Patients With Coronal Malalignment Undergoing Adult Spinal Deformity Surgery Does Coronal Alignment Change From Immediately Postoperative to 2-years?

Study Design:Retrospective cohort study. Objectives:The objectives were to: (1) characterize the changes in coronal vertical axis (CVA) after adult spinal deformity (ASD) surgery from immediate postoperative to 2-years postoperative, and (2) assess for predictors of CVA change from immediate postoperative to 2-years postoperative. Summary of Background Data:It is unknown whether coronal correction obtained immediately postoperative accurately reflects long-term coronal alignment. Materials and Methods:A retrospective, single-institution registry was queried for patients undergoing ASD surgery from 2015-2019, including patients undergoing >= 6-level fusions with preoperative coronal malalignment (CM), defined as CVA >= 3 cm. A clinically significant change in CVA was defined a priori as >= 1 cm. Radiographic variables were obtained preoperatively, immediately postoperative, and at 2-years postoperative. Results:Of 368 patients undergoing ASD surgery, 124 (33.7%) had preoperative CM, and 64 (17.0%) completed 2-years follow-up. Among 64 patients, mean age was 53.6 +/- 15.4 years. Preoperatively, absolute mean CVA was 5.4 +/- 3.1 cm, which improved to 2.3 +/- 2.0 cm (P<0.001) immediately postoperative and 2.2 +/- 1.6 cm (P<0.001) at 2-years. The mean change in CVA from preoperative to immediately postoperative was 2.2 +/- 1.9 cm (0.3-14.4). During the immediate postoperative to 2-years interval, 29/64 (45.3%) patients experienced a significant change of CVA by >= 1 cm, of which 22/29 (76%) improved by a mean of 1.7 cm and 7/29 (24%) worsened by a mean of 3.5 cm. No preoperative or surgical factors were associated with changed CVA from immediately postoperative to 2-years. Conclusion:Among 64 patients undergoing ASD surgery with preoperative CM, 45.3% experienced a significant (>= 1 cm) change in their CVA from immediately postoperative to 2-years postoperative. Of these 29 patients, 22/29 (76%) improved, whereas 7/29 (24%) worsened. Although no factors were associated with undergoing a change in CVA, this information is useful in understanding the evolution and spontaneous coronal alignment changes that take place after major ASD coronal plane correction.