Morphofunctional analysis of sciatic nerve and motor performance of rats after cryotherapy with liquid nitrogen

Abstract

OBJECTIVE: This work evaluated sciatic nerve regeneration after cryotherapy.STUDY DESIGN: Rats underwent surgical access of the sciatic nerve and subsequent cryotherapy, crush lesion, or no manipulation. Walking-track, electroneuromyographic, and histomorphometric analyses were performed at 15, 30, and 70 postoperative days. RESULTS: At 15 days, the crush and cryotherapy groups showed significant morphofunctional impairment. At 30 days, functional loss was significant in the walking-track, but at 70 days, there were no significant differences between the groups. Amplitude was near zero for the crush group at 15 and 30 days and zero for the cryotherapy group. Measurement of latency was not possible in the latter group. Crush and cryotherapy groups showed greater amounts of myelinated fibers (by 30 days), with axonal diameter and width of the myelin sheath being less than in control group. CONCLUSIONS: Sciatic nerve lesion by application of liquid nitrogen is classified as axonotmesis, which is reversible.