Objective: To evaluate sagittal and coronal alignment changes of the lumbar spine in lumbar disc herniation [LDH] patients.

Materials and Methods: A retrospective review was conducted measuring changes in sagittal and pelvic parameters as well as coronal plane deformity changes in sixty-two lumbar disc herniation patients who had been operated on at Ramathibodi Hospital including calculation of differences in changes of the sagittal alignment inpatients with and without coronal plane deformity.

Results: The median interquartile range of pelvic incidence, sacral slope, and pelvic tilt were 48.25+12.63, 30+10.75 and 17.5+11.63 degrees, respectively. The mean lumbar lordosis was 41+17.25 degrees. Coronal plain analysis found 16.39% of the patients had a significant coronal deformity (defined as a Cobb angle >10 degrees). In 70% of the patients, the deformity was on the curve side (convex side), the same side as the disc lesion, and 90% of the coronal deformities had minimal rotation (Nash & Moe grade 0 or 1). There were no statistically significant differences in sagittal parameters between groups with and without coronal plane deformity with the exception of lumbar inclination.

Conclusion: Lumbar disc herniation can exhibit changes in both sagittal and coronal alignment. Herniation probably decreases sacral slope and lumbar lordosis,but increases pelvic tilt. Coronal deformity was found in about 16% of patients,while most patients had minimal spinal rotation. There was no significant correlation between sagittal and coronal imbalance in the two groups of patients.

Keywords: Sagittal alignment, Coronal alignment, Lumbar disc herniation, Deformity