Spine Center, Department of Orthopedic Surgery, Niigata Central Hospital, 1-18 Shinkocho, Chuo-ku, Niigata, Niigata 950-8556, Japan; Department of Orthopedic Surgery, Niigata City General Hospital, 463-7, Shumoku, Chuo-ku, Niigata, Niigata 950-1197, Japan.
Spine Center, Department of Orthopedic Surgery, Niigata Central Hospital, 1-18 Shinkocho, Chuo-ku, Niigata, Niigata 950-8556, Japan.
J Clin Neurosci. 2023 Jul;113:1-6. doi: 10.1016/j.jocn.2023.04.019. Epub 2023 Apr 29.
We investigated whether computed tomography (CT) Hounsfield unit (HU) values of the S1 screw trajectory can predict screw loosening after lumbosacral fixation. We analysed 102 patients (58 men and 44 women) who underwent L5-S1 interbody fusion between April 2018 and October 2019. We reviewed the characteristics of patients including body mass index, smoking, comorbidity with diabetes mellitus, and interbody fusion types. Bone mineral density (BMD) was obtained from the lumbar spine and total hip using dual-energy X-ray absorptiometry. Additionally, we reviewed the S1 screw lengths and diameters. HU values of both L1 vertebral bodies and bilateral S1 screw trajectories were measured on preoperative CT. At six months postoperatively, S1 screws on CT were assessed. Screws with a 1 mm or more radiolucent zone were defined as "loosening". Seventeen patients had loosened screws, and 85 patients did not. The patient characteristics did not significantly differ between the two groups. Both total hip BMD and L1 HU values were low in the loosening patient group (both p = 0.03). Of the 204 total S1 screws, 25 screws were loosened, and 179 screws were not. The screw length was short (p = 0.01), and the HU value of the S1 screw trajectory was low (p < 0.001) in the loosening screw group. Based on receiver operating characteristic analyses of these factors, the area under the curve of HU value of the S1 screw trajectory was the highest (0.79). Measuring the HU value of both the L1 vertebral body and S1 screw trajectory aids in predicting screw loosening.
我们研究了 CT 亨氏单位（HU）值能否预测腰骶固定后 S1 螺钉松动。我们分析了 2018 年 4 月至 2019 年 10 月期间接受 L5-S1 椎间融合术的 102 例患者（58 名男性和 44 名女性）。我们回顾了患者的特征，包括体重指数、吸烟、糖尿病合并症和椎间融合类型。骨密度（BMD）通过双能 X 射线吸收法从腰椎和全髋关节获得。此外，我们还回顾了 S1 螺钉的长度和直径。在术前 CT 上测量了 L1 椎体和双侧 S1 螺钉轨迹的 HU 值。术后 6 个月，对 S1 螺钉进行 CT 评估。螺钉有 1 毫米或更多的透光区定义为“松动”。17 例患者螺钉松动，85 例患者未松动。两组患者的特征无显著差异。松动患者组的总髋关节 BMD 和 L1 HU 值均较低（均 p=0.03）。在 204 个 S1 总螺钉中，有 25 个螺钉松动，179 个螺钉未松动。松动螺钉组的螺钉长度较短（p=0.01），S1 螺钉轨迹的 HU 值较低（p<0.001）。根据这些因素的接收者操作特征分析，S1 螺钉轨迹 HU 值的曲线下面积最高（0.79）。测量 L1 椎体和 S1 螺钉轨迹的 HU 值有助于预测螺钉松动。
