PURPOSE Quantitative computed tomography (QCT) is an alternate imaging method to dual X-ray absorptiometry to measure bone mineral density (BMD). One advantage of QCT is that it allows site-specific volumetric BMD (vBMD) measurements in a small region. In this study, we utilized site-specific, endplate vBMD (EP-vBMD) as a potential predictive marker of severe cage subsidence in standalone lateral lumbar interbody fusion (SA-LLIF) patients and conducted a retrospective comparative study between EP-vBMD and trabecular vBMDs (Tb-vBMD) in the vertebrae. METHODS Patients undergoing SA-LLIF from 2007 to 2016 were retrospectively reviewed. EP-vBMD was defined as the average of the upper and lower endplate volumetric BMDs measured in cortical and trabecular bone included in a 5-mm area of interest beneath the cage contact surfaces. We compared Tb-vBMDs and EP-vBMDs between disk levels that had severe cage subsidence and levels with no severe subsidence. RESULTS Both EP-vBMD and Tb-vBMD could be measured in 210 levels of 96 patients. Severe cage subsidence was observed in 58 levels in 38 patients. Median (IQR) Tb-vBMD was 120.5 mg/cm3 (100.8-153.7) in the non-severe subsidence group and 117.9 mg/cm3 (90.6-149.5) in the severe subsidence group (p = 0.393), whereas EP-vBMD was significantly lower in the severe subsidence group than the non-severe subsidence group (non-severe subsidence 257.4 mg/cm3 (216.3-299.4), severe subsidence 233.5 mg/cm3 (193.4-273.3), p = 0.026). CONCLUSION We introduced a novel site-specific vBMD measurement for cage subsidence risk assessment. Our results showed that EP-vBMD was a reproducible measurement and appeared more predictive for severe cage subsidence after SA-LLIF than Tb-vBMD. These slides can be retrieved under Electronic Supplementary Material.

中文翻译：

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通过定量计算机体层摄影术测量的终板容积骨矿物质密度，作为独立的外侧腰椎融合术后严重笼下陷的一种新型预测性措施。

目的定量计算机断层扫描（QCT）是双X射线吸收法测量骨矿物质密度（BMD）的另一种成像方法。QCT的一个优点是它允许在一个很小的区域中进行特定位置的体积BMD（vBMD）测量。在这项研究中，我们利用特定部位的终板vBMD（EP-vBMD）作为独立的外侧腰椎椎体间融合术（SA-LLIF）患者严重笼下陷的潜在预测指标，并对EP-vBMD和小梁进行回顾性比较研究椎骨中的vBMD（Tb-vBMD）。方法回顾性分析2007年至2016年接受SA-LLIF治疗的患者。EP-vBMD定义为在笼接触面下方5 mm感兴趣区域中所包含的皮质骨和小梁骨中测量的上，下终板体积BMD的平均值。我们比较了具有严重笼下陷的椎间盘水平和没有严重下陷的椎间盘水平之间的Tb-vBMD和EP-vBMD。结果在96例患者的210个水平中均可测量到EP-vBMD和Tb-vBMD。在38例患者中，有58例患者出现了严重的笼子下陷。非严重沉降组中位数（IQR）Tb-vBMD为120.5 mg / cm3（100.8-153.7），严重沉降组中位数（IQR）Tb-vBMD为117.9 mg / cm3（90.6-149.5），而EP-vBMD为严重沉降组的体重显着低于非严重沉降组（非严重沉降257.4 mg / cm3（216.3-299.4），严重沉降233.5 mg / cm3（193.4-273.3），p = 0.026）。结论我们介绍了一种新颖的针对特定地点的vBMD测量方法，用于笼形沉陷风险评估。我们的结果表明，EP-vBMD是一种可重复的测量方法，与Tb-vBMD相比，SA-LLIF后出现严重的笼罩下陷更具预测性。这些幻灯片可以在电子补充材料下找到。