How coronal malalignment affects the surgical outcome in corrective spine surgery for adult symptomatic lumbar deformity

Purpose: The importance of coronal alignment is unclear, while the importance of sagittal alignment in the treatment of adult patients with spinal deformities is well described. This study sought to elucidate the impact of global coronal malalignment (GCMA) in surgically treated adult symptomatic lumbar deformity (ASLD) patients. Methods: A multicentre retrospective analysis of a prospective ASD database. GCMA was defined as GCA (C7PL-CSVL) ≥ 3 cm. GCMA is categorized based on the Obeid-Coronal Malalignment Classification (O-CM). Demographic, surgical, radiographic, HRQOL, and complication data were analysed. The risk for postoperative GCMA was analysed by univariate and multivariate analyses. Results: Of 230 surgically treated ASLD patients, 96 patients showed GCMA preoperatively and baseline GCA was correlated with the baseline SRS-22 pain domain score (r = − 30). Postoperatively, 62 patients (27%, O-CM type 1: 41[18%], type 2: 21[9%]) developed GCMA. The multivariate risk analysis indicated dementia (OR 20.1[1.2–304.4]), diabetes (OR 5.9[1.3–27.3]), and baseline O-CM type 2 (OR 2.1[1.3–3.4]) as independent risk factors for postoperative GCMA. The 2-year SRS-22 score was not different between the 2 groups, while 4 GCMA patients required revision surgery within 1 year after surgery due to coronal decompensation (GCMA+ vs. GCMA- function: 3.6 ± 0.6 vs. 3.7 ± 0.7, pain: 3.7 ± 0.8 vs. 3.8 ± 0.8, self-image: 3.6 ± 0.8 vs. 3.6 ± 0.8, mental health: 3.7 ± 0.8 vs. 3.8 ± 0.9, satisfaction: 3.9 ± 0.9 vs. 3.9 ± 0.8, total: 3.7 ± 0.7 vs. 3.7 ± 0.7). Additionally, the comparisons of 2-yr SRS-22 between GCMA ± showed no difference in any UIV and LIV level or O-CM type. Conclusions: In ASLD patients with corrective spine surgery, GCMA at 2 years did not affect HRQOL or major complications at any spinal fusion extent or O-CM type of malalignment, whereas GCA correlated with pain intensity before surgery. These findings may warrant further study of the impact of GCMA on HRQOL in the surgical treatment of ASLD patients.