Sagittal malalignment has a significant association with postoperative leg pain in adult spinal deformity patients

To evaluate the association between spinopelvic sagittal parameters and leg pain in patients with adult spinal deformity (ASD) after adjusting for demographic and surgical variables. A multicenter prospective ASD database (European Spine Study Group) was retrospectively reviewed. The characteristics (age, sex, body mass index, comorbidity, history of spine surgery, and radiographical coronal and sagittal parameters) of patients with preoperative and 6-month postoperative leg pain (PostLP; numerical rating scale score a parts per thousand yen5) were analyzed using univariate and multivariate analyses. In this study, 204 patients (164 women and 40 men; mean age 53.1 years) were included. Fifty-three percent of the patients had preoperative leg pain (PreLP). The patients with PreLP had significantly worse sagittal parameters and less coronal Cobb angle than those with less leg pain; however, this association disappeared after adjustment for covariates. The PreLP of the ASD patients was successfully treated surgically in most cases; however, 24 % of the patients still had unexpected residual leg pain. Postoperative sagittal malalignment (sagittal vertical axis a parts per thousand yen40 mm, T1 sagittal tilt a parts per thousand yen0A degrees, pelvic tilt a parts per thousand yen30A degrees) was a significant risk factor of PostLP even after adjusting for covariates. Leg pain in patients with ASD was significantly associated with sagittal malalignment especially after surgical treatments. As these patients lose flexibility in the fused spinal segment, they can only depend on the remaining compensatory mechanisms below the pelvis (e.g., the hips and knees) to maintain a balanced posture. This may lead to a predisposition of these patients to postoperative leg symptoms related to spinal sagittal malalignment.