Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital and West China School of Medicine, Sichuan University, Chengdu, 610041, PR China.
Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital and West China School of Medicine, Sichuan University, Chengdu, 610041, PR China.
Spine J. 2022 Jun;22(6):957-964. doi: 10.1016/j.spinee.2022.01.018. Epub 2022 Feb 3.
Cage subsidence is one of the most common complications following lumbar interbody fusion surgery. Low bone mineral density (BMD) is an important risk factor that contributes to cage subsidence. Hounsfield units (HU) obtained from clinical computed tomography (CT) scans provided a reliable method for determining regional BMD. The association between HU and cage subsidence following oblique lumbar interbody fusion (OLIF) remains unclear.
The objective of this study is to evaluate the association between vertebral HU value and cage subsidence following OLIF.
STUDY DESIGN/SETTING: A retrospective study.
Adults with degenerative spinal conditions underwent single-level OLIF at our institution from October 2017 and August 2020 OUTCOME MEASURES: Cage subsidence, disc height, vertebral body global HU value, upper and lower instrumented vertebrae HU value, endplate HU value, fusion rate.
This retrospective study was conducted on patients who underwent single-level OLIF at one institution between October 2017 and August 2020. Cage subsidence was measured using the CT scan postoperatively based on the cage protrusion through the vertebral endplates. The HU values were measured from preoperative CT according to previously reported methods.
A total of 70 patients with a mean follow-up of 15.4 months were included in the analysis. The subsidence rate was 25.7% (n=18/70). The average cage subsidence was 2.2 mm, with a range of 0-7.7 mm. No significant difference was found in age, sex, or body mass index (BMI) between the two groups. The mean global HU value of the lumbar vertebral body (L1-5) was 142.7±30.1 in nonsubsidence and 103.7±11.5 in subsidence (p=.004). The upper instrumented vertebrae (UIV) HU value was 141.4±29.7 in the nonsubsidence and 101.1±10.2 in subsidence, (p=.005). The lower instrumented vertebrae (LIV) HU value was 147.4±34.9 in nonsubsidence and 108.1±13.7 in subsidence, (p<.001). The AUC of the UIV HU value was 0.917 (95% CI: 0.853-0.981), and the most appropriate threshold of the HU value was 115 (sensitivity: 84.6%, specificity: 100%). The AUC of the LIV HU value was 0.893 (95%CI: 0.819-0.966), and the most appropriate threshold of the HU value was 125 (sensitivity: 76.9%, specificity: 100%). The mean upper endplate HU value was 235.4±50.9, and the mean lower endplate HU value was 193.4±40.3. No significant difference (upper endplate p=.314, lower endplate p=.189) was observed between the two groups.
Lower preoperative vertebral body HU values were associated with cage subsidence after single-level OLIF. However, the endplate HU values were not associated with cage subsidence. Preoperative HU measurement is useful in the prediction of the cage subsidence.
腰椎体间融合术后最常见的并发症之一是 cage 沉降。低骨密度（BMD）是导致 cage 沉降的重要危险因素。临床计算机断层扫描（CT）扫描获得的 Hounsfield 单位（HU）为确定局部 BMD 提供了可靠的方法。OLIF 后 HU 与 cage 沉降之间的关系尚不清楚。
本研究旨在评估 OLIF 后椎体 HU 值与 cage 沉降之间的关系。
研究设计/设置：回顾性研究。
2017 年 10 月至 2020 年 8 月在我院接受单节段 OLIF 的退行性脊柱疾病成人。
术后根据 cage 通过椎体面的突出测量 cage 沉降。根据之前报道的方法，使用术前 CT 测量 HU 值。
共纳入 70 例患者，平均随访 15.4 个月。沉降率为 25.7%（n=18/70）。平均 cage 沉降 2.2mm，范围 0-7.7mm。两组间年龄、性别、体重指数（BMI）无显著差异。腰椎体（L1-5）的平均整体 HU 值在非沉降组为 142.7±30.1，在沉降组为 103.7±11.5（p=.004）。上固定椎（UIV）HU 值在非沉降组为 141.4±29.7，在沉降组为 101.1±10.2（p=.005）。下固定椎（LIV）HU 值在非沉降组为 147.4±34.9，在沉降组为 108.1±13.7（p<.001）。UIV HU 值的 AUC 为 0.917（95%CI：0.853-0.981），最佳 HU 值阈值为 115（灵敏度：84.6%，特异性：100%）。LIV HU 值的 AUC 为 0.893（95%CI：0.819-0.966），最佳 HU 值阈值为 125（灵敏度：76.9%，特异性：100%）。上终板 HU 值平均值为 235.4±50.9，下终板 HU 值平均值为 193.4±40.3。两组间无显著差异（上终板 p=.314，下终板 p=.189）。
单节段 OLIF 后术前较低的椎体 HU 值与 cage 沉降有关。然而，终板 HU 值与 cage 沉降无关。术前 HU 测量有助于预测 cage 沉降。
