191. Establishing a threshold of impairment to define coronal malalignment in adult spinal deformity patients

BACKGROUND CONTEXT No radiographic alignment threshold defines preop CM in ASD patients based on disability. PURPOSE An optimal threshold exists that defines CM based on patient-reported outcomes (PROs) in ASD patients. STUDY DESIGN/SETTING Cross-sectional. PATIENT SAMPLE This study included 368 adult deformity patients. OUTCOME MEASURES Patient-reported outcomes (ODI and SRS22r) and postoperative coronal and sagittal alignment METHODS A single-institution registry was searched for all patients undergoing ASD surgery with ≥6 level fusions. Coronal vertical axis (CVA) & sagittal vertical axis (SVA) were collected. PROs were preop ODI/SRS-22r scores. First, CVA & SVA thresholds were derived to accurately differentiate patients with ODI>40 & SRS-pain+function scores RESULTS A total of 368 patients underwent ASD surgery with a mean CVA of 3.1±4.1cm. Part 1: thresholds to distinguish patients with ODI>40 and SRS-pain/fx CONCLUSIONS Alignment thresholds that accurately distinguished ASD patients with severe pain and disability preoperatively were 3cm for CVA and 5cm for SVA. Preop CM was significantly associated with worse ODI, SRS-22r total/function/image scores. CCSM lead to more disability than SM alone. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.