Comparison of standing, side bending and awake supine manual traction dynamic radiographs for predicting spinal flexibility with postoperative correction rate in adolescent idiopathic scoliosis

Background: The aim of the study was to compare awake supine manual traction radiograph with standing side bending radiograph in adolescent idiopathic scoliosis (AIS) patients and to analyze, which one among them is the best predictor of spinal flexibility index in varying degrees of AIS curves with minimal to severe Cobb angle. Materials and Methods: AIS patients, who underwent surgery during the period from 2015 to 2018, were retrospectively analyzed. Supine manual traction anteroposterior radiograph were taken with the patient in the supine position, with traction applied by a person with the head halter at the chin and counter traction applied with pelvic belt, leg straps. Patients were divided into three groups A, B, and C based on Cobb angle of the major structural curve. Patients with Cobb angles between 40° to 65°, 65° to 90°, and more than 90° were included in Groups A, B, and C, respectively. Flexibility indices obtained from both traction and bending radiographs were correlated with percent change in Cobb angle correction post-surgery. Statistical analysis was done to find Pearson correlation coefficient (r) between variables and results were tabulated. Results: There were 36, 16, and 16 patients in Group A, B, and C, respectively. The mean age of the cohort was 13.38 years. Group A had a positive correlation to traction radiographs (r = + 0.188, P = 0.455). Group B had a statistically significant positive correlation to bending radiographs (r = + 0.729, P = 0.04). A statistically significant positive correlation with traction radiographs (r = + 0.769, P = 0.016) was seen in Group C. Conclusion: Awake supine manual traction radiographs reveal better flexibility index in severe stiff (Cobb more than 90°) curves. In moderately stiffer curves (Cobb 65°–90°) standing side bending radiographs provide a better flexibility index than traction radiographs. Supine manual traction radiographs should always accompany bending radiographs in evaluating AIS patients, especially with severe stiff curves.