Radiation-free measurement tools to evaluate sagittal parameters in AIS patients: a reliability and validity study

Abstract

Purpose: This study aimed to evaluate the intra-rater reliability and validity in comparison with the two-dimensional radiography (XR) of inclinometer (INCL) and rasterstereography (RAST) for assessing spinal sagittal angles of AIS patients. Methods: Fifty-one AIS patients (13.5 (2.0) years, girls = 32 (63%), Cobb angle = 23.0 (17.4)°) were included in this study. Three repeated measurements of thoracic kyphosis (TK) and lumbar lordosis (LL) were evaluated using the INCL and RAST by the same operator on the same day of the XR examination. Intraclass correlation coefficients (ICC) were used to evaluate the reliability of the INCL and RAST systems. Additionally, Pearson coefficients were computed between the XR and INCL systems and between the XR and RAST systems. Results: Reliability of each radiation-free system was excellent (ICC > 0.75 for INCL and RAST) for both the TK and LL parameters. The Pearson coefficients between each of the radiation-free systems and the XR were high to moderate for the TK (0.50 < RTK < 0.75 for INCL and RAST), high to moderate for the LL as measured with the RAST (0.50 < RLL < 0.75 for RAST) and low for the LL as measured with the INCL (RLL < 0.50 for INCL). Conclusion: This study demonstrated that for the RAST and INCL in AIS patients, there was (1) an excellent reliability for the TK and LL, (2) a high-to-moderate validity for measuring the TK and (3) a moderate and low validity for measuring the LL, respectively. These radiation-free systems could be used for the clinical follow-up of AIS patients for the evaluation of the TK. Graphical abstract: These slides can be retrieved under Electronic Supplementary Material.[Figure not available: see fulltext.]