| Objective:To investigate The effect of fatigue load on the lumbar disc appearance after discectomy by establishing the young pig model of disc fatigue load experiment after operation.Methods:4 samples of pig lumbar spines were selected and divided into two groups randomly:operative group during unilateral vertebral plate disectomy(group A) and control group(group B).Each group was dissected into 8 functional spinal units(FSU) and subjected to fatigue loading under the same parameter(the flexion angle was 9°,the rotation angle was 3°,the peak load was 3500N,the load frequency was 3Hz).Discograpy was taken on two groups before and after fatigue load experiment to measure the dimension of total disc,annuli fibrosi area,nucleus area and contrast agent area respectively.Frozen sections were taken on two groups after fatigue load experiment.Results:Total disc dimension of two group increased after load experiment (P<0.05).Group A showed that annuli fibrosi area increased(P<0.05) and nucleus area did not change after load experiment(P>0.05).Group B showed that annuli fibrosi area decreased(P<0.05) and nucleus area increased after load experiment(P<0.05).Contrast agent area in nucleus area of two groups increased after load experiment(P <0.05) and the proportion of Contrast agent area to nucleus area of group B was greater than that of group A after load experiment(P<0.05).No annuli fibrosi tear was found in two groups either by discography or by frozen section.Conclusions:The lumbar disc of young pig usually still can be able to bear a greater burden after discectomy and the physical structure of the disc may not be damaged seriously.The related function of young patients after discectomy have not declined significantly compared with the preoperative,which may be related to disc structure without significant damage after load experimnet.It provided the biomechanical foundation of animal experiments for explaining the clinical effects on young patients generally better than on elderly patients.
|
PDF Full Text Request