Functional degradation of the rabbit sciatic nerve during noncompressive segmental ischemia

The purpose of this study was to evaluate functional degradation in a nerve with a local ischemic segment created without a direct compression effect. Ischemia of one segment of a rabbit sciatic nerve was induced by stripping the nerve's extrinsic blood supply along 15 cm. Blood flow of both in situ and ischemic nerves was quantitatively measured with radioactive microspheres in six serial segments in seven animals. The flow in one middle segment of the stripped nerve was significantly reduced to 0.1 ml/min per 100 g (p = 0.006). In another eight animals, both in situ and stripped nerves were metabolically challenged with repetitive stimuli (200 Hz). Conduction velocity and peak amplitude were measured before stimuli, after 30 and 60 minutes of stimuli, and after a 30-minute recovery period. Conduction velocity was reduced in both nonischemic and stripped nerves during prolonged repetitive stimulation. Peak amplitude was reduced slightly in the nonischemic group and markedly in the stripped group. Normal or higher values were seen again in both groups during the recovery period. It was demonstrated, therefore, that conduction properties of the nerve, especially amplitude, can be affected by localized ischemia in one segment.