Acosta Frank L, Buckley Jenni M, Xu Zheng, Lotz Jeffrey C, Ames Christopher P
Department of Neurological Surgery, University of California, San Francisco, California 94143, USA.
J Neurosurg Spine. 2008 Apr;8(4):341-6. doi: 10.3171/SPI/2008/8/4/341.
Increased structural stability is considered sufficient justification for higher-risk surgical procedures, such as circumferential fixation after severe spinal destabilization. However, there is little biomechanical evidence to support such claims, particularly after traumatic lumbar burst fracture. The authors sought out to compare the biomechanical performance of the following 3 fixation strategies for spinal reconstruction after decompression for an unstable thoracolumbar burst fracture: 1) short-segment anterolateral fixation; 2) circumferential fixation; and 3) extended anterolateral fixation.
Thoracolumbar spines (T10-L4) from 7 donors (mean age at death 64+/-6 years; 1 female and 6 males) were tested in pure moment loading in flexion-extension, lateral bending, and axial rotation. Thoracolumbar burst fractures were surgically induced at L-1, and testing was repeated sequentially for each of the following fixation techniques: short-segment anterolateral, circumferential, and extended anterolateral. Primary and coupled 3D motions were measured across the instrumented site (T12-L2) and compared across treatment groups.
Circumferential and extended anterolateral fixations were statistically equivalent for primary and off-axis range-of-motions in all loading directions, and short-segment anterolateral fixation offered significantly less rigidity than the other 2 methods.
The results of this study strongly suggest that extended anterolateral fixation is biomechanically comparable to circumferential fusion in the treatment of unstable thoracolumbar burst fractures with posterior column and posterior ligamentous injury. In cases in which an anterior procedure may be favored for load sharing or canal decompression, extension of the anterior instrumentation and fusion one level above and below the unstable segment can result in near equivalent stability to a 2-stage circumferential procedure.
结构稳定性增强被认为是进行高风险外科手术的充分理由，比如严重脊柱失稳后的环形固定。然而，几乎没有生物力学证据支持此类说法，尤其是在创伤性腰椎爆裂骨折之后。作者旨在比较以下三种用于不稳定胸腰椎爆裂骨折减压术后脊柱重建的固定策略的生物力学性能：1）短节段前外侧固定；2）环形固定；3）延长前外侧固定。
对7名捐赠者（平均死亡年龄64±6岁；1名女性和6名男性）的胸腰椎（T10-L4）进行屈伸、侧屈和轴向旋转的纯力矩加载测试。在L-1处手术诱发胸腰椎爆裂骨折，并依次对以下每种固定技术重复测试：短节段前外侧、环形和延长前外侧。测量器械固定部位（T12-L2）的主要和耦合三维运动，并在各治疗组之间进行比较。
在所有加载方向上，环形固定和延长前外侧固定在主要和离轴运动范围方面在统计学上相当，短节段前外侧固定的刚度明显低于其他两种方法。
本研究结果强烈表明，在治疗伴有后柱和后韧带损伤的不稳定胸腰椎爆裂骨折时，延长前外侧固定在生物力学上与环形融合相当。在因分担负荷或椎管减压而可能更倾向于前路手术的情况下，将前路器械和融合延伸至不稳定节段上下各一个节段，可产生与两阶段环形手术近乎相同的稳定性。
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