Department of Spine Surgery, the Second Affiliated Hospital of Dalian Medical University, Dalian, 116023, China.
Department of Orthopedics, Mianyang Central Hospital, Mianyang, 621000, China.
BMC Musculoskelet Disord. 2022 Feb 22;23(1):168. doi: 10.1186/s12891-022-05122-1.
Percutaneous pedicle screw fixation (PPSF) is the primary approach for single-segment thoracolumbar burst fractures (TLBF). The healing angle at the thoracolumbar junction is one of the most significant criteria for evaluating the efficacy of PPSF. Therefore, the purpose of this study was to analyze the predictors associated with the poor postoperative alignment of the thoracolumbar region from routine variables using a support vector machine (SVM) model.
We retrospectively analyzed patients with TLBF operated at our academic institute between March 1, 2014 and December 31, 2019. Stepwise logistic regression analysis was performed to assess potential statistical differences between all clinical and radiological variables and the adverse events. Based on multivariate logistic results, a series of independent risk factors were fed into the SVM model. Meanwhile, the feature importance of radiologic outcome for each parameter was explored. The predictive performance of the SVM classifier was evaluated using the area under the receiver operating characteristic curve (AUC), accuracy (ACC) and confusion matrices with 10-fold cross-validation, respectively.
In the recruited 150 TLBFs, unfavorable radiological outcomes were observed in 53 patients (35.33%). The relationship between osteoporosis (p = 0.036), preoperative Cobb angle (p = 0.001), immediate postoperative Cobb angle (p = 0.029), surgically corrected Cobb angle (p = 0.001), intervertebral disc injury (Score 2 p = 0.001, Score 3 p = 0.001), interpedicular distance (IPD) (p = 0.001), vertebral body compression rate (VBCR) (p = 0.010) and adverse events was confirmed by univariate regression. Thereafter, independent risk factors including preoperative Cobb angle, the disc status and IPD and independent protective factors surgical correction angle were identified by multivariable logistic regression. The established SVM classifier demonstrated favorable predictive performance with the best AUC = 0.93, average AUC = 0.88, and average ACC = 0.87. The variables associated with radiological outcomes, in order of correlation strength, were intervertebral disc injury (42%), surgically corrected Cobb angle (25%), preoperative Cobb angle (18%), and IPD (15%). The confusion matrix reveals the classification results of the discriminant analysis.
Critical radiographic indicators and surgical purposes were confirmed to be associated with an unfavorable radiographic outcome of TLBF. This SVM model demonstrated good predictive ability for endpoints in terms of adverse events in patients after PPSF surgery.
经皮椎弓根螺钉固定术（PPSF）是治疗单节段胸腰椎爆裂性骨折（TLBF）的主要方法。胸腰椎交界处的愈合角度是评估 PPSF 疗效的最重要标准之一。因此，本研究旨在使用支持向量机（SVM）模型，从常规变量分析与胸腰椎区域术后不良对线相关的预测因素。
我们回顾性分析了 2014 年 3 月 1 日至 2019 年 12 月 31 日在我院接受治疗的 TLBF 患者。采用逐步逻辑回归分析评估所有临床和影像学变量与不良事件之间的潜在统计学差异。基于多变量逻辑结果，将一系列独立风险因素输入 SVM 模型。同时，探索了每个参数对放射学结果的重要性。使用接收器操作特征曲线（AUC）下面积、准确性（ACC）和 10 倍交叉验证的混淆矩阵分别评估 SVM 分类器的预测性能。
在纳入的 150 例 TLBF 中，53 例（35.33%）观察到影像学结果不良。骨质疏松症（p=0.036）、术前 Cobb 角（p=0.001）、即刻术后 Cobb 角（p=0.029）、手术矫正 Cobb 角（p=0.001）、椎间盘损伤（评分 2 p=0.001，评分 3 p=0.001）、椎弓根间距（IPD）（p=0.001）、椎体压缩率（VBCR）（p=0.010）与不良事件之间的关系通过单变量回归得到确认。此后，通过多变量逻辑回归确定了包括术前 Cobb 角、椎间盘状态和 IPD 以及独立保护因素手术矫正角度在内的独立危险因素。所建立的 SVM 分类器表现出良好的预测性能，最佳 AUC=0.93、平均 AUC=0.88 和平均 ACC=0.87。与放射学结果相关的变量按相关性强度依次为椎间盘损伤（42%）、手术矫正 Cobb 角（25%）、术前 Cobb 角（18%）和 IPD（15%）。混淆矩阵显示了判别分析的分类结果。
证实了关键影像学指标和手术目的与 TLBF 的不良影像学结果相关。该 SVM 模型对 PPSF 手术后患者不良事件的终点具有良好的预测能力。
