Tempel Zachary J, McDowell Michael M, Panczykowski David M, Gandhoke Gurpreet S, Hamilton D Kojo, Okonkwo David O, Kanter Adam S
J Neurosurg Spine. 2018 Jan;28(1):50-56. doi: 10.3171/2017.5.SPINE16427. Epub 2017 Nov 10.
OBJECTIVE Lateral lumbar interbody fusion (LLIF) is a less invasive surgical option commonly used for a variety of spinal conditions, including in high-risk patient populations. LLIF is often performed as a stand-alone procedure, and may be complicated by graft subsidence, the clinical ramifications of which remain unclear. The aim of this study was to characterize further the sequelae of graft subsidence following stand-alone LLIF. METHODS A retrospective review of prospectively collected data was conducted on consecutive patients who underwent stand-alone LLIF between July 2008 and June 2015; 297 patients (623 levels) met inclusion criteria. Imaging studies were examined to grade graft subsidence according to Marchi criteria, and compared between those who required revision surgery and those who did not. Additional variables recorded included levels fused, DEXA (dual-energy x-ray absorptiometry) T-score, body mass index, and routine demographic information. The data were analyzed using the Student t-test, chi-square analysis, and logistic regression analysis to identify potential confounding factors. RESULTS Of 297 patients, 34 (11.4%) had radiographic evidence of subsidence and 18 (6.1%) required revision surgery. The median subsidence grade for patients requiring revision surgery was 2.5, compared with 1 for those who did not. Chi-square analysis revealed a significantly higher incidence of revision surgery in patients with high-grade subsidence compared with those with low-grade subsidence. Seven of 18 patients (38.9%) requiring revision surgery suffered a vertebral body fracture. High-grade subsidence was a significant predictor of the need for revision surgery (p < 0.05; OR 12, 95% CI 1.29-13.6), whereas age, body mass index, T-score, and number of levels fused were not. This relationship remained significant despite adjustment for the other variables (OR 14.4; 95% CI 1.30-15.9). CONCLUSIONS In this series, more than half of the patients who developed graft subsidence following stand-alone LLIF required revision surgery. When evaluating patients for LLIF, supplemental instrumentation should be considered during the index surgery in patients with a significant risk of graft subsidence.
目的 腰椎外侧椎间融合术（LLIF）是一种常用于多种脊柱疾病的微创手术选择，包括高危患者群体。LLIF通常作为独立手术进行，可能会并发移植物沉降，其临床后果尚不清楚。本研究的目的是进一步描述独立LLIF术后移植物沉降的后遗症。方法 对2008年7月至2015年6月期间连续接受独立LLIF手术的患者进行前瞻性收集数据的回顾性研究；297例患者（623个节段）符合纳入标准。根据马尔基标准对影像学研究进行检查以对移植物沉降进行分级，并在需要翻修手术的患者和不需要翻修手术的患者之间进行比较。记录的其他变量包括融合节段、双能X线吸收法（DEXA）T值、体重指数和常规人口统计学信息。使用Student t检验、卡方分析和逻辑回归分析对数据进行分析，以确定潜在的混杂因素。结果 在297例患者中，34例（11.4%）有影像学证据显示沉降，18例（6.1%）需要翻修手术。需要翻修手术的患者的沉降分级中位数为2.5，而不需要翻修手术的患者为1。卡方分析显示，与低级别沉降患者相比，高级别沉降患者的翻修手术发生率显著更高。18例需要翻修手术的患者中有7例（38.9%）发生椎体骨折。高级别沉降是需要翻修手术的显著预测因素（p < 0.05；OR 12，95% CI 1.29 - 13.6），而年龄、体重指数、T值和融合节段数量则不是。尽管对其他变量进行了调整，但这种关系仍然显著（OR 14.4；95% CI 1.30 - 15.9）。结论 在本系列研究中，独立LLIF术后发生移植物沉降的患者中，超过一半需要翻修手术。在评估LLIF患者时，对于有显著移植物沉降风险的患者，在初次手术时应考虑附加内固定。
