Nassar Joseph E, Singh Manjot, McCrae Brian, Xu Andrew, Knebel Ashley, Farias Michael J, Cohen Eric M, Diebo Bassel G, Daniels Alan H
Department of Orthopedic Surgery, Warren Alpert Medical School of Brown University, Providence, Rhode Island.
J Bone Joint Surg Am. 2025 Apr 24;107(12):1352-1361. doi: 10.2106/JBJS.24.01118.
Sarcopenia increases postoperative complication and mortality rates in elderly patients. Although measurement of the psoas muscle area on computed tomography (CT) scans is traditionally used to diagnose sarcopenia, CT is not routine in orthopaedic practice and causes unnecessary radiation exposure. EOS, a low-dose full-body imaging modality, captures musculoskeletal structures in an upright position, offering an alternative for sarcopenia diagnosis.
Patients ≥18 years of age were included in this retrospective study if they had undergone non-contrast CT spine and EOS imaging between May 2022 and May 2024. Psoas muscle measurements at L3 and L4 were made using non-contrast CT scans, while thigh muscle measurements were obtained with EOS imaging. Inter- and intra-rater reliabilities were assessed using intraclass correlation coefficients (ICCs). Predicted probabilities for L4-psoas sarcopenia were determined through logistic regression, controlling for demographic covariates and validated with an 80% to 20% train-validate split. Sarcopenia cutoffs for anteroposterior (AP) thigh thickness and lateral (LAT) quadriceps thickness were determined with use of the Youden index.
Sarcopenia was identified in 23.1% of 134 patients (85 female and 49 male; 121 White, 7 Black, and 6 Hispanic) on the basis of L4-psoas muscle index thresholds. EOS and CT measurements showed excellent ICCs (≥0.90). Multivariable regressions identified AP thigh thickness and LAT quadriceps thickness as significant predictors of psoas area and L4-psoas sarcopenia. The area under the receiver operating characteristic curve for identifying L4-psoas sarcopenia was 0.85 for AP thigh thickness and 0.77 for LAT quadriceps thickness. Cutoffs were 12.47 cm (males) and 10.68 cm (females) for AP thigh thickness, and 3.23 cm (males) and 2.20 cm (females) for LAT quadriceps thickness. In the validation cohort of 27 patients, the AP thigh thickness model showed 0.94 sensitivity and 0.89 specificity, while the LAT quadriceps thickness model showed 0.70 sensitivity and 1.00 specificity. Applying these cutoffs to the entire data set showed that 66.7% of males and 75.0% of females with measurements below both cutoffs had sarcopenia.
EOS is a reliable alternative to CT for muscle mass assessment and sarcopenia diagnosis. EOS may be a valuable tool for assessing sarcopenia without a CT scan, as thigh muscle measurements via EOS correlate well with CT-derived psoas measurements. This imaging modality aids in early sarcopenia diagnosis, potentially enhancing preoperative planning and reducing radiation exposure, unnecessary costs, and resource utilization.
Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.
肌肉减少症会增加老年患者术后并发症和死亡率。虽然传统上通过计算机断层扫描（CT）测量腰大肌面积来诊断肌肉减少症，但CT在骨科实践中并非常规检查，且会导致不必要的辐射暴露。EOS是一种低剂量全身成像方式，能在直立位捕捉肌肉骨骼结构，为肌肉减少症的诊断提供了一种替代方法。
纳入2022年5月至2024年5月期间接受过非增强CT脊柱和EOS成像检查的18岁及以上患者进行这项回顾性研究。使用非增强CT扫描测量L3和L4水平的腰大肌，通过EOS成像获取大腿肌肉测量值。使用组内相关系数（ICC）评估评分者间和评分者内的可靠性。通过逻辑回归确定L4腰大肌肌肉减少症的预测概率，控制人口统计学协变量，并采用80%至20%的训练-验证分割进行验证。使用约登指数确定大腿前后径（AP）厚度和股四头肌外侧（LAT）厚度的肌肉减少症临界值。
根据L4腰大肌指数阈值，在134例患者（85例女性和49例男性；121例白人、7例黑人、6例西班牙裔）中，23.1%被诊断为肌肉减少症。EOS和CT测量显示出优异的ICC（≥0.90）。多变量回归确定大腿AP厚度和股四头肌LAT厚度是腰大肌面积和L4腰大肌肌肉减少症的重要预测因素。用于识别L4腰大肌肌肉减少症的受试者工作特征曲线下面积，大腿AP厚度为0.85，股四头肌LAT厚度为0.77。大腿AP厚度的临界值男性为12.47 cm，女性为10.68 cm；股四头肌LAT厚度的临界值男性为3.23 cm，女性为2.20 cm。在27例患者的验证队列中，大腿AP厚度模型的敏感性为0.94，特异性为0.89；股四头肌LAT厚度模型的敏感性为0.70，特异性为1.00。将这些临界值应用于整个数据集显示，两项测量值均低于临界值的男性中有66.7%、女性中有75.0%患有肌肉减少症。
EOS是用于肌肉量评估和肌肉减少症诊断的可靠替代CT检查手段。由于通过EOS测量的大腿肌肉与CT测量的腰大肌相关性良好，EOS可能是无需CT扫描即可评估肌肉减少症的有价值工具。这种成像方式有助于早期诊断肌肉减少症，可能改善术前规划，减少辐射暴露、不必要的费用和资源利用。
预后性III级。有关证据水平的完整描述，请参阅作者指南。
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