Correction of severe adult idiopathic scoliosis posteriorly with skipped pedicle screw instrumentation and rod augmentation

Background: Although it is challenging to correct severe adult idiopathic scoliosis (ADIS) deformities, optimal results can be achieved by multiple asymmetric Ponte osteotomies with lower surgical risks. Skipping the apical instrumentation and using multiple rods and connectors may further facilitate the procedure. We named this method as "modular correction technique" (MCT). Methods: Sixty-two patients with severe ADIS who were treated with MCT were recruited into this study, and retrospectively evaluated. Radiographic and functional outcomes as well as pulmonary functions were examined preoperatively and at last follow-up. Main radiologic parameters were related to Cobb angles, coronal, sagittal, and shoulder balance. Scoliosis Research Society-22 questionnaire and the Oswestry Disability Index were used to evaluate clinical outcomes. Results: Average age of the patients was 41.3 years (range: 23-65). Thirty-nine of the patients were female and 23 of them were male. Coronal Cobb angle of the main curve, shoulder balance, coronal, and sagittal balance significantly improved after the surgery. Forced vital capacity and forced expiratory volume in the first second were mildly improved after the surgery, however the improvement was not statistically significant. Postoperative clinical outcome scores improved significantly. Conclusion: MCT can be performed with low risk of complications and relatively low operation time and blood loss. It facilitates rod insertion and correction maneuvers. Radiologic, especially coronal balance, and functional outcomes can be improved with minimal morbidity while deterioration of pulmonary function is prevented. This technique is useful in severe but relatively flexible ADIS deformities.