STUDY DESIGN: A retrospective correlation study. OBJECTIVE: To identify radiographically if there is a correlation of the sagittal thoracolumbar alignment to the axial vertebral rotation and coronal scoliotic curvature in thoracolumbar/lumbar (TL/L) adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: The consistent positive correlation between coronal angulations and axial rotation has been defined as a typical feature of AIS. However, the correlation of sagittal alignment transformation to axial and/or coronal deformity has not been definitely described, especially for primary TL/L AIS. METHODS: On standard anteroposterior and lateral radiographs of 43 patients with TL/L AIS, coronal and sagittal parameters including primary TL/L and compensatory thoracic curve, thoracic kyphosis, thoracolumbar junctional sagittal curve (TLJS), and lumbar lordosis, were evaluated using the Cobb method. Apical vertebral rotation (AVR) was evaluated using the Perdriolle torsionmeter. The correlation was investigated between all parameters. After the patients were divided into 2 subgroups according to the TLJS curvature, the average AVR and coronal TL/L Cobb were compared between the 2 groups. RESULTS: The average TLJS Cobb was 4.5° ± 8.8° (range, -12.5°-24.3°) with 28 cases (65.1% of all cases) in TLJS+ (kyphosis) group and 15 cases in TLJS- (lordosis) group. Significant correlations were observed between AVR and coronal TL/L curvature (P < 0.001), and between AVR and sagittal TLJS Cobb angle (P < 0.001). These correlations still existed when the partial correlation analysis was conducted. The correlation between sagittal TLJS and coronal TL/L curvature became nonsignificant (P = 0.405) when the partial correlation analysis was conducted with AVR as control variable. Besides, a significant difference of 7.0° was observed in average AVR between TLJS+ and TLJS- subgroups (P < 0.001). CONCLUSION: From the standard anteroposterior and lateral radiographs, an increased kyphosis of the thoracolumbar junction was observed in TL/L AIS, and it was demonstrated to be positively correlated to more axial vertebral rotation of the scoliotic spine.
STUDY DESIGN: A retrospective correlation study. OBJECTIVE: To identify radiographically if there is a correlation of the sagittal thoracolumbar alignment to the axial vertebral rotation and coronal scoliotic curvature in thoracolumbar/lumbar (TL/L) adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: The consistent positive correlation between coronal angulations and axial rotation has been defined as a typical feature of AIS. However, the correlation of sagittal alignment transformation to axial and/or coronal deformity has not been definitely described, especially for primary TL/L AIS. METHODS: On standard anteroposterior and lateral radiographs of 43 patients with TL/L AIS, coronal and sagittal parameters including primary TL/L and compensatory thoracic curve, thoracic kyphosis, thoracolumbar junctional sagittal curve (TLJS), and lumbar lordosis, were evaluated using the Cobb method. Apical vertebral rotation (AVR) was evaluated using the Perdriolle torsionmeter. The correlation was investigated between all parameters. After the patients were divided into 2 subgroups according to the TLJS curvature, the average AVR and coronal TL/L Cobb were compared between the 2 groups. RESULTS: The average TLJS Cobb was 4.5° ± 8.8° (range, -12.5°-24.3°) with 28 cases (65.1% of all cases) in TLJS+ (kyphosis) group and 15 cases in TLJS- (lordosis) group. Significant correlations were observed between AVR and coronal TL/L curvature (P < 0.001), and between AVR and sagittal TLJS Cobb angle (P < 0.001). These correlations still existed when the partial correlation analysis was conducted. The correlation between sagittal TLJS and coronal TL/L curvature became nonsignificant (P = 0.405) when the partial correlation analysis was conducted with AVR as control variable. Besides, a significant difference of 7.0° was observed in average AVR between TLJS+ and TLJS- subgroups (P < 0.001). CONCLUSION: From the standard anteroposterior and lateral radiographs, an increased kyphosis of the thoracolumbar junction was observed in TL/L AIS, and it was demonstrated to be positively correlated to more axial vertebral rotation of the scoliotic spine.