Surgical rates and operative outcome analysis in thoracolumbar and lumbar major adult scoliosis: Application of the new Adult Deformity Classification

STUDY DESIGN. Multicenter prospective consecutive clinical series. OBJECTIVE. Investigate the interaction between the Adult Deformity Classification and treatment patterns, surgical strategies, surgery effectiveness, and complication rates. SUMMARY OF BACKGROUND DATA. An Adult Deformity Classification has been established that applies radiographic parameters of disability. Preliminary intraobserver and interobserver analysis reveals excellent reliability of the classification. Outcomes studies have not been reported to date. METHODS. A total of 784 adult patients with thoracolumbar or lumbar deformity underwent radiographic evaluation (full-length frontal/sagittal) as well as health assessment: Oswestry Disability Index, Scoliosis Research Society-22, and SF-12. Patients were subdivided by treatment and surgical strategies; 1 year (111 patients) and 2 year (45 patients) follow-up data were analyzed. Interaction between classification, treatment, surgical strategy, health assessment changes, and complications were analyzed. RESULTS. Classification modifiers (lordosis, subluxation, sagittal balance) were found to have significant variation (higher rates) in surgical care as the grade of the modifier increased. Classification differentiated patients by surgical approach and/or technique. Interaction between classification and baseline health assessment impacts both postoperative health scores and complication rates. CONCLUSION. This investigation appears to offer the first comprehensive analysis of classification, treatment, and outcomes in a large adult deformity patient group. Significant treatment patterns and outcomes are coming to light as is the impact of surgical strategy