PLIF和ALIF对相邻节段生物力学影响的比较

目的比较PLIF和ALIF及附加椎弓根螺钉后相邻节段的力学性能。方法采用10具小牛腰椎标本,随机选5具为对照组,将10具标本分为L4/L5PLIF和ALIF单纯融合组及附加内固定组,比较L3/L4节段的应变、强度和位移。结果两种融合方法在附加内固定前后比对照组,应变和位移都增加,强度降低(P<0.01),两组间以ALIF组变化最大,PLIF最小(P<0.05);在内固定前后配对比较,附加内固定后应变、位移增加,强度降低(P<0.05)。结论PLIF和ALIF单纯融合及附加内固定有增加上位节段退变的趋势,以ALIF较为明显。附加内固定后比单纯融合有增加退变的趋势。

Comparison of the biomechanical effects of PLIF and ALIF on adjacent segment

Objective To compare the biomechanical effects on the adjacent segment of posterior lumbar interbody fusion (PLIF) and anterior lumbar interbody fusion (ALIF) with and without pedicle screw fixation. Methods Ten one-month-old bovine lumbar specimens were tested biomechanically and divided into two groups randomly. One group was the control group, and another group was PLIF and ALIF on L_4/L_5 with and without pedicle screw fixation. Then to compare the strain, strength and bias of L_3/L_4 between the two groups. ResultsThe experimental group was compared with and without pedicle screw fixation, and the results were the same: the mean strain and bias of the adjacent segment both increased and the mean strength decreased ( P <0.01). The change of the results of ALIF group with and without pedicle screw fixation was bigger than that of PLIF group ( P <0.05). Compared with and without pedicle screw fixation, the mean strain and bias of PLIF and ALIF with that significantly increased, and the mean strength decreased ( P <0.05). Conclusion PLIF and ALIF with and without pedicle screw fixation may lead to degeneration of the superior segment. The probability of ALIF is bigger than that of PLIF and the probability with pedicle screw fixation is also bigger than without that.