Impact of surgical correction of severe scoliotic spinal deformities on sagittal balance parameters in adolescents

BACKGROUND: Surgical correction of scoliotic spinal deformities involving long-segment spinal fusion inevitably leads to changes in sagittal balance parameters, which may affect treatment outcomes in patients with scoliosis. This issue has been addressed only sporadically in the scientific data and requires further investigation. AIM: This study aimed to analyze the impact of spinal deformity surgical correction on sagittal balance parameters in adolescents with severe thoracic idiopathic scoliosis in the early postoperative period. METHODS: The study included 38 patients who underwent surgery between 2021 and 2025, which consisted of discectomy–apophysectomy at the apex of the main scoliotic curve, intraoperative halo traction, and correction and stabilization of the deformity using a posterior multisegmental pedicle screw instrumentation in a single surgical session. The inclusion criteria were as follows: idiopathic scoliosis with a primary thoracic curve; age 12–17 years; availability of standing full-spine radiographs in two projections obtained before and after surgery; and main scoliotic curve with a Cobb angle of more than 80°. The non-inclusion criteria included: congenital spinal, spinal canal, or spinal cord abnormalities; systemic musculoskeletal disorders; lower limb orthopedic condition; previous surgery on the spine, pelvic ring, or chest; poor-quality radiographs precluding reliable sagittal balance assessment; and refusal to participate in the study. Radiographic examination was performed preoperatively and 10–14 days after surgery. The regional and global sagittal balance parameters and frontal plane deformity characteristics were assessed. RESULTS: Deviations in global sagittal balance parameters (SSA, TPA, and SVA) were observed preoperatively in 11 of 38 patients (28.9%). After surgery, such deviations were observed in 2 patients (5.3%). Insufficient correction of the kyphotic component of the deformity was identified as a significant risk factor for the persistence of anterior sagittal imbalance after surgery in patients with severe idiopathic scoliosis. CONCLUSION: Surgery using the described approach achieves optimal global and regional sagittal balance parameters in most adolescents with severe idiopathic scoliosis. However, in cases of extremely severe deformities (Cobb angle 120–130°), which are characterized by a pronounced kyphotic component, techniques enabling greater correction of thoracic kyphosis should be considered.