Changes of the F-wave in the acute phase of permanent spinal cord ischaemic injury predict spinal cord function in animal models of rabbits

Objective:to explore the changes of the F-wave in the posterior tibial nerve of rabbits after different levels of lumbar spinal cord ischaemic injury and its correlation with motor function and the extent of lumbar spinal cord pathological damage.Methods:thirty New Zealand rabbits were randomly divided into 6 groups.The control group(n=5)was used to exclude the influence of anaesthesia and surgery on the F-wave.Different levels of lumbar arteries were ligated in the five experimental groups(n=5).The F-wave was recorded to observe the changes in the acute phase of spinal cord ischaemia.The correlation between the changes of the F-wave in the acute reversible phase and the motor function of the spinal cord was analysed.Motor functions were assessed after surgery and 2 d after vascular ligation.The specimens were taken 2 d after ligation for histopathologic observation.Results:the results for the control group indicated that anaesthesia and surgery did not affect the F-wave results.There was no statistically significant difference in the F-wave amplitudes and latency before and after ligation in the 1 and 2 level ligation groups.The F-wave changed immediately after ligation in the 3,4 and 5 ligation groups.The latency of the F-wave gradually extended,the amplitude of the F-wave gradually reduced.The amplitude variations of the F-wave were positively correlated with the motor function 2 d after ligation,there was a statistically significant difference.With the increase in the number of vascular ligation,the degree of destruction of the motor neurons in the anterior horn of the spinal cord in the pathological specimens increased.Conclusion:the F-waves in the posterior tibial nerve of rabbits were found to be sensitive to the lumbar spinal cord ischaemic injury and specific to predict motor function.