不同椎间植骨高度对颈椎稳定性影响的实验研究

Impact of intervertebral graft height on biomechanical stability of cervical vertebrae，an experimental study

中文关键词:  颈椎  椎间高度  植骨  生物力学

英文关键词:Cervical  Intervertebral height  Graft  Biomechanics

中文摘要:

  【摘要】 目的：观察下颈椎前路单椎间隙减压后不同高度植骨对颈椎即刻运动稳定性的影响，为临床上选择适宜的植骨高度提供依据。方法：采用6例新鲜成人尸体颈椎标本，取三面皮质骨髂脊植骨块，对完整状态、C5/6节段椎间隙减压术后应用不同高度骨块（基准高度的100%、120%、140%、160%）行椎间植骨5种状态下进行生物力学测试。在生物材料测试机上加载前屈后伸、左右侧屈、左右轴向旋转的三维运动；计算机图像处理软件测量C5/6节段在各状态下的三维运动范围；进行各状态间的多重比较分析。结果：6例标本C5/6椎间隙植骨的基准高度平均为6.86mm。所有骨块植骨成功，但160％基准高度植骨时骨块置入较困难，且1例标本出现了椎间隙前方残余软组织的撕裂。1例标本在基准高度植骨状态测定屈伸过程中出现了植骨块移位，但在测试过程中均无植骨块脱出。统计分析表明，140%和160%基准高度植骨时较基准高度植骨时C5/6节段前屈后伸、左右侧屈活动度明显减小（P＜0.05），但两者间无显著性差异（P＞0.05）；160％基准高度植骨时C5/6节段的左右侧屈活动度较完整状态及120％基准高度植骨时明显减少（P＜0.05）；其余各状态间两两比较均无显著性差异（P＞0.05）。结论：下颈椎单椎间隙减压后，撑开植骨可增加手术节段的即刻运动稳定性，理想的植骨高度为140%基准高度。

英文摘要:

  【Abstract】 Objective：To study the impact of intervertebral graft height on immediate biomechanical stability of lower cervical spine after Smith-Robinson discectomy and determine the optimal graft height.Method：Six fresh-frozen human cadaveric cervical spines were used in this series，tricortical graft from iliac crest bone were harvested，and specimens were tested in five conditions，normal（specimens with intact discs） and different graft height（120%，140%，160% of baseline height） after Smith-Robinson discectomy.Each specimens were subjected to flexion-extension，lateral bending and axial rotation in material test system（MTS，858 Mini Bionix，MTX corporation），loaded with 1.5N·m.Geomagic studio 5.0 soft was applied to splicing the image obtained from realscan USB soft.Finally，the data for each state was collected and processed for One-way ANOVA by SPSS 13.0. LSD test was used to determine the statistical significance of differences.Result：The mean baseline height graft after Smith-Robinson anterior cervical discectomy was 6.86mm.No bone subsidence into vertebrae，end-plates and grafts during the experimentation were noted，implantation of 160% baseline graft appeared more difficult and the laceration of annular ligament occurred in one.Minor graft displacement happened in one case when measuring the motion of flexion and extension at the state of 100% baseline height，no graft extrusion was noted in any specimens.Statistical analysis indicated that the range of motion in flexion，extension and lateral bending of C5/6 decreased significantly at 140% baseline and 160% baseline compared with the baseline height（P<0.05），but no statistical significance were noted between 140% baseline height and 160% baseline height（P>0.05）.The range of motion in lateral bending of C5/6 decreased significantly at 160% baseline height compared with 120% baseline height and the normal state（P<0.05），the rest groups did not show any statistical difference at any direction（P＞0.05）.Conclusion：Distraction after Smith-Robinson anterior cervical discectomy plays an important role in the immediate biomechanical stability of lower cervical spine，and the ideal graft height after single discectomy may be 140% baseline.