Are Both Preoperative Full‐Spine 3Dimensional Computed Tomography Scans and X‐Ray Films Necessary for Patients with Ankylosing Spondylitis Kyphosis?

OBJECTIVE: This study is aimed to investigate whether both pre‐operative full‐spine 3Dimensional computed tomography scan (3D CT) and X‐ray film were necessary for patients with severe ankylosing spondylitis (AS) kyphosis deformity. METHODS: The research objects were selected from the inpatients with AS in our hospital from 2017 to 2019. A total of 42 patients were included in the study. On both the synthesized 2Dimensional (2D) lateral radiograph and X‐ray film, the globe kyphosis (GK), the lumber lordosis (LL), the thoracolumbar kyphosis (TLK) and the thoracic kyphosis (TK) were measured. And the angle seventh thoracic vertebra (T7), the angle twelfth thoracic vertebra (T12) and the angle third lumber vertebra (L3) were also measured. Two researchers with professional medical education were randomly selected to perform the measurement method and record the measurement data. Two researchers independently completed, recorded, and evaluated the accuracy and consistency of the measurement data. This study used intraclass correlation coefficient (ICC) to analyze the synthesized 2D lateral radiograph and general X‐ray film of 42 subjects by two researchers, in order to evaluate the consistency of data measurement results between the examiners. Through the comparison of the above parameters that the GK, LL, TLK, TK, angle T7, angle T12 and angle L3, the evaluation was made both pre‐operative full‐spine 3D CT and X‐ray film were necessary for patients with severe AS kyphosis deformity. RESULTS: There was no significant difference between the GK, LL, TLK, TK, angle T7, angle T12, angle L3 on the synthesized 2D lateral radiograph and that on X‐ray film (P = 0.240, 0.324, 0.199, 0.095, 0.421, 0.087, 0.478). Agreement two researchers was excellent with ICC of the GK, LL, TLK, TK, angle T7, angle T12, angle L3 (0.977, 0.969, 0.986, 0.945, 0.947, 0.915, 0.857) on the synthesized 2D lateral radiograph. The Bland–Altman plot results that the measurement results of examiners are reliable and stable. CONCLUSION: By estimating the degree of spinal sagittal imbalance and measuring the Cobb angle, we can see that full‐length spine radiographs of the patients are unnecessary for patients with severe AS kyphosis deformity who will or have undergone preoperative spine 3D CT.