[Collateral sprouting at end-to-side neurorrhaphy site demonstrated by nerve fibers micro-tease technique].

OBJECTIVE

To develop a technique that can directly demonstrate collateral sprouting of intact nerve fibers at end-to-side neurorrhaphy site.

METHODS

Five Wistar adult rats were used in this study. The common peroneal nerves at one side were sectioned at the level of knee joint, and their distal ends were sutured to the tibial nerves after removal of a 1 mm-diameter window in the epineurium. Three months after the operation, the nerve segments at neurorrhaphy site and the normal tibial nerves at the contralateral site were harvested. The specimens were fixed in 10% formaldehyde and post-fixed in 1% osmium tetroxide, then macerated in glycerol. Single fiber was teased out in pure glycerol under an operative microscope, then transferred to a slide and observed under light microscope. The nerve segments at neurorrhaphy site and distal peroneal nerves were also harvested for histological evaluation.

RESULTS

At the neurorrhaphy site, small nerve fibers sprouted from a donor nerve fiber near node's of Ranvier. While such phenomena were not found in normal tibial nerve. From the longitudinal section of neurorrhaphy site, bundles of nerve fibers ranged from tibial nerve to peroneal nerve were observed. Lots of regenerative nerve fibers emerged in distal peroneal nerve.

CONCLUSION

The phenomena of collateral sprouting at end-to-side neurorrhaphy site can be demonstrated directly by nerve fiber micro-tease technique.