经仪器测量和置入棘突间 spacer 后脊柱相邻节段的生物力学研究。

A biomechanical study of the instrumented and adjacent lumbar levels after In-Space interspinous spacer insertion.

机构信息

Department of Neurosurgery, Stanford University Medical Center, Stanford, California, USA.

出版信息

J Neurosurg Spine. 2010 May;12(5):560-9. doi: 10.3171/2009.11.SPINE08668.

DOI:10.3171/2009.11.SPINE08668

PMID:20433305

Abstract

OBJECT

Interspinous process implants are becoming more common for the treatment of lumber disc degeneration. The authors undertook this study to evaluate the effect of the In-Space interspinous spacer on the biomechanics of the lumbosacral spine.

METHODS

Seven L2-S1 cadaver spines were physiologically loaded in extension, flexion, lateral bending, and axial rotation modes. The range of motion (ROM) and intervertebral disc pressure (DP) at the level implanted with an In-Space device and at adjacent levels were measured under 4 experimental conditions. Biomechanical testing was carried out on 7 sequentially prepared specimens in the following states: 1) the intact L2-S1 cadaver spine and 2) the L2-S1 cadaver specimen implanted with an In-Space interspinous spacer at L3-4 (Group 1), 3) after an additional L3-4 discectomy (with the In-Space interspinous spacer still in place) (Group 2), and finally, 4) after removal of the In-Space interspinous spacer, leaving only the discectomized (that is, destabilized) spine model (Group 3).

RESULTS

The extension ROM at the implanted level after experimental conditions 2 and 3 above was statistically significantly reduced. An increase of ROM at the adjacent levels compensated for the reduction at the implanted level. However, there was no statistically significant change in ROM in any of the other modes of motion at any of the levels studied. Likewise, the DP reduction at L3-4 during extension was statistically significant, but in all other modes of motion, there was no statistically significant change in DP at any measured level. The In-Space interspinous spacer statistically significantly reduced the ROM of the L3-4 motion segment in Groups 1 and 2 (extension: 67%, p = 0.018 and 70%, p = 0.018; flexion: 72%, p = 0.028 and 80%, p = 0.027). After placement of the In-Space interspinous spacer, the DP was decreased at L3-4 in extension for Groups 1 and 2 in the posterior anular region (63%, p = 0.028; 59%, p = 0.043), Group 2 in the center region (73%, p = 0.028), and Groups 1 and 2 in the anterior anular region (57%, p = 0.018; 60%, p = 0.018).

CONCLUSIONS

The In-Space interspinous spacer both stabilizes the spine and reduces the intervertebral DP at the instrumented level during extension. The biomechanics for other modes of motion and at the adjacent levels are not affected statistically significantly, however. The device thus performed as intended. It significantly stabilized the motion segments at the instrumented level, but not at the segment adjacent to the instrumented level.

摘要

目的

棘突间植入物在治疗腰椎间盘退变方面越来越常见。作者进行这项研究是为了评估 In-Space 棘突间间隔物对腰骶脊柱生物力学的影响。

方法

7 个 L2-S1 尸体脊柱在伸展、弯曲、侧屈和轴向旋转模式下进行生理加载。在 4 种实验条件下，测量植入 In-Space 装置的水平和相邻水平的运动范围（ROM）和椎间盘压力（DP）。对 7 个连续制备的标本进行生物力学测试，处于以下状态：1）完整的 L2-S1 尸体脊柱和 2）L2-S1 尸体标本在 L3-4 处植入 In-Space 棘突间间隔物（组 1），3）在 L3-4 处进行额外的椎间盘切除术（同时保留 In-Space 棘突间间隔物）（组 2），最后，4）取出 In-Space 棘突间间隔物，仅保留椎间盘切除术（即不稳定）脊柱模型（组 3）。

结果

上述实验条件 2 和 3 后，植入水平的伸展 ROM 统计学上显著降低。相邻水平 ROM 的增加补偿了植入水平的减少。然而，在研究的任何水平的任何其他运动模式中，ROM 均无统计学意义的变化。同样，在伸展时 L3-4 的 DP 降低具有统计学意义，但在所有其他运动模式中，在任何测量水平的 DP 均无统计学意义的变化。In-Space 棘突间间隔物在组 1 和 2 中统计学上显著降低了 L3-4 运动节段的 ROM（伸展：67%，p=0.018 和 70%，p=0.018；弯曲：72%，p=0.028 和 80%，p=0.027）。在放置 In-Space 棘突间间隔物后，组 1 和 2 的 L3-4 在伸展时的 DP 在后环区减少（63%，p=0.028；59%，p=0.043），组 2 在中央区减少（73%，p=0.028），以及组 1 和 2 在前环区减少（57%，p=0.018；60%，p=0.018）。