Mid-term clinical outcomes of posterior spinal instrumentation surgery in thoracolumbar and lumbar curvatures of adolescent idiopathic scoliosis patients

Background: The aim of this study is to evaluate the mid-term surgical, clinical, and radiological outcomes of posterior spinal instrumentation (PSI) in patients diagnosed with adolescent idiopathic scoliosis (AIS) presenting thoracolumbar and lumbar curvatures. Methods: This retrospective study included 43 AIS patients who underwent posterior spinal fusion between 2020 and 2022 at two different centers. Patients with syndromic scoliosis or incomplete data were excluded. All procedures were performed by the same surgical team using a posterior approach under general anesthesia. A minimum of 10 and a maximum of 15 levels were instrumented from T2 to S1. In addition to standard instrumentation, vertebral column resection (VCR), pedicle subtraction osteotomy (PSO), and ponte osteotomies were applied in selected cases. Demographic data, operative parameters (duration, blood loss, transfusion), hospital stay, radiological outcomes (Cobb angle, T1 tilt, lowest instrumented vertebra [LIV] angle), pulmonary function test results (FVC, FEV1), and scoliosis research society 24-item questionnaire (SRS-24) were collected and analyzed. Results: The mean age of the patients was 14.83 ± 2.12 years, and the average follow-up period was 15 ± 7.74 months. The mean preoperative Cobb angle was 48.93°, which improved to 2.88° postoperatively. Postoperative improvements were also observed in T1 tilt and LIV angles. Pulmonary function tests revealed increased FVC and FEV1 values after surgery. The mean SRS-24 score was 96 ± 19, reflecting high patient satisfaction and functional recovery. Postoperative complications included cerebrospinal fluid leakage in three patients (treated successfully with epidural blood patch), pleural injury in one patient (repaired intraoperatively), and two cases of surgical site infection (managed with antibiotics, debridement, and hyperbaric oxygen therapy). No major neurological complications were recorded. Conclusions: Posterior spinal instrumentation is an effective and safe surgical technique for correcting spinal deformity and improving respiratory function in AIS patients with thoracolumbar and lumbar curves. The low complication rates and high SRS-24 scores observed in this study align with existing literature and highlight the reliability of PSI when performed with proper indication and planning. Early diagnosis and timely surgical intervention are crucial for achieving optimal outcomes in this patient population.