Effect of Coronal Scoliotic Curvature on Sagittal Spinal Shape Analysis of Parameters in Mature Adolescent Scoliosis Patients

Abstract

Study Design: A radiographic analysis with scoliosis patients. Objectives: To analyze correlations between sagittal spinal alignment and coronal scoliotic curvature. Summary of Background Data: Sagittal spinal alignment and scoliosis may have a significant relationship, and schematic analysis is needed. Methods: The study group was comprised of 163 patients with adolescent idiopathic scoliosis. Subjects underwent anteroposterior and lateral radiographs of the whole spine including hip joints. The radiographic parameters used were magnitude, location and direction of curve, thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, sagittal balance, sacral slope, and pelvic angle. Subjects were classified into 4 groups according to the severity of coronal curvature: Cobb angle <= 20 degrees, Cobb angle 21-40 degrees, Cobb angle 41-60 degrees, and Cobb angle >60 degrees. In addition, subjects were divided into 4 subgroups according to Roussouly's classification (types 1-4) of sagittal spinal shape. Schematic analysis was performed to determine the relationship between coronal and sagittal parameters. Results: Analysis of parameters with severity of coronal curvature, thoracic kyphosis, and sacral slope were significantly higher in high-grade scoliosis (P < 0.05). However, the pelvic angle was higher in low-grade scoliosis, and sagittal balance showed a significantly higher positive value in low-grade scoliosis (P < 0.05). In the analysis of sagittal spinal shapes, Roussouly groups 3 and 4 showed more severe scoliosis with higher lumbar lordosis and thoracic kyphosis (P < 0.05). In addition, Roussouly group 1 demonstrated a significantly higher incidence of low-grade scoliosis, whereas groups 3 and 4 had a higher incidence of high-degree scoliosis by cross-relation analysis (P < 0.05). Conclusions: A significant relationship exists between sagittal spinal shape and coronal curvature in scoliosis. Understanding the biplanar shapes of scoliosis may be helpful to the surgeons.