The role of anteromedial foraminotomy and the uncovertebral joints in the stability of the cervical spine - A biomechanical study
The role of anteromedial foraminotomy and the uncovertebral joints in the stability of the cervical spine - A biomechanical study
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DOI：
10.1097/00007632-199807150-00011
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发表时间：
1998-07-15
期刊：
影响因子：
3
通讯作者：
McAfee, PC
中科院分区：
文献类型：
--
作者：
Kotani, Y;McNulty, PS;McAfee, PC
研究设计。利用人体身体脊柱研究颈椎钩椎关节的生物力学作用。连续切除颈椎钩椎关节，包括临床前内孔切开术，然后在每一阶段切除后进行生物力学测试。目的：阐明颈椎钩椎关节和临床前内孔切开术的生物力学作用及其对椎间植骨稳定性的影响。虽然颈椎钩椎关节的生物力学作用一直被认为是屈曲和伸展的引导机制和后平移和侧弯的限制机制，但还没有研究量化这一作用。根据定量解剖学研究的结果，钩椎关节存在解剖差异，这取决于椎体水平、关节角度和关节的相对高度。14个位于C3-C4和C6-C7的人类功能脊柱单位接受了顺序的钩椎关节切除，每一阶段都在生物力学测试之后进行。钩椎关节在解剖学上每侧分为三部分：后孔部分、后半部分和前半部分。加载方式包括扭转、屈曲、；、伸展和侧弯。在每次钩椎关节切除手术后，还对模拟前路植骨结构进行了测试。在所有加载模式下，序列钩椎关节切除后稳定性均有显著变化(P<；0.05)。钩椎关节的生物力学贡献按以下顺序递减：后孔部分，后半部分，前半部分。在伸展过程中，单侧和双侧椎间孔切开术对脊髓功能单位的稳定性影响最大，导致功能脊柱单位的僵硬程度分别下降30%和36%。在扭转和侧弯方面影响较小。序贯切除后，C3-C4和C6-C7扭转刚度的降低有统计学意义(P<；0.05)。在每次椎孔切开后的屈曲和侧弯过程中，模拟植骨结构的硬度逐渐降低(P<；0.05)。植骨高度增加了79%，恢复了椎间隙切开前的稳定性。这是首次对钩椎关节在颈椎节段稳定性中的生物力学作用及其在各个椎间节段的影响进行量化研究。由于钩椎关节的解剖差异，其效果也有所不同。钩椎关节的生物力学功能主要包括伸展和侧弯运动的调节，其次是扭转运动，主要由后钩椎关节提供。这项研究强调了由于手术过程中钩椎关节破坏或肿瘤病变所致的额外节段不稳定的临床评估。
Study Design. The biomechanical role of the cervical uncovertebral joint was investigated using human cadaveric spines. Sequential resection of cervical uncovertebral joints, including clinical anteromedial foraminotomy, was conducted, followed by biomechanical testing after each stage of resection.Objectives. To clarify the biomechanical role of uncovertebral joints and clinical anteromedial foraminotomy in the cervical spine and their effects on inter-body bone graft stability.Summary of Background Data. Although the biomechanical role of the cervical uncovertebral joints has been considered to be that of a guiding mechanism in flexion and:extension and a limiting mechanism in posterior translation and lateral bending, there have been no studies quantifying this role. According to results in quantitative anatomic studies, anatomic variations exist in uncovertebral joints, depending on the vertebral level, articular angulation, and relative height of the joints.Methods. Fourteen human functional spinal units at C3-C4 and C6-C7 underwent sequential uncovertebral joint resection, with each stage of resection followed by biomechanical testing. The uncovertebral joint was divided anatomically into three parts on each side: the posterior foraminal part, the posterior half, and the anterior half. The loading modes included torsion, flexion,;; extension, and lateral bending. A simulated anterior bone graft construct was also tested after each uncovertebral joint resection procedure.Results. Significant changes in stability were observed after sequential uncovertebral joint resection in all loading modes (P< 0.05). The biomechanical contribution of uncovertebral joints decreased in the following order: the posterior foraminal part, the posterior half,and the anterior half. Unilateral and bilateral foraminotomy most affected the stability of the functional spinal unit during extension, causing a 30% and 36% decrease in stiffness of the function spinal unit, respectively.The effect was less in torsion and lateral bending. After sequential resection, there was a statistically significant difference between decreases in torsional stiffness at C3-C4 and C6-C7 (P < 0.05). The stiffness of the simulated bone graft construct decreased progressively during flexion and lateral bending after each foraminotomy ( P < 0.05). Increased bone graft height of 79% returned stability to the preforaminotomy level.Conclusions. This is the first study to quantitate the biomechanical role of uncovertebral joints in cervical segmental stability and the effect at each intervertebral level. The effect differs because of anatomic variations in uncovertebral joints. The major biomechanical function of uncovertebral joints includes the regulation of extension and lateral bending motion, followed by torsion, which is mainly provided by the posterior uncovertebral joints. This study highlights the clinical assessment of additional segmental instability attributed to destruction of the uncovertebral joints during surgical procedures or by neoplastic lesions.