Nerve regeneration through side-to-side neurorrhaphy sites in a rat model:A new concept in peripheral nerve surgery

Despite great improvement and refinements in nerve repair techniques, there were still problems in repair of peripheral nerve injuries for which proxi mal stumps were not available. In these circumstances for which classic end -to-end neurorrhaphy was impossible, new treatment modalities, benefiting b y an adjacent healthy nerve, have been under investigation to overcome this problem. Therefore, end-to-side nerve repair with its modifications came t o vie iv and axonal passages through this site were shown. Moreover, the re sults were unsatisfactory or necessitating sacrifice of another healthy ner ve. Three groups, containing 10 rats each, were included in the study. First wa s the control group, vith end-to-end repair of the peroneal nerve. Second w as the end-to-side repair group, in which the distal stump of the peroneal nerve trunk was anastomosed to the lateral side of the tibial nerve. The th ird was the side-to-side repair group. In this technique, 1-mm diameter epi neural windows, both from peroneal and tibial nerve trunks facing each othe r, were removed and side-to-side neurorrhaphy was performed. lifter 3 weeks , as the second step, the peroneal nerve was sectioned proximally. At 2, 4, 8, 12, 20, and 28 weeks, functional assessment of nerve regenerati on was performed by using walking track analysis. The number of myelinated fibers and fiber diameters were measured and an electron microscopic evalua tion was carried out. Statistically, body in morphometric and gait analysis , the differences in values between the groups were significant in favor of the control group, followed by the side-to-side group. The study showed that axonal passage was possible with side-to-side techniq ue and the functional results were satisfactory and superior to the end-to- side technique. Continuous supply of neurotrophic factors from their target cells was the probable cause of superior functional return in side-to-side repair, because both joining nen es were intact and healthy during the ana stomosis procedure and after 3 weeks. It was concluded that this technique could be indicated in salvage of nerves in cases for which any intermediate segments would be removed, as in tumor ablation surgery, harvesting of ner ve grafts, or both.