Topographical, anatomical and neurosurgical aspects of "end-to-side" nerve repair

The article presents the results of a comprehensive anatomical and experimental study of individual variability in the structure and topography of motor branches of peripheral nerves in relation to the justification of methods for selective reinnervation of tissues by the "end-to-side" neurorrhaphy. It was found that relatively longer branches of peripheral nerves with a small number of connecting inter-arm collaterals characteristic of narrow and long limbs create conditions for less traumatic mobilization of motor branches. In cases with relatively wide and short extremities mobilization of peripheral nerves is complicated by the presence of a large number of collateral branches and intra-trunk connections, which are often damaged when separate bundles that make up the mobilized branches of the donor or recipient nerve are isolated from the main nerve trunk. It has been shown that potential recipient nerves should be motor branches of peripheral nerves, the preservation of which is of fundamental importance for the function of the corresponding segment of the limb. To create conditions conducive to selective reinnervation of functionally significant muscle groups of the upper limb, we have developed, justified from anatomical positions, and tested in an experiment on anatomical material methods for connecting the distal motor branches of peripheral nerves by the "end-to-side" neurorrhaphy. The main idea of accelerated recovery of the thumb opposition in injuries of the median nerve is to reinnervate the muscles of the elevation of the I finger due to nerve fibers that are part of the deep branch of the ulnar nerve. For this purpose, surgical techniques have been developed for connecting the recurrent motor branch of the damaged median nerve mobilized at the level of the wrist with the edges of a surgically formed perineurium defect on the lateral surface of the bundles that make up the deep branch of the ulnar nerve. In another clinical situation, in patients with radial nerve injuries, for the muscle reinnervation, а method is proposed for neurotisation of the deep motor branch of the radial nerve by the end-to-side suture to the lateral surface of the median nerve. We assume that performing the "end-to-side" nerve suture at the level of the base of the hand in the cases of proximal damage to the median nerve will reduce the time of reinnervation of the muscles of the thumb elevation by 400–450 days. Transposition of the deep branch of the damaged at the proximal level radial nerve with "end-to-side" neurorrhaphy to the median nerve — by 250–300 days (based on the total length of the shoulder and forearm, which is about 50 cm and the rate of regeneration of nerve fibers 1 mm per day). Accordingly, with higher injuries (brachial plexus), the gain in the time of reinnervation of the distal segments will be even greater. In our opinion, the results can be used as a basis for further clinical research on the development of methods for selective tissue reinnervation in cases with isolated injuries of the peripheral nerves.