胸腰椎前路K形钢板内固定系统的生物力学评价

目的：对胸腰椎前路K形钢板内固定系统（K－plate）进行生物力学稳定性评价。方法：6例新鲜成人尸体胸腰椎（T11－L3）标本，制成前、中柱损伤模型，椎体间模拟植骨后，分别以－Zplate、K－plate固定，采用脊柱三维运动试验系统测试完整、损伤、Z-plate和K-plate等4种状态下脊柱节段的运动范围（ROM）。结果：K-plate固定后，前屈、后伸、左侧弯、右侧变运动方向上ROM与完整、损伤状态之间差异有显著性（P＜0．05）；左、右轴向旋转运动方向上ROM与损伤状态之间差异有显著性（P＜0．05），但与完整状态之间差异无显著性（P＞0．05）。Z－plate、K－plate固定状态之间6个运动方向上ROM差异均无显著性（P＞0．05）。结论：胸腰椎前路K形钢板内固定系统能有效恢复失稳胸腰椎的稳定性。

Biomechanical evaluation of an anterior thoracolumbar K-plate fixation system

Objective: To evaluate the biomechanical stability of an anterior thoracolumbar K plate fixation system for unstable human cadaveric spine. Methods: Six fresh thoracolumbar spines (T 11 L 3) were used in this study. After instability created from injury of anterior and middle columns in all six specimens, Z plate (Sofamor Danek Co.) and K plate, combined with interbody grafting, were used to reconstruct the unstable segments respectively. Using a three dimensional motion measurement system, the ranges of motion (ROM) were obtained in each specimen under four different testing states including intact, injured spine, Z plate fixation and K plate fixation. Results: The ROM after K plate fixation showed significantly less than that of intact or injured spine ( P <0.05) in flexion, extension, lateral bending, and injured spine in axial rotation ( P <0.05). K plate fixation provided similar stability with intact specimen in axial rotation. No statistical differences of ROM in all six motions were found between K plate and Z plate ( P > 0.05) . Conclusion: The present study supports that this K plate fixation system can effectively restore biomechanical stability for unstable thoracolumbar spine.