Correlation Between Lordosis Distribution Index, Lordosis Tilt, and Occurrence of Proximal Junctional Kyphosis Following Surgery for Adult Degenerative Scoliosis

Purpose This study aimed to evaluate the effect of postoperative reciprocal progression of Lordosis tilt (LT), Lordosis distribution index (LDI) and occurrence of Proximal junctional kyphosis (PJK) following surgery for Degenerative lumbar scoliosis (DLS). Methods A total of 122 consecutive patients with ADS were treated with correction of deformity and followed up for a minimum of 2 years. Spinopelvic parameters were measured preoperatively, postoperatively, and at the latest follow-up. The Japanese Orthopaedic Association score, Oswestry Disability Index, and visual analog scale scores were measured at the latest follow-up. Associations between LT, LDI, and PJK were analyzed using receiver operating characteristic analyses. Results The prevalence of PJK in the present study was 24.6%. The outcomes of patients with PJK were significantly worse than those of patients without PJK. Postoperative reciprocal progression in LT and LDI with lumbar lordosis restorative surgery was observed. Preoperative risk factors for PJK were older age, larger LT, and larger Cobb angle of the curves. Postoperative risk factors for PJK included postoperative LT and postoperative Cobb angle of the curves, which were smaller than those preoperatively. We found a strong correlation between postoperative LT and Cobb angle of the curves resulting in PJK. Patients with LT < - 8 degrees were at a higher risk of PJK. Conclusions LT can be used to predict the occurrence of PJK in patients undergoing surgery for DLS. Appropriate postoperative LT is crucial for preventing the progression of PJK.