118. The incremental clinical benefit of adding layers of complexity to the planning and execution of adult spinal deformity corrective surgery

Abstract

BACKGROUND CONTEXT For surgical adult spinal deformity (ASD) patients, determining optimal restoration of alignment and spinal shape have been increasingly studied. Temporally, the SRS-Schwab classification system was the first severity categorization system. Next, the age-adjusted alignment was proposed, followed by Roussouly classification, and then a spinal proportionality score to minimize mechanical complications. These additional layers of complexity add to an already technically challenging and high risk case. What hasn't been determined is the incremental benefit of these. PURPOSE To assess the incremental benefits of adding ASD surgical corrective measures on patient-reported outcomes. STUDY DESIGN/SETTING Retrospective. PATIENT SAMPLE This study included 732 ASD patients. OUTCOME MEASURES Complications; health related quality of life (HRQL). METHODS ASD patients with baseline (BL) and 2-year postoperative (2Y) data included. Patients were classified by the four proposed corrective alignment measures: SRS-Schwab: PT, SVA and PI-LL(0, +, and ++); Age-adjusted: PT, PI-LL, and SVA-adjusted ideal; Roussouly type: ‘Match’ or ‘Mismatch,’ their theoretical type; spinal proportionality: sagittal disproportion score out of 13. Alignment improvement: SRS-Schwab 0 or decrease in severity, Age-adjusted ideal match, Roussouly theoretical Match, and decrease in proportion. To assess the incremental benefit of layers of complexity, patients were separated into 4 groups: the first layer (1st) solely improving in SRS-Schwab at 2Y, 2nd as Schwab improvement and matching Age-adjusted, 3rd as the two prior with matching of Roussouly, and 4th improvement in Schwab and proportionality, as well as matching both Age-adjusted ideals and Roussouly. Comparison was accomplished with means comparison tests and chi-squared analyses. RESULTS A total of 732 ASD patients (57.5yrs, 82.4%F, 27kg/m2) included. SRS-Schwab BL: PI-LL (++:32.9%), SVA (++: 23%), PT (++:24.6%). At 2 year, 54.9% improved in PT modifier, 71% SVA, 74.3% PI-LL. For Age-adjusted ideal, 28% met PT ideal, 18.8% PI-LL, and 31.3% SVA. By 2 years, 44.7% matched Roussouly types. At 2 years, 30.8% improved in spine proportion. According to layer of correction complexity groups: 640 (87.4%) met criteria for first, 517 (70.6%) 2nd, 176 (24%) 3rd, and 55 (7.5%) 4th. When comparing the incremental adding of the second layer, or age-adjusted ideals to Schwab improvement, complications and HRQLs were similar (p>0.05). Addition of Roussouly (third) had less mechanical complications and PJK (48.3%), and met MCID for PCS and SRS-Mental (p CONCLUSIONS Consideration of multiple complex realignment techniques, taking into account deformity severity, age, shape, and spinal proportion, may assist in optimizing patient-reported outcomes following spinal realignment surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.