纤维环切口方式对椎间盘生物力学强度影响的动物实验研究

EXPERIMENTAL STUDY ON EFFECT OF THREE DIFFERENT OPERATIVE WAYS OF ANNULUS FIBROSUS INCISION ON INTERVERTEBRAL DISC BIOMECHANICAL STRENGTH

目的探讨不同切口方式处理椎间盘纤维环对髓核摘除术后山羊椎间盘生物力学强度的影响。方法取30只成年健康山羊,雌雄各半,随机分为A、B、C 3组(n=10)。3组行L_(3、4)及L_(4、5)椎间盘髓核摘除术中,切开纤维环时,分别采用工作套筒刺入(A组)、圆形切口切开(B组)、方形切口切开(C组)。记录并比较3组山羊体质量、雌雄比例、年龄、术中出血量及切口愈合时间;术后观察各组山羊存活及切口愈合情况。术后24周时处死山羊,MRI检查髓核信号强度;游标卡尺测量L_(3、4)及L_(4、5)椎间盘高度,取均值,并计算手术前后高度丢失程度;生物力学测定L_(3、4)诱发椎间盘突出的压力值及椎间盘承受的最大压力值;大体、组织学染色观察L_(4、5)椎间盘纤维环的修复效果。结果 3组山羊体质量、雌雄比例、年龄、术中出血量、切口愈合时间比较差异均无统计学意义(P>0.05),具有可比性。3组山羊均存活至实验完成。MRI检查3组椎间盘均可见退变现象,信号均降低;根据改良Thompson分级法,A组椎间盘退变程度高于B、C组(P<0.05),B、C组间比较差异无统计学意义(P>0.05)。3组术前椎间隙高度比较差异无统计学意义(P>0.05);但术后24周A组椎间隙高度高于B、C组,其丢失程度低于B、C组差异均有统计学意义(P<0.05)。A组诱发椎间盘突出的压力值及椎间盘承受的最大压力值均显著大于B、C组(P<0.05),B、C组间差异无统计学意义(P>0.05)。HE及Masson染色示:A组纤维环连续性良好层次较清淅;B、C组切开处可见纤维环连续性破坏,瘢痕组织填充明显。结论椎间盘髓核摘除术中,采用工作套筒切开纤维环对纤维环结构破坏小,对维持椎间盘生物力学强度及术后纤维环修复起到积极作用。

Objective To discuss the effect of three different ways of annulus fibrosus incision on the biomechanical strength of intervertebral disc.Methods A total of 30 goats underwent intervertebral disc nucleus pulposus extraction at L_（3,4） and L_（4,5） by the working channel in group A（n=10）,by circular incision in group B（n=10）,and by square incision in group C（n=10）.The body weight,male and female ratio,age,intraoperative blood loss,and wound healing time were recorded and compared among 3 groups.The survival rate and wound healing situation were observed after operation.At 24 weeks after operation,the goats were sacrificed,MRI images were taken to observe the signal intensity of nucleus pulposus.The disc height of L_（3,4） and L_（4,5） was measured to calculate the loss of disc height;biomechanical test was used to assess the strength of the disc and anulus.Histological staining was also conducted to observe the repair effect at L_（4,5）.Results There was no significant difference in body weight,male to female ratio,age,intraoperative blood loss,and wound healing time among groups（P〈0.05）.All goats survived to the end of the experiment.MRI examination showed decreased signal intensity in 3 groups,indicating intervertebral disc degeneration.According to modified Thompson classification method,the degree of intervertebral disc degeneration of group A was significantly higher than that of groups B and C（P〈0.05）,but no significant difference was found between groups B and C（P〈0.05）.Difference was not significant in intervertebral space height before operation among3 groups（P〈0.05）.But after 24 weeks,the intervertebral space height in group A was significantly higher than that in groups B and C（P〈0.05）,and the intervertebral space height loss in group A was significantly lower than that in groups B and C（P〈0.05）.The biomechanical strength in group A was also significantly higher than that in groups B and C（P〈0.05）,but no significant difference was found between group B and group C（P〈0.05）.HE and Masson staining showed good continuity of annulus fibrosus and clear layers in group A;poor continuity of annulus fibrosus and obvious scar tissues were observed in groups B and C.Conclusion Application of working channel may have less destruction of annulus fibrosus,it plays a positive role in the maintenance of biomechanical strength and repair of annulus fibrosus.