Spine Center, Mirae Hospital, Ulsan, Korea.
Clin Orthop Surg. 2010 Mar;2(1):8-12. doi: 10.4055/cios.2010.2.1.8. Epub 2010 Feb 4.
The lateral radiograph-based system described by Tsuyama is used widely to classify ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. However, OPLL is a complex 3-dimensional (3-D) lesion, not a simple and uniplanar one, which is often difficult to identify on a lateral radiograph. Furthermore, its reliability among spine surgeons has not been investigated. Given the popularity of a reconstructed computed tomography (CT), this study examined the inter- and intra-observer reliability of lateral radiograph-based OPLL classification using that modality.
Five spine surgeons independently reviewed the lateral radiograph, axial CT, 2-D (sagittal) and 3-D reconstructed CT images of 108 OPLL patients on 2 separate occasions. Based on these images, the reviewers classified each OPLL case according to the Tsuyama's system. The kappa values were used to assess the statistical reliability.
The inter- and intra-observer kappa values were only 0.51 and 0.67 for the lateral radiograph, even in combination with the axial CT images, 0.70 and 0.85 for 2-D CT images, and 0.76 and 0.86 for 3-D CT images, respectively. These kappa values showed a good-to-excellent range for the 2-D and 3-D reconstructed CT images while those of the lateral radiograph indicated a fair range. According to the OPLL types, the inter- and intra-observer reliability was low in the continuous type and high in the circumscribed type on the lateral radiograph. However, the low reliability of the continuous type on lateral radiograph was overcome somewhat using 2-D and 3-D reconstructed CT images.
The inter- and intra-observer kappa values were only 0.51 and 0.67 for the lateral radiograph, even in combination with the axial CT images, 0.70 and 0.85 for 2-D CT images, and 0.76 and 0.86 for 3-D CT images, respectively. These kappa values showed a good-to-excellent range for the 2-D and 3-D reconstructed CT images while those of the lateral radiograph indicated a fair range. According to the OPLL types, the inter- and intra-observer reliability was low in the continuous type and high in the circumscribed type on the lateral radiograph. However, the low reliability of the continuous type on lateral radiograph was overcome somewhat using 2-D and 3-D reconstructed CT images.
Tsuyama 描述的基于侧位 X 线片的系统被广泛用于对颈椎后纵韧带骨化症（OPLL）进行分类。然而，OPLL 是一种复杂的三维（3-D）病变，而不是简单的二维（2-D）病变，在侧位 X 线片上往往难以识别。此外，其在脊柱外科医生中的可靠性尚未得到研究。鉴于重建 CT（CT）的普及，本研究使用该方法检查了基于侧位 X 线片的 OPLL 分类的观察者内和观察者间可靠性。
5 名脊柱外科医生在 2 次不同的时间独立查看了 108 例 OPLL 患者的侧位 X 线片、轴位 CT、2-D（矢状位）和 3-D 重建 CT 图像。根据这些图像，每位审阅者均按照 Tsuyama 系统对每个 OPLL 病例进行分类。使用 Kappa 值评估统计可靠性。
即使与轴位 CT 图像相结合，侧位 X 线片的观察者内和观察者间 Kappa 值也仅为 0.51 和 0.67，2-D CT 图像的 Kappa 值为 0.70 和 0.85，3-D CT 图像的 Kappa 值为 0.76 和 0.86。这些 Kappa 值对于 2-D 和 3-D 重建 CT 图像显示出良好到极好的范围，而对于侧位 X 线片则显示出适度的范围。根据 OPLL 类型，在侧位 X 线片上，连续型的观察者内和观察者间可靠性较低，而局灶型的可靠性较高。然而，连续型在侧位 X 线片上的低可靠性在使用 2-D 和 3-D 重建 CT 图像时得到了一定程度的弥补。
即使与轴位 CT 图像相结合，侧位 X 线片的观察者内和观察者间 Kappa 值也仅为 0.51 和 0.67，2-D CT 图像的 Kappa 值为 0.70 和 0.85，3-D CT 图像的 Kappa 值为 0.76 和 0.86。这些 Kappa 值对于 2-D 和 3-D 重建 CT 图像显示出良好到极好的范围，而对于侧位 X 线片则显示出适度的范围。根据 OPLL 类型，在侧位 X 线片上，连续型的观察者内和观察者间可靠性较低，而局灶型的可靠性较高。然而，连续型在侧位 X 线片上的低可靠性在使用 2-D 和 3-D 重建 CT 图像时得到了一定程度的弥补。
