: a superior anatomic and functional recovery with a new "reconnection" technique.

The objective of this study was to use a quantitative functional and anatomic model to compare surgical repair of the rat sciatic nerve according to two techniques; standard epineurial repair and the recently reported "nerve reconnection technique" ("freeze-trim technique"). Functional recovery was evaluated using a functional index based on the measurements of the rats' footprints. Neuroanatomic experiments were conducted on the same animals to correlate functional recovery with regeneration of known motoneuron populations. The results of surgical repairs were also compared to those obtained from untreated sciatic nerve crush injuries. Functional recovery after epineurial repairs typically averaged 18%, whereas the mean recovery from the "nerve reconnection technique" was 71%. Crush injuries recovered to normal and reached a plateau much earlier than the surgical repairs. Retrograde horseradish peroxidase (HRP) labeling of motoneurons of the common peroneal nerve, a branch of the sciatic, revealed that there was a complex relationship between functional recovery and the number and distribution of motoneurons that regenerated axons distal to the repair site. The "nerve reconnection technique" greatly reduced the probability of axonal misdirection into the wrong distal branches at the repair site and brought an improvement of 300% to 400% in functional recovery over that found with epineurial repair. This technique of nerve repair may prove to be a valuable tool in reconstructive surgery.