Department of Neurosurgery, Mie Chuo Medical Center, 2158-5 Myojin-cho, 514-1101, Hisai, Tsu, Mie, Japan.
Department of Neurosurgery, Mie University Graduate School of Medicine, 2-174 Edobashi, 514-8507, Tsu, Mie, Japan.
Clin Neuroradiol. 2022 Sep;32(3):717-724. doi: 10.1007/s00062-021-01132-z. Epub 2022 Jan 10.
A radiologic assessment method to measure position change of screw-rod constructs over time by superposing the 3‑dimensional images assists in quantitative evaluation of screw loosening. We investigated the association between position change and radiolucent zone that was commonly used for diagnosing screw loosening.
In this study 101 patients who underwent lumbar fusion were reviewed. Patient characteristics included age, sex, indications for surgery, number of fused levels, surgical procedures, and timing of follow-up computed tomography (CT, 1-5 months, 6-11 months, and ≥ 12 months). The Hounsfield unit values of L1 vertebra on preoperative CT were measured, and the radiolucent zone on each follow-up CT was evaluated. Using baseline CT on the day after surgery and follow-up CT, 3‑dimensional images of screw-rod constructs were generated and superposed. Position change was assessed by the median of the distances between the 3‑dimensional images at baseline and follow-up using the automated measurement method. Patient characteristics, the Hounsfield unit values of L1, and the amount of position change were categorized into the radiolucent zone presence and absence groups and compared.
The medians of position change were 0.281 mm and 0.136 mm in the radiolucent zone presence and absence groups, respectively (P < 0.001 by Mann-Whitney U-test). The area under the curve for position change in identifying radiolucent zone was 0.846; the cut-off value was 1.76 mm. In multivariable analysis, position change was independently associated with radiolucent zone (adjusted odds ratio per 0.1 mm, 2.80, 95% confidence interval 1.70-4.61).
Radiolucent zone was associated with position change of screw-rod constructs.
通过叠加三维图像来测量螺钉-棒结构随时间的位置变化的放射学评估方法有助于对螺钉松动进行定量评估。我们研究了位置变化与常用于诊断螺钉松动的透亮带之间的关系。
本研究回顾了 101 例接受腰椎融合术的患者。患者特征包括年龄、性别、手术指征、融合节段数、手术方式以及随访时间（术后 1-5 个月、6-11 个月和≥12 个月行 CT 检查）。术前 CT 测量 L1 椎体的 Hounsfield 单位值，并评估每次随访 CT 的透亮带。使用术后第 1 天的基线 CT 和随访 CT 生成并叠加螺钉-棒结构的三维图像。使用自动测量方法评估基线和随访三维图像之间距离的中位数来评估位置变化。根据透亮带的存在与否将患者特征、L1 的 Hounsfield 单位值和位置变化量进行分类并进行比较。
透亮带存在组和不存在组的位置变化中位数分别为 0.281 mm 和 0.136 mm（Mann-Whitney U 检验，P<0.001）。位置变化对识别透亮带的曲线下面积为 0.846；截断值为 1.76 mm。多变量分析显示，位置变化与透亮带独立相关（每 0.1 mm 的调整比值比为 2.80，95%置信区间为 1.70-4.61）。
透亮带与螺钉-棒结构的位置变化有关。
