Reliability analysis for radiographic measures of lumbar lordosis in adult scoliosis: a case-control study comparing 6 methods

Abstract

Several methods are used to measure lumbar lordosis. In adult scoliosis patients, the measurement is difficult due to degenerative changes in the vertebral endplate as well as the coronal and sagittal deformity. We did the observational study with three examiners to determine the reliability of six methods for measuring the global lumbar lordosis in adult scoliosis patients. Ninety lateral lumbar radiographs were collected for the study. The radiographs were divided into normal (Cobb < 10A degrees), low-grade (Cobb 10A degrees-19A degrees), high-grade (Cobb a parts per thousand yen 20A degrees) group to determine the reliability of Cobb L1-S1, Cobb L1-L5, centroid, posterior tangent L1-S1, posterior tangent L1-L5 and TRALL method in adult scoliosis. The 90 lateral radiographs were measured twice by each of the three examiners using the six measurement methods. The data was analyzed to determine the inter- and intra-observer reliability. In general, for the six radiographic methods, the inter- and intra-class correlation coefficients (ICCs) were all a parts per thousand yen0.82. A comparison of the ICCs and 95% CI for the inter- and intra-observer reliability between the groups with varying degrees of scoliosis showed that, the reliability of the lordosis measurement decreased with increasing severity of scoliosis. In Cobb L1-S1, centroid and posterior tangent L1-S1 methods, the ICCs were relatively lower in the high-grade scoliosis group (a parts per thousand yen0.60). And, the mean absolute difference (MAD) in these methods was high in the high-grade scoliosis group (a parts per thousand currency sign7.17A degrees). However, in the Cobb L1-L5 and posterior tangent L1-L5 method, the ICCs were a parts per thousand yen0.86 in all groups. And, in the TRALL method, the ICCs were a parts per thousand yen0.76 in all groups. In addition, in the Cobb L1-L5 and posterior tangent L1-L5 method, the MAD was a parts per thousand currency sign3.63A degrees. And, in the TRALL method, the MAD was a parts per thousand currency sign3.84A degrees in all groups. We concluded that the Cobb L1-L5 and the posterior tangent L1-L5 methods are reliable methods for measuring the global lumbar lordosis in adult scoliosis. And the TRALL method is more reliable method than other methods which include the L5-S1 joint in lordosis measurement.