Objective: To investigate the effects of percutaneous cement discoplasty (PCD) and percutaneous cement interbody fusion (PCIF) on spinal stability by in vitro biomechanical tests.
Methods: Biomechanical test was divided into intact (INT) group, percutaneous lumbar discectomy (PLD) group, PCD group, and PCIF group. Six specimens of L 4, 5 (including vertebral bodies and intervertebral discs) from fresh male cadavers were taken to prepare PLD, PCD, and PCIF specimens, respectively. Before treatment and after the above treatments, the MTS multi-degree-of-freedom simulation test system was used to conduct the biomechanical test. The intervertebral height of the specimen was measured before and after the axial loading of 300 N, and the difference was calculated. The range of motion (ROM) and stiffness of the spine in flexion, extension, left/right bending, and left/right rotation under a torque of 7.5 Nm were calculated.
Results: After axial loading, the change of intervertebral height in PLD group was more significant than that in other three groups ( P<0.05). Compared with INT group, the ROM in all directions significantly increased and the stiffness significantly decreased in PLD group ( P<0.05). Compared with INT group, the ROM of flexion, extension, and left/right rotation in PCD group significantly increased and the stiffness significantly decreased ( P<0.05); compared with PLD group, the ROM of flexion, extension, and left/right bending in PCD group significantly decreased and the stiffness significantly increased ( P<0.05). Compared with INT group, ROM of left/right bending in PCIF group significantly decreased and stiffness significantly increased ( P<0.05); compared with PLD group, the ROM in all directions significantly decreased and the stiffness significantly increased ( P<0.05); compared with PCD group, the ROM of flexion, left/right bending, and left/right rotation significantly decreased and stiffness significantly increased ( P<0.05).
Conclusion: Both PCD and PCIF can provide good biomechanical stability. The former mainly affects the stiffness in flexion, extension, and bending, while the latter is more restrictive on lumbar ROM in all directions, especially in bending and rotation.
目的: 通过体外生物力学试验，比较经皮骨水泥椎间盘成形术（percutaneous cement discoplasty，PCD）以及经皮骨水泥椎间融合术（percutaneous cement interbody fusion，PCIF）对脊柱稳定性的影响。.
方法: 生物力学试验分为正常对照（intact，INT）组、经皮腰椎间盘切除（percutaneous lumbar discectomy，PLD）组、PCD组、PCIF组。取6具新鲜成年男性L 4、5运动节段标本（包括椎体及椎间盘），分别制作PLD、PCD以及PCIF标本。分别于处理前以及上述处理后，采用MTS多自由度模拟测试系统进行生物力学测试，包括轴向加载300 N压力前后标本高度，并计算差值；加载7.5 Nm扭矩下前屈、后伸、左/右侧弯以及左/右旋转的脊柱活动度（range of motion，ROM）及刚度。.
结果: 轴向加载压力后，PLD组椎间高度变化大于其他组（ P<0.05）。PLD组与INT组比较，各向ROM均增大，刚度均减小（ P<0.05）。PCD组与INT组比较，前屈、后伸、左/右旋转ROM均增大，刚度减小（ P<0.05）；与PLD组比较，前屈、后伸、左/右侧弯ROM均减小，刚度增大（ P<0.05）。PCIF组与INT组比较，左/右侧弯ROM均减小，刚度增大（ P<0.05）；与PLD组比较，各向ROM均减小、刚度增大（ P<0.05）；与PCD组比较，前屈、左/右侧弯、左/右旋转ROM均减小，刚度增大（ P<0.05）。.
结论: PCD和PCIF均能减小腰椎运动节段ROM、增加刚度，其中前者主要影响屈伸和侧弯刚度，后者对腰椎各向ROM，尤其是侧弯及旋转方向限制性更强。.
Keywords: Lumbar degeneration; biomechanics; percutaneous cement discoplasty; percutaneous cement interbody fusion; spinal stability.