Clinical Outcomes and Complications of Corrective Fusion Surgery Down to L4, L5, and the Pelvis for Adult Scoliosis in Patients Younger than 50 Years

INTRODUCTION: Corrective fusion for adult scoliosis often requires fusion from the thoracic spine to the lower lumbar spine or pelvis. However, it is often difficult to determine the lowest instrumented vertebrae (LIV), especially in younger patients. The purpose of this study was to summarize the clinical outcomes and revision surgery rates after corrective fusion for adult scoliosis at different LIV levels in patients under 50 years of age. METHODS: We retrospectively analyzed 25 patients with adult scoliosis (mean age, 38 years; mean follow-up, 65 months) who underwent corrective fusion from the thoracic spine to L4, L5, or pelvis between 2010 and 2018. Preoperative and at least 2 years' postoperative radiographic parameters, patient-reported outcomes (Scoliosis Research Society-22r [SRS-22r]), mechanical complications, and revision surgery were investigated, and comparisons were made between two groups: the L4 and L5 (L) group (n=14) and the pelvic group (n=11). RESULTS: Both groups showed a significant improvement in the SRS-22r domains of Self-image and Subtotal postoperatively compared with the baseline (P<0.05). The incidence of rod fracture was significantly higher in the pelvic group (5 patients, 45%) than in the L group (0 patients, 0%) (P=0.001). In addition, revision surgery was performed five times in 4 patients (36%) in the pelvic group compared with 0 in the L group (P=0.068). CONCLUSIONS: In the L group, clinical outcomes improved in the medium term, with no patients requiring revision surgery. In the pelvic group, the rod fracture rate was higher, but the clinical outcomes improved.