腰椎横突间入路椎体间融合术的生物力学评价

目的 观察腰椎横突间入路椎体间融合术(ILIF)及附加椎弓根钉固定后的生物力学稳定性.方法 采用小牛脊柱运动节段标本12具,依序进行不同处理后分为以下7组:(1)正常对照组(IS);(2)左侧小关节切除+椎间融合器植入组(TLIF);(3)TLIF附加同侧椎弓根钉固定组;(4)TLIF附加双侧椎弓根钉固定组;(5)左侧横突间入路椎间融合器植入组(ILIF);(6)ILIF附加同侧椎弓根钉固定组;(7)ILIF附加双侧椎弓根钉固定组.分别测试各组在轴向压缩、前屈、后伸、左右侧屈时的载荷-应变、载荷-位移变化以及轴向刚度和双向扭转稳定性等生物力学指标,并进行统计学比较.结果 所有生物力学指标中ILIF组稳定性均大于TLIF组(P<0.05),在定量扭矩扭角方面差距最大达72%.ILIF+BPSF的稳定性最高,在前屈载荷应变方面较IS组差异最大达53%,而ILIF+HPSF组与ILIF+BPSF组比较差异无统计学意义(P>0.05). 结论 ILIF手术生物力学稳定性优于TLIF手术;ILIF附加同侧椎弓根钉固定与附加双侧椎弓根钉固定生物力学稳定性相当,使用ILIF术式附加侧同椎弓根螺钉固定,可提供较好的即刻稳定性.

Intertransverse lumbar interbody fusion: A biomechanical in vitro study

Objective To assess the relative stability and kinematics of the lumbar segmental stiffness among intertransverse lumbar interbody fusion (ILIF) with or without transpedicular screw rod fixation and transforaminar lumbar interbody fusion (TLIF) with or without transpedicular screw rod fixation.Methods Twelve fresh frozen bovine lumbar functional spinal units (FSU) were prepared for biomechanical test.According to the different treatments,the specimens were divided into 7 groups: (1) intact specimens (IS);(2) specimens were treated by left unilateral facetectomy and had homolateral anatomical threaded cages inserted (TLIF);(3) TLIF with homolateral pedicle screw fixation (TLIF+HPSF);(4) TLIF with bilateral pedicle screw fixation (TLIF+BPSF);(5) specimens had anatomical threaded cages inserted on the left by intertransverse process approach (ILIF);(6) ILIF with homolateral pedicle screw fixation (ILIF+HPSF);(7) ILIF with bilateral pedicle screw fixation (ILIF+BPSF).Data were recorded about load-strain,load-displacement,axial rigidity,twist angle,twist displacement and twist rigidity.Results The stability in ILIF group was greater than in TLIF group,and the most obvious disparity of 72% was in twist angle.In ILIF+BPSF group,there was the most stable,and in flexion load-strain ILIF+BPSF group outweighed IS group 53% at most.There was no significant difference in all indexes between ILIF+HPSF group and ILIF+BPSF group (P>0.05).Conclusion ILIF provides greater biomechanical stability than TLIF,but there was no significant difference in stability between ILIF with unilateral or bilateral pedicle screw fixation.Adequate postoperative stability can be achieved by intertransverse lumbar interbody fusion with unilateral pedicle screw fixation.