Please check your email for the verification action. You may continue to use the site and you are now logged in, but you will not be able to return to the site in future until you confirm your email address.
Purpose: To determine the reliability of six measurement techniques for lumbosacral kyphosis.
Method: Using custom computer software, four raters evaluated 60 standing lateral radiographs of the lumbosacral spine during two sessions at a one week interval. The sample size consisted of 20 normal, 20 low and 20 high grade spondylolisthetic subjects. Six parameters were included for analysis: Boxall’s slip angle; Dubousset’s lumbosacral angle (LSA); the Spinal Deformity Study Group’s (SDSG) LSA; dysplastic SDSG LSA; sagittal rotation (SR); kyphotic Cobb angle (k-Cobb). Intra- and inter- rater reliability for all parameters was assessed using intra-class correlation coefficients (ICC). Correlations between parameters and slip percentage were evaluated with Pearson coefficients.
Results: The intra-rater ICC’s for all the parameters ranged between 0.81 and 0.97 and the inter-rater ICC’s were between 0.74 and 0.98. All parameters except sagittal rotation showed a medium to large correlation with slip percentage. Dubousset’s LSA and the kyphotic Cobb angle showed the largest correlations (r=−0.78 and r=−0.50, respectively). Sagittal rotation was associated with the weakest correlation (r=−0.10). All other parameters had medium correlations with percent slip (r=0.31 to 0.43).
Conclusion: All measurement techniques provided substantial to almost perfect inter- and intra- rater reliability. Dubousset’s LSA showed the strongest correlation with slip grade. However, this parameter does not reflect the local dysplastic changes that occur in lower L5 and upper S1 endplates. A longitudinal study evaluating the best suited parameter for predicting the risk of progression and response to surgical treatment is warranted.