Stokes Ian A F, Aronsson David D
Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, VT 05405-0084, USA.
Spine (Phila Pa 1976). 2006 Mar 15;31(6):665-70. doi: 10.1097/01.brs.0000203708.49972.ab.
Interobserver and intraobserver reliability study of improved method to evaluate radiographs of patients with scoliosis.
To determine the reliability of a computer-assisted measurement protocol for evaluating Cobb angle and King et al classification.
Evaluation of scoliosis radiographs is inherently unreliable because of technical and human judgmental errors. Objective, computer-assisted evaluation tools may improve reliability.
Posteroanterior preoperative radiographic images of 27 patients with adolescent idiopathic scoliosis were each displayed on a computer screen. They were marked 3 times in random sequence by each of 5 evaluators (observers) who marked 70 standardized points on the vertebrae and sacrum in each radiograph. A computer program (Spine 2002;27:2801-5) that identified curves, calculated Cobb angles, and generated the King et al classification automatically analyzed coordinates of these points. The interobserver and intraobserver variability of the Cobb angle and King et al classification evaluations were quantified and compared with values obtained by unassisted observers.
Average Cobb angle intraobserver standard deviation was 2.0 degrees for both the thoracic and lumbar curves (range 0.1 to 8.3 degrees for different curves). Interobserver reliability was 2.5 degrees for thoracic curves and 2.6 degrees for lumbar curves. Among the 5 observers, there was an inverse relationship between repeatability and time spent marking images, and no correlation with image quality or curve magnitude. Kappa values for the variability of the King et al classification averaged 0.85 (intraobserver).
Variability of Cobb measurements compares favorably with previously published series. The classification was more reliable than achieved by unassisted observers evaluating the same radiographs. The same principles may be applicable to other radiographic measurement and evaluation procedures.
对评估脊柱侧弯患者X线片的改良方法进行观察者间和观察者内可靠性研究。
确定一种用于评估Cobb角和King等分类法的计算机辅助测量方案的可靠性。
由于技术和人为判断误差，脊柱侧弯X线片的评估本质上是不可靠的。客观的计算机辅助评估工具可能会提高可靠性。
27例青少年特发性脊柱侧弯患者的术前正位X线片分别显示在计算机屏幕上。由5名评估者（观察者）以随机顺序对每张X线片标记3次，每位评估者在每张X线片的椎骨和骶骨上标记70个标准化点。一个能识别曲线、计算Cobb角并生成King等分类法的计算机程序（Spine 2002;27:2801 - 5）自动分析这些点的坐标。对Cobb角和King等分类法评估的观察者间和观察者内变异性进行量化，并与未借助辅助工具的观察者获得的值进行比较。
胸段和腰段曲线的观察者内平均Cobb角标准差均为2.0度（不同曲线范围为0.1至8.3度）。胸段曲线的观察者间可靠性为2.5度，腰段曲线为2.6度。在5名观察者中，重复性与标记图像所花费的时间呈负相关，与图像质量或曲线大小无关。King等分类法变异性的Kappa值平均为0.85（观察者内）。
Cobb测量的变异性与先前发表的系列研究结果相比具有优势。该分类法比未借助辅助工具的观察者评估相同X线片时更可靠。相同的原则可能适用于其他X线测量和评估程序。
