Kwon Anthony J, Hunter William D, Moldavsky Mark, Salloum Kanaan, Bucklen Brandon
Total Spine Specialists, Charlotte, North Carolina;
Gaston Memorial Hospital, Gastonia, North Carolina; and.
J Neurosurg Spine. 2016 May;24(5):727-33. doi: 10.3171/2015.10.SPINE15450. Epub 2016 Jan 29.
OBJECTIVE The lateral transpsoas approach to the lumbar spine is a well-defined procedure for the management of discogenic spinal pathology necessitating surgical intervention. Intervertebral device subsidence is a postoperative clinical risk that can lead to recurrence of symptomatic pathology and the need for surgical reintervention. The current study was designed to investigate static versus expandable lateral intervertebral spacers in indirect decompression for preserving vertebral body endplate strength. METHODS Using a cadaveric biomechanical study and a foam-block vertebral body model, researchers compared vertebral body endplate strength and distraction potential. Fourteen lumbar motion segments (7 L2-3 and 7 L4-5 specimens) were distributed evenly between static and expandable spacer groups. In each specimen discectomy was followed by trialing and spacer impaction. Motion segments were axially sectioned through the disc, and a metal stamp was used to apply a compressive load to superior and inferior vertebral bodies to quantify endplate strength. A paired, 2-sample for means t-test was performed to determine statistically significant differences between groups (p ≤ 0.05). A foam-block endplate model was used to control simulated disc tension when a spacer with 2- and 3-mm desired distraction was inserted. One-way ANOVA and a post hoc Student Newman-Keuls test were performed (p ≤ 0.05) to determine differences in distraction. RESULTS Both static and expandable spacers restored intact neural foramen and disc heights after device implantation (p > 0.05). Maximum peak loads at endplate failure for static and expandable spacers were 1764 N (± 966 N) and 2284 N (± 949 N), respectively (p ≤ 0.05). The expandable spacer consistently produced greater desired distraction than was created by the static spacer in the foam-block model (p ≤ 0.05). Distraction created by fully expanding the spacer was significantly greater than the predetermined goals of 2 mm and 3 mm (p ≤ 0.05). CONCLUSIONS The current investigation shows that increased trialing required for a static spacer may lead to additional iatrogenic endplate damage, resulting in less distraction and increased propensity for postoperative implant subsidence secondary to endplate disruption.
目的 腰椎经腰大肌外侧入路是一种用于治疗需要手术干预的椎间盘源性脊柱病变的明确手术方法。椎间装置下沉是一种术后临床风险，可导致症状性病变复发以及需要再次手术干预。本研究旨在探讨静态与可扩张外侧椎间融合器在间接减压中对保留椎体终板强度的作用。方法 通过尸体生物力学研究和泡沫块椎体模型，研究人员比较了椎体终板强度和撑开潜力。14个腰椎运动节段（7个L2-3和7个L4-5标本）平均分配到静态和可扩张融合器组。在每个标本中，先进行椎间盘切除术，然后进行试模和融合器植入。运动节段通过椎间盘进行轴向切片，使用金属压模对上下椎体施加压缩载荷以量化终板强度。进行配对双样本均值t检验以确定组间的统计学显著差异（p≤0.05）。当插入期望撑开2毫米和3毫米的融合器时，使用泡沫块终板模型来控制模拟椎间盘张力。进行单因素方差分析和事后Student Newman-Keuls检验（p≤0.05）以确定撑开差异。结果 静态和可扩张融合器植入后均恢复了完整的神经孔和椎间盘高度（p>0.05）。静态和可扩张融合器终板破坏时的最大峰值载荷分别为1764 N（±966 N）和2284 N（±949 N）（p≤0.05）。在泡沫块模型中，可扩张融合器始终比静态融合器产生更大的期望撑开（p≤0.05）。完全撑开融合器产生的撑开明显大于预定的2毫米和3毫米目标（p≤0.05）。结论 目前的研究表明，静态融合器所需的更多试模可能导致额外的医源性终板损伤，导致撑开减少以及术后因终板破坏继发植入物下沉的倾向增加。
