短节段脊柱失稳后经撑开复位内固定系统固定后的即刻刚度变化

背景：自行研制脊柱滑脱、骨折撑开复位固定装置，最大特点是它的撑开复位内固定功能，完全融合到钢板设计上，不需过多手术器械来提供，减少手术出血和创伤。 目的：测试短节段猪脊柱标本在完整、失稳后及撑开复位内固定系统（the Distraction Reduction Fixation System，DRFS）内固定后的刚度变化。 设计、时间及地点：对比观察实验，于2004—12／200512在解放军总医院骨科研究所生物力学实验室完成。 材料：选择市购新鲜猪腰椎脊柱标本（T11～S2节段）12具，将标本上下两个节段交叉打入克氏针以利固定，制成腰1～7节段的猪脊柱标本。 方法：测定完整标本在前屈、后伸、侧屈及旋转时的刚度；切除椎间盘、小关节及前后纵韧带松解脊柱，测定其各项运动刚度；用撑开复位内固定系统进行短节段内固定后重复测试各项运动刚度。 主要观察指标：完整、失稳及内固定后脊柱各项运动刚度测试结果。 结果：与完整脊柱的刚度相比，失稳后脊柱各项运动的刚度均明显减少（P〈0．05）；内固定后脊柱各项运动的刚度均明显高于失稳后脊柱（P〈0．05）；内固定后脊柱前屈、侧屈及旋转运动的刚度与完整标本比较差异无显著性意义（P〉0．05），后伸运动的刚度明显高于完整脊柱（P〈0．05）。 结论：从生物力学角度证实了脊柱失稳后经撑开复位内固定系统短节段固定后的即刻刚度明显增高。但因其为后路固定，固定后脊柱标本与完整脊柱标本相比后伸活动受限。

Stiffness changes in short-segment spine after destabilizing by using the Distraction Reduction Fixation System

BACKGROUND:Self-made Distraction Reduction Fixation System is characterized by Distraction Reduction Fixation functions,which can completely fuse to the design of steel plate,and by no need to provide many surgical instruments,by reduction of bleeding and trauma.OBJECTIVE:To test changes in the stiffness of porcine short spinal segments in integrity and following destabilizing and internal fixation of the Distraction Reduction Fixation System.DESIGN,TIME AND SETTING:The control observation experiment was performed at the Laboratory of Biodynamics,Institute of Onhopedics,General Hospital of Chinese PLA from December 2004 to December 2005.MATERIALS:Twelve fresh porcine lumbar spines(T11-S2 segments)were bought from a market.Upper and lower segments were crossed and inserted with Kirschner wire to make porcine spine samples of the L1-7 segments.METHODS:Stiffness of intact samples was recorded during forward-bending,backward-bending,lateral-bending and axial rotation.Intervertebral discs,facet ioints,anterior and posterior longitudinal ligaments were removed to loose the spine.Stifrness of each motion was measured.Stiffness tests were repeated again after internal fixation on short segments using Distraction Reduction Fixation System.MAIN OUTCOME MEASURES:Stiffness in the intact,unstable and internal fixed spines during each motion.RESULTS:The stiffness iu unstable porcine spine were significantly lower than those in intact porcine spine(P<0.05),but the stiffness after internal fixation was significantly higher than in unstable porcine spine(P<0.05).No significant difference was detected in stifiness during forward-bending,lateral-bending and axial rotation(P>0.05)except that it was significantly higher during backward.bending after internal fixation compared with the intaet spine(P<0.05).CONCLUSION:Biodynamics confirms that the stiffness in short-segment fixation porcine after using Distraction Reduction Fixation System is markedly increased than in unstable porcine spine,except during backward-bending,which is comparable with that in intact porcine spine.