全椎板切除-关节突切除术后置入全关节突置换系统对植入节段及相邻节段生物力学的影响。

Effect of the Total Facet Arthroplasty System after complete laminectomy-facetectomy on the biomechanics of implanted and adjacent segments.

作者信息

Phillips Frank M, Tzermiadianos Michael N, Voronov Leonard I, Havey Robert M, Carandang Gerard, Renner Susan M, Rosler David M, Ochoa Jorge A, Patwardhan Avinash G

机构信息

Rush University Medical Center, Chicago, IL, USA.

出版信息

Spine J. 2009 Jan-Feb;9(1):96-102. doi: 10.1016/j.spinee.2008.01.010. Epub 2008 Apr 25.

DOI:10.1016/j.spinee.2008.01.010

PMID:18440280

Abstract

BACKGROUND CONTEXT

Lumbar fusion is traditionally used to restore stability after wide surgical decompression for spinal stenosis. The Total Facet Arthroplasty System (TFAS) is a motion-restoring implant suggested as an alternative to rigid fixation after complete facetectomy.

PURPOSE

To investigate the effect of TFAS on the kinematics of the implanted and adjacent lumbar segments.

STUDY DESIGN

Biomechanical in vitro study.

METHODS

Nine human lumbar spines (L1 to sacrum) were tested in flexion-extension (+8 to -6Nm), lateral bending (+/-6Nm), and axial rotation (+/-5Nm). Flexion-extension was tested under 400 N follower preload. Specimens were tested intact, after complete L3 laminectomy with L3-L4 facetectomy, after L3-L4 pedicle screw fixation, and after L3-L4 TFAS implantation. Range of motion (ROM) was assessed in all tested directions. Neutral zone and stiffness in flexion and extension were calculated to assess quality of motion.

RESULTS

Complete laminectomy-facetectomy increased L3-L4 ROM compared with intact in flexion-extension (8.7+/-2.0 degrees to 12.2+/-3.2 degrees, p<.05) lateral bending (9.0+/-2.5 degrees to 12.6+/-3.2 degrees, p=.09), and axial rotation (3.8+/-2.7 degrees to 7.8+/-4.5 degrees p<.05). Pedicle screw fixation decreased ROM compared with intact, resulting in 1.7+/-0.5 degrees flexion-extension (p<.05), 3.3+/-1.4 degrees lateral bending (p<.05), and 1.8+/-0.6 degrees axial rotation (p=.09). TFAS restored intact ROM (p>.05) resulting in 7.9+/-2.1 degrees flexion-extension, 10.1+/-3.0 degrees lateral bending, and 4.7+/-1.6 degrees axial rotation. Fusion significantly increased the normalized ROM at all remaining lumbar segments, whereas TFAS implantation resulted in near-normal distribution of normalized ROM at the implanted and remaining lumbar segments. Flexion and extension stiffness in the high-flexibility zone decreased after facetectomy (p<.05) and increased after simulated fusion (p<.05). TFAS restored quality of motion parameters (load-displacement curves) to intact (p>.05). The quality of motion parameters for the whole lumbar spine mimicked L3-L4 segmental results.

CONCLUSIONS

TFAS restored range and quality of motion at the operated segment to intact values and restored near-normal motion at the adjacent segments.

摘要

背景

传统上，腰椎融合术用于在广泛手术减压治疗腰椎管狭窄后恢复稳定性。全关节突置换系统（TFAS）是一种旨在恢复运动的植入物，被提议作为全关节突切除术后刚性固定的替代方案。

目的

研究TFAS对植入节段及相邻腰椎节段运动学的影响。

研究设计

生物力学体外研究。

方法

对9个完整的人腰椎标本（L1至骶骨）进行屈伸（+8至-6牛米）、侧弯（±6牛米）和轴向旋转（±5牛米）测试。屈伸测试时施加400牛的跟随预载荷。对标本进行完整状态测试、L3全椎板切除联合L3-L4关节突切除术后测试、L3-L4椎弓根螺钉固定术后测试以及L3-L4 TFAS植入术后测试。在所有测试方向评估活动范围（ROM）。计算屈伸时的中性区和刚度以评估运动质量。

结果

与完整标本相比，全椎板切除-关节突切除使L3-L4在屈伸时的ROM增加（从8.7±2.0度增加到12.2±3.2度，p<0.05），侧弯时（从9.0±2.5度增加到12.6±3.2度，p=0.09）以及轴向旋转时（从3.8±2.7度增加到7.8±4.5度，p<0.05）。椎弓根螺钉固定与完整标本相比使ROM减小，屈伸时为1.7±0.5度（p<0.05），侧弯时为3.3±1.4度（p<0.05），轴向旋转时为1.8±0.6度（p=0.09）。TFAS恢复了完整的ROM（p>0.05），屈伸时为7.9±2.1度，侧弯时为10.1±3.0度，轴向旋转时为4.7±1.6度。融合显著增加了所有剩余腰椎节段的标准化ROM，而TFAS植入导致植入节段及剩余腰椎节段的标准化ROM接近正常分布。关节突切除后高柔韧性区域的屈伸刚度降低（p<0.05），模拟融合后增加（p<0.05）。TFAS将运动参数（载荷-位移曲线）的质量恢复到完整状态（p>0.05）。整个腰椎的运动参数质量与L3-L4节段结果相似。