Sagittal Spinopelvic Alignment in the Standing and Prone Positions of Patients with Old Traumatic Thoracolumbar Kyphosis: Relationship with Immediately Postoperative Parameters.

-OBJECTIVE: The aim of this study was to investigate the changes in spine-pelvis sagittal parameters from the standing position to the prone position and to study the relationship between sagittal parameters and immediately postoperative parameters. -METHODS: Thirty-six patients with old traumatic spinal fracture combined with kyphosis were enrolled. The pre-operative standing position, prone position, and post-operative sagittal parameters of the spine and pelvis, including the local kyphosis Cobb angle (LKCA), thoracic kyphosis angle (TKA), lumbar lordosis angle (LLA), sacral slope (SS), pelvic tilt (PT), pelvic incidence minus lumbar lordosis angle (PI-LLA), and sagittal vertebral axis (SVA), were measured. The data of kyphotic flexibility and correction rate werecollected and analyzed. The parame-ters of the preoperative standing position, prone position and postoperative sagittal position were analyzed statis-tically. Correlation analysis and regression analysis of the preoperative standing and prone sagittal parameters and postoperative parameters were conducted. -RESULTS: There were significant differences in the preoperative standing position, prone position, and post-operative LKCA and TK. Correlation analysis showed that preoperative sagittal parameters of the standing position and prone position were all correlated with postoperative homogeneity. Flexibility was not related to the correction rate. Regression analysis showed preoperative standing, prone LKCA, and TK were linear with postoperative standing. -CONCLUSIONS: The LKCA and TK of old traumatic kyphosis obviously changed from the standing position to the prone position, which were linear with postoperative LKCA and TK and can be used to predict postoperative sagittal parameters. This change should be taken into ac-count in the surgical strategy.