Zhang Rui-Fang, Fu Yu-Chuan, Lu Yi, Zhang Xiao-Xia, Hu Yu-Min, Zhou Yong-Jin, Tian Nai-Feng, He Jia-Wei, Yan Zhi-Han
Department of Radiology, Children's Hospital, Zhejiang University School of Medicine, 3333 Binsheng Rd, 310052 Hangzhou, China.
Department of Radiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuanxi Rd, 325027 Wenzhou, China.
Spine J. 2017 Feb;17(2):230-235. doi: 10.1016/j.spinee.2016.09.012. Epub 2016 Sep 21.
Accurately evaluating the extent of trunk imbalance in the coronal plane is significant for patients before and after treatment. We preliminarily practiced a new method, axis-line-angle technique (ALAT), for evaluating coronal trunk imbalance with excellent intra-observer and interobserver reliability. Radiologists and surgeons were encouraged to use this method in clinical practice. However, the optimal cutoff value of the ALAT for determination of the extent of coronal trunk imbalance has not been calculated up to now.
The purpose of this study was to identify the cutoff value of the ALAT that best predicts a positive measurement point to assess coronal balance or imbalance.
STUDY DESIGN/SETTING: A retrospective study at a university affiliated hospital was carried out.
A total of 130 patients with C7-central sacral vertical line (CSVL) >0 mm and aged 10-18 years were recruited in this study from September 2013 to December 2014.
Data were analyzed to determine the optimal cutoff value of the ALAT measurement.
The C7-CSVL and ALAT measurements were conducted respectively twice on plain film within a 2-week interval by two radiologists. The optimal cutoff value of the ALAT was analyzed via receiver operating characteristic (ROC) curve. Comparison variables were performed with chi-square test between the C7-CSVL and ALAT measurements for evaluating trunk imbalance. Kappa agreement coefficient method was used to test the intra-observer and interobserver agreement of C7-CSVL and ALAT.
The ROC curve area for the ALAT was 0.82 (95% confidence interval: 0.753-0.894, p<.001). The maximum Youden index was 0.51, and the corresponding cutoff point was 2.59°. No statistical difference was found between the C7-CSVL and ALAT measurements for evaluating trunk imbalance (p>.05). Intra-observer agreement values for the C7-CSVL measurements by observers 1 and 2 were 0.79 and 0.91 (p<.001), respectively, whereas intra-observer agreement values for the ALAT measurements were both 0.89 by observers 1 and 2 (p<.001). The interobserver agreement values for the first and second measurements with the C7-CSVL were 0.78 and 0.85 (p<.001), respectively, whereas the interobserver agreement values for the first and second measurements with the ALAT were 0.91 and 0.88 (p<.001), respectively.
The newly developed ALAT provided an acceptable optimal cutoff value for evaluating trunk imbalance in the coronal plane with a high level of intra-observer and interobserver agreement, which suggests that the ALAT is suitable for clinical use.
准确评估冠状面躯干失衡程度对患者治疗前后至关重要。我们初步实践了一种新方法——轴线角技术（ALAT），用于评估冠状面躯干失衡，其观察者内和观察者间可靠性良好。鼓励放射科医生和外科医生在临床实践中使用此方法。然而，截至目前，尚未计算出用于确定冠状面躯干失衡程度的ALAT最佳截断值。
本研究旨在确定能最佳预测阳性测量点以评估冠状面平衡或失衡的ALAT截断值。
研究设计/地点：在一家大学附属医院进行了一项回顾性研究。
2013年9月至2014年12月，本研究共招募了130例C7-中央骶骨垂直线（CSVL）>0mm且年龄在10 - 18岁的患者。
分析数据以确定ALAT测量的最佳截断值。
两名放射科医生在2周间隔内分别在平片上对C7-CSVL和ALAT进行两次测量。通过受试者工作特征（ROC）曲线分析ALAT的最佳截断值。使用卡方检验对C7-CSVL和ALAT测量进行比较变量分析以评估躯干失衡。采用Kappa一致性系数法检验C7-CSVL和ALAT的观察者内和观察者间一致性。
ALAT的ROC曲线面积为0.82（95%置信区间：0.753 - 0.894，p <.001）。最大约登指数为0.51，相应的截断点为2.59°。在评估躯干失衡方面，C7-CSVL和ALAT测量之间未发现统计学差异（p >.05）。观察者1和观察者2对C7-CSVL测量的观察者内一致性值分别为0.79和0.91（p <.001），而观察者1和观察者2对ALAT测量的观察者内一致性值均为0.89（p <.001）。第一次和第二次测量中C7-CSVL的观察者间一致性值分别为0.78和0.85（p <.001），而第一次和第二次测量中ALAT的观察者间一致性值分别为0.91和0.88（p <.001）。
新开发的ALAT为评估冠状面躯干失衡提供了可接受的最佳截断值，观察者内和观察者间一致性水平较高，这表明ALAT适用于临床应用。
