Orosz Lindsay D, Schuler Kirsten A, Allen Brandon J, Lerebo Wondwossen T, Yamout Tarek, Roy Rita T, Schuler Thomas C, Good Christopher R, Haines Colin M, Jazini Ehsan
Department of Research, The National Spine Health Foundation, Reston, VA 20191, USA.
Department of Research, The National Spine Health Foundation, Reston, VA 20191, USA.
Spine J. 2025 Sep;25(9):1899-1909. doi: 10.1016/j.spinee.2025.03.028. Epub 2025 Mar 29.
Bone mineral density assessment is essential for surgical planning for most spine surgeries, but gold standard dual-energy X-ray absorptiometry (DXA) is affected by degeneration often resulting in falsely elevated scores. Studies of the opportunistic measurement of computed tomography (CT) Hounsfield units (HU) suggest lower CTHU values predict interbody cage subsidence, yet cutoff values vary and lack standardization.
This study aimed to determine if value CTHU<135 was associated with lumbar interbody cage subsidence and to compare the predictive performance of subsidence between CTHU and DXA.
STUDY DESIGN/SETTING: Single-center, multisurgeon, retrospective cohort study.
Adult, circumferential lumbar fusions ≤5 interbody levels with DXA, CTs, radiographs, and at least 1 year of follow up.
CTHU at L1, lowest DXA T-score, and postoperative change in disc space height (cage migration) on radiographs.
Lowest DXA T-scores overall and of the lumbar spine were recorded and categorized, and L1 CTHUs were measured. Interbody fusions were analyzed for subsidence ≥2 mm on radiographs by a validated, computer vision algorithmic approach. Analysis determined if an association existed between subsidence and CTHU<135 or DXA lowest T-score. Logistic regression analyzed the performance of predicting subsidence by each method.
The 127-patient cohort had 82.7% degenerative pathologies, 45.7% males, median age of 60 years, 2.4% osteoporosis on DXA, 44.1% CTHU<135, and 13.4% subsidence. CTHU<135 (p=.004) and age (p=.016) were significantly associated with subsidence, however DXA lowest T-score (p=.550) was not. The odds of subsidence were significant if CTHU<135 for crude and adjusted (OR=4.0, 95% CI 1.2-13.9, p=.029) comparisons. The odds of subsidence were not significant for DXA lowest T-score or DXA lowest T-score (OR=1.8, 95% CI 0.6-4.9, p=.284 and OR=1.1, 95% CI 0.3-4.1, p=.920, respectively).
CTHU<135 was associated with subsidence while DXA lowest T-score was not in this study of patients with degenerative pathologies. The odds of subsidence were 4.0 times higher for CTHU<135 after controlling for known risks, supporting this cutoff value. This study suggests that CTHU is a more reliable predictor of subsidence than DXA in this primarily degenerative population and is a useful tool for assessing bone quality at the region of interest when planning lumbar surgery.
骨密度评估对于大多数脊柱手术的手术规划至关重要，但金标准双能X线吸收法（DXA）会受到退变的影响，常常导致分数假性升高。对计算机断层扫描（CT）亨氏单位（HU）进行机会性测量的研究表明，较低的CT HU值预示着椎间融合器下沉，然而临界值各不相同且缺乏标准化。
本研究旨在确定CT HU<135是否与腰椎椎间融合器下沉相关，并比较CT HU和DXA对下沉的预测性能。
研究设计/地点：单中心、多外科医生的回顾性队列研究。
接受DXA、CT扫描、X线检查且至少随访1年的≤5个椎间节段的成人环形腰椎融合术患者。
L1节段的CT HU、最低DXA T值以及X线片上术后椎间隙高度的变化（融合器移位）。
记录并分类总体及腰椎的最低DXA T值，测量L1节段的CT HU。采用经过验证的计算机视觉算法对椎间融合术进行分析，以确定X线片上融合器下沉≥2 mm的情况。分析确定下沉与CT HU<135或DXA最低T值之间是否存在关联。逻辑回归分析每种方法预测下沉的性能。
127例患者队列中，82.7%有退行性病变，45.7%为男性，中位年龄60岁，DXA显示2.4%患有骨质疏松症，44.1%的CT HU<135，13.4%出现下沉。CT HU<135（p = 0.004）和年龄（p = 0.016）与下沉显著相关，然而DXA最低T值（p = 0.550）并非如此。对于CT HU<135的粗略和校正比较（比值比=4.0，95%可信区间1.2 - 13.9，p = 0.029），下沉的几率显著。DXA最低T值或DXA最低T值的下沉几率不显著（分别为比值比=1.8，95%可信区间0.6 - 4.9，p = 0.284和比值比=1.1，95%可信区间0.3 - 4.1，p = 0.920）。
在这项针对退行性病变患者的研究中，CT HU<135与下沉相关，而DXA最低T值并非如此。在控制已知风险后，CT HU<135时下沉的几率高出4.0倍，支持这一临界值。本研究表明，在这个主要为退行性病变的人群中CT HU比DXA是更可靠的下沉预测指标，并且在规划腰椎手术时是评估感兴趣区域骨质量的有用工具。
