Patterns of coronal and sagittal deformities in adolescent idiopathic scoliosis

Abstract

Introduction: To determine the association between the coronal deformity and sagittal malalignment in patients with adolescent idiopathic scoliosis (AIS), and their possible influence on patient-perceived quality of life. Methods: A retrospective cross-sectional study of 1054 patients (10-18 years old) with AIS was performed. The coronal Cobb’s angle curvature were measured on posteroanterior radiographs. Sagittal parameters including thoracic kyphosis (TK) and lumbar lordosis (LL), pelvic incidence (PI), PI-LL mismatch (PI-LL), pelvic tilt, and sacral slope (SS) were measured on lateral radiographs. Patients were separated into groups according to the location of coronal major curve and the number of coronal structural curves, respectively. The refined 22-item Scoliosis Research Society questionnaire (SRS-22r) was collected to examine patient-perceived quality of life. Sagittal values were compared between groups, and its association with SRS-22r scores. Results: Thoracic major curves have significantly less PI-LL mismatch (p=0.0019), smaller LL (p=0.0032), and increased loss of TK (p<0.001) compared with thoracolumbar or lumbar major curves. Multiple structural curves group had significantly larger PI (p=0.022), larger SS (p=0.041), less PI-LL mismatch (p=0.049), and more loss in TK (p=0.012) than the single curve group. There was no correlation between SRS-22r scores with sagittal parameters, while the magnitude of coronal curve was negatively correlated with function, appearance, and pain domains. Conclusion: Thoracic curves are associated with less pelvic malalignment but greater thoracic hypokyphosis than thoracolumbar/lumbar curves. Multiple structural curves exhibit less spinopelvic malalignment than single curves. Coronal deformities have greater influence on quality of life outcomes compared with the sagittal parameter.