P102. Quantifying the Impact of Spinal Shape: Incorporating Roussouly Criteria into Novel Alignment Schemata Increases Probability of Optimal Radiographic Alignment in Adult Spinal Deformity Surgery

BACKGROUND CONTEXT Harmonizing the various ideal parameters defined in adult spinal deformity (ASD) surgery has recently come into prominence. GAP scoring, defined by relative pelvic incidence, relative lumbar lordosis, relative spinopelvic alignment, and the lordosis distribution index, was itself superseded by the SAAS system, which incorporated GAP and age-adjusted parameters to predict associations with proximal junctional kyphosis and postoperative outcomes. However, the incorporation of Roussouly typing into such schema has not been fully explored, and may be necessary in order to prevent postoperative complications and improve patients’ quality of life. PURPOSE To quantify spinal shape as defined by the Roussouly classification, in conjunction with existing Global Alignment and Proportion (GAP) parameters and the novel Sagittal Age-Adjusted Score (SAAS), to identify unique schema associated with optimal post-operative outcomes. STUDY DESIGN/SETTING Retrospective, single-center. PATIENT SAMPLE A total of 689 ASD patients. OUTCOME MEASURES Radiographics, complications, Health-Related Quality of Life (HRQLs) measures METHODS Surgical ASD patients (SVA≥5cm, PT≥25°, or TK ≥60°, >3 levels fused) ≥18 years old with available baseline (BL) radiographic data at baseline (BL) and 2-years (2Y) were isolated. Patients were grouped by “theoretical” Roussouly type (Type I: PI<45°, LL apex below L4; Type II: PI<45°, LL apex above L4, L4-L5 space; Type III: 45°3 levels fused) ≥18 years old with available baseline (BL) radiographic data at baseline (BL) and 2-years (2Y) were isolated. Patients were grouped by “theoretical” Roussouly type (Type I: PI<45°, LL apex below L4; Type II: PI<45°, LL apex above L4, L4-L5 space; Type III: 45°