Objective To explore the differences in sagittal balance parameters between normal adolescents and adolescent idiopathic scoliosis, and to analyze the influencing factors of the disease. Methods A total of 242 full-spine sagittal X-ray images of adolescents were collected from three different tertiary hospitals. After screening, 100 images with complete imaging data were included in the study, comprising 50 healthy adolescents and 50 patients with adolescent idiopathic scoliosis (AIS). The imaging data were imported into Mimics 21.0 for the measurement of sagittal morphological parameters, including cervical Cobb Angle (CCA), Thoracic Kyphosis (TK), Lumbar Lordosis (LL), Thoracolumbar Kyphosis (TLK), Sagittal Vertical Axis (SVA), Spinal Tilt (ST), Spinosacral Angle (SSA), Spinopelvic Angle (SPA), T1 Spinopelvic Inclination (T1-SPI), T9 Spinopelvic Inclination (T9-SPI), T1 Pelvic Angle (TPA), Lumbar Pelvic Angle (LPA), Sacral Slope (SS), Pelvic Incidence (PI), and Pelvic Tilt (PT). Differences in these parameters were compared between healthy adolescents and AIS patients, as well as between male and female AIS patients. Correlations among parameters were also analyzed. Binary logistic regression analysis was performed to investigate the association between sagittal morphological parameters and the presence of AIS. Results Comparing the sagittal parameters between healthy adolescents and AIS patients showed statistically significant differences in TK, LL, PT, PI, SVA, SSA, SPA, and T9-SPI (Z=-3.712, P=0.000; t=16.648, P=0.000; Z=-2.203, P=0.028; Z= -2.147, P=0.032; Z=-3.812, P=0.000; Z=-3.381, P=0.001; Z=-3.723, P=0.000; Z=-3.550, P=0.000), while the remaining parameters showed no statistical significance (P>0.05). Comparing the gender differences within AIS patients, TK, LL, SS, SVA, ST, SPA, and T9-SPI showed statistically significant differences (Z=-2.367, P=0.018; t=6.317, P=0.015; t=6.480, P=0.014; Z=-2.319, P=0.020; Z=-2.377, P=0.017; Z=-2.843, P=0.004; Z=-2.464, P=0.014), while the remaining parameters showed no statistical significance (P>0.05). In AIS patients, the sagittal parameters showed that TK was weakly positively correlated with LL (r=0.282, P=0.047), significantly positively correlated with SVA (r=0.641, P=0.000), and weakly negatively correlated with TLK (r=-0.326, P=0.021). LL was significantly positively correlated with SS (r=0.772, P=0.000), moderately positively correlated with PI (r=0.435, P=0.002), and weakly positively correlated with SPA (r=0.324, P=0.022). PT was moderately positively correlated with PI (r=0.508, P=0.000). SS was moderately positively correlated with PI (r=0.548, P=0.000) and weakly positively correlated with SPA (r=0.289, P=0.042). SVA was weakly positively correlated with SSA (r=0.313, P=0.027) and weakly negatively correlated with TLK and T9-SPI (r=-0.324, P=0.022; r=-0.299, P=0.035). ST was significantly positively correlated with SPA (r=0.744, P=0.000). LPA was moderately positively correlated with TPA (r=0.5, P=0.000) and weakly negatively correlated with T9-SPI (r=-0.33, P=0.019). Binary logistic regression analysis revealed that there were statistically significant in TK, LL, SSA, SPA, and T9-SPI (P=0.007; P=0.025; P=0.005; P=0.012; P=0.018), while the remaining parameters showed no statistical significance (P>0.05). Conclusions In patients with AIS, TK, LL, SSA, and SPA were significantly increased, and T9-SPI was significantly decreased, indicating that AIS may lead to an increase in the overall inclination of the spine, accompanied by changes in the segmental curvature of the vertebral body and pelvic morphology. Therefore, the changes of the above parameters should be focused on in the preoperative evaluation, so as to fully grasp the overall balance of the spine and pelvis, and provide a reference for the formulation of individualized treatment plans.
Key words
Adolescent idiopathic scoliosis /
Sagittal position /
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Spine-pelvic parameters /
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Correlation analysis /
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Logistic regression analysis
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