Biomechanical evaluation of total disc replacement arthroplasty:: An in vitro human cadaveric model
Biomechanical evaluation of total disc replacement arthroplasty:: An in vitro human cadaveric model
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DOI：
10.1097/01.brs.0000092209.27573.90
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发表时间：
2003-10-15
期刊：
影响因子：
3
通讯作者：
McAfee, PC
中科院分区：
文献类型：
--
作者：
Cunningham, BW;Gordon, JD;McAfee, PC
研究设计。这项体外生物力学研究的目的是量化全椎间盘置换术与传统稳定技术相比的多向椎间运动学。目的。使用体外人体尸体模型，主要目的是比较全椎间盘、关节成形术与传统螺纹融合笼和单级脊柱器械经椎弓根固定增强的笼的多向灵活性特性并绘制全椎间盘的椎间旋转中心图。背景数据摘要。与稳定手术节段的仪器系统相比，使用运动保持植入物需要更好地了解它们的比较生物力学特性。方法。本次研究中使用了总共八个人体尸体腰骶棘（L2 至骶骨），并在以下 L4-L5 重建条件下进行了生物力学评估：1）完整的脊柱； 2）SB Charite椎间盘假体； 3）比克保持架； 4) BAK 融合器 + ISOLA 椎弓根螺钉/杆固定（前后路）。上（L3-L4）和下（L5-S1）椎间水平仍未用仪器来量化相邻水平特性。多向灵活性包括轴向旋转、屈伸和侧向弯曲中的纯、无约束力矩 (+/-8 Nm)，并对手术和邻近水平的运动范围和中立区进行量化，并将其标准化为完整的脊柱状况。 结果。与完整状态相比，SB Charite 假体的轴向旋转运动范围平均增加了 44%（P < 0.05），而 BAK 和前后重建的运动范围分别减少了 29% 和 80%（P < 0.05）。 SB Charite 与 BAK 和联合后路重建有显着差异 (P < 0.05)。屈伸表明，与完整椎间盘相比，SB Charite 的运动范围略有增加 (3%) (P > 0.05)，而与完整和 SB Charite 条件相比，BAK 和前后稳定组导致运动范围显着减小 (BAK = 57%，前后 = 93%) (P < 0.05)。根据屈伸X线照片，仅在以下情况下，椎间旋转中心位于手术椎间盘的后三分之一：SB Charite重建和完整脊柱状态；具有生理椎间平移的明确证据（完整的 2.06 +/- 77 毫米；SB III = 1.9 +/- 0.98 毫米）。结论。全椎间盘关节置换术是椎间盘源性脊柱病理外科治疗的下一个前沿。 SB Charite 将屈伸和侧向弯曲的运动恢复到完整节段的水平，并增加了轴向旋转的运动。装置植入所需的前环切除和假体的无约束设计解释了这种旋转变化。正常的腰椎屈伸旋转轴是椭圆形而不是单个点。只有椎间盘置换术而不是椎弓根器械或 BAK 椎间器械才能保留手术和相邻椎间盘水平的节段运动的运动学特性和正常映射。
Study Design. This in vitro biomechanical study was undertaken to quantify the multidirectional intervertebral kinematics following total disc replacement arthroplasty compared to conventional stabilization techniques.Objective. Using an in vitro human cadaveric model, the primary objective,was to compare the multidirectional flexibility properties and map the center of intervertebral rotation of total disc, arthroplasty versus conventional threaded fusion cages and cages augmented with transpedicular fixation for single-level spinal instrumentation.Summary of Background Data. The utilization of motion-preserving implants versus instrumentation systems, which stabilize the operative segments, necessitates improved understanding of their comparative biomechanical properties.Methods. A total of eight human-cadaveric lumbosacral spines (L2 to sacrum) were utilized in this investigation and biomechanically evaluated under the following L4-L5 reconstruction conditions: 1) intact spine; 2) SB Charite disc prosthesis; 3) BAK cages; and 4) BAK cages + ISOLA pedicle screw/rod fixation (anteroposterior). The superior (L3-L4) and inferior (L5-S1) intervertebral levels remained uninstrumented to quantify adjacent level properties. Multidirectional flexibility included pure, unconstrained moments (+/-8 Nm) in axial rotation, flexion-extension, and lateral bending, with quantification of the operative and adjacent level range of motion and neutral zone, which were normalized to the intact spine condition.Results. The SB Charite prosthesis indicated an average percentage increase in axial rotation range of motion by 44% compared to the intact, condition (P < 0.05), whereas the BAK and anteroposterior reconstructions decreased range of motion by 29% and 80%, respectively (P< 0.05). The SB Charite was significantly different from BAK and combined ariteroposterior reconstructions (P < 0.05). Flexion-extension indicated a minor increase in range of motion for the SB Charite (3%) versus the intact disc (P > 0.05), whereas the BAK and anteroposterior stabilization groups resulted in significant decreases in range,of motion (BAK = 57%, anteroposterior = 93%) (P < 0.05) when compared to the intact and SB Charite, conditions. Based on flexion-extension radiographs, the intervertebral centers of rotation were in the posterior one-third of the operative intervertebral disc only for the: SB Charite reconstruction and intact spine condition; with, definitive evidence of physiologic intervertebral translation (intact 2.06 +/- 77 mm; SB III = 1.9 +/- 0.98 mm).Conclusions. Total disc arthroplasty serves as the next., frontier in the surgical management of discogenic spinal pathology. The SB Charite restored motion to the level of the intact segment in flexion-extension and lateral bending and increased motion in axial rotation. The anterior annular resection necessary for device implantation and unconstrained design of the prosthesis account for this change in rotation. The normal lumbar flexion-extension axis of rotation is an ellipse rather than a single point. Only disc replacement rather than pedicle instrumentation or BAK interbody instrumentation preserves the kinematic properties and normal mapping, of segmental, motion at the operative and adjacent intervertebral-disc levels.