End-to-side nerve repair: attachment of a distal, compared with a proximal and distal, nerve segment

Regeneration occurs if a distal nerve segment is attached end-to-side to an intact donor nerve after the nerve has been injured. We investigated if attachment of a proximal nerve segment as well, as an extra source of axons, had any advantage over the single attachment of a distal nerve segment to the same donor nerve. In rats, a single distal radial nerve, or both the proximal and distal radial nerve segments, were attached end-to-side to the musculocutaneous nerve, and effects were examined up to eight months after the repair. Cell profiles were double-labelled, indicating recruitment of axons by collateral sprouting, but there were few such cells. There was a shift in the distribution of retrograde labelled neuronal cell profiles in spinal cord and in DRGs between the two types of repair. Both procedures resulted in axonal outgrowth and some functional recovery, but there was no improvement if a proximal nerve segment was also used as a source for axons.