P90. Evaluation of the odontoid-coronal vertical axis line in coronal alignment in a symptomatic cohort

BACKGROUND CONTEXT The coronal alignment from the skull is understudied in adult spinal deformity (ASD) surgery. Previous literature on the odontoid-coronal vertical axis (OD-CVA) in an asymptomatic volunteer cohort showed its correlation with other radiographic parameters such as C7-CVA and thoracolumbar cobb angle. However, the correlation of OD-CVA with other radiographic parameters, surgical variables, patient-reported outcomes (PROs), and clinical outcomes in a symptomatic cohort is unknown. PURPOSE This project assesses how OD-CVA correlates with radiographic parameters and outcomes in a symptomatic cohort. STUDY DESIGN/SETTING A retrospective cohort of patients from multiple surgeons at a single institution. METHODS ASD patients with ≥6 fused levels were included in the symptomatic cohort for analysis. OD-CVA was analyzed alongside parameters, including C7-CVA, maximum coronal cobb angle (Max Cobb), lumbosacral fractional curve (LSFC), SVA, pelvic obliquity (PO), and leg length discrepancy (LLD). OD-CVA was also correlated with PROs (ODI, SRS-22r) and complications. Pearson's correlation was used to determine the relationship between OD-CVA and radiographic parameters and PROs. Logistic regression was used to determine OD-CVA's relationship with complications. In multivariate logistic regression, age, SVA, and total instrumented levels were the three controlled variables. RESULTS A total of 243 patients underwent ASD surgery and 173 had a 2-year followup. The mean age was 49.3±18.3, BMI 25.5±5.7, and 67.1% (163/243) were female. The mean preop OD-CVA was 2.8±2.8 cm, immediate postop 1.9±1.6 cm, and 2-year postop 1.7±1.5 cm (p < 0.001 for preop vs postop, preop vs. 2-year postop). Preop OD-CVA correlated with preop C7-CVA (0.869, p<0.001), Max Cobb (0.168, p=0.009), PO (0.259, p<0.001), LLD (0.168, p=0.009). Postop OD-CVA was correlated with postop C7-CVA (0.787, p<0.001), PO (0.154, p=0.017). Preop OD-CVA correlated with preop ODI (0.167, p=0.011) and was better correlated than C7-CVA in some SRS-22r categories: total, image, and mental health. After univariate logistic regression, preop OD-CVA was associated with increased odds of major complication (OR=1.15, 95% CI 1.04-1.29, p=0.010). After multivariate regression, preop OD-CVA was still associated with increased odds of major complication (OR=1.18, 95% CI 1.04-1.36, p=0.012). CONCLUSIONS Preop OD-CVA correlated with radiographic parameters; higher preop OD-CVA correlated with worse PROs and had increased odds of postop complications. OD-CVA could be used to aid in ASD surgical planning and risk assessment. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs. The coronal alignment from the skull is understudied in adult spinal deformity (ASD) surgery. Previous literature on the odontoid-coronal vertical axis (OD-CVA) in an asymptomatic volunteer cohort showed its correlation with other radiographic parameters such as C7-CVA and thoracolumbar cobb angle. However, the correlation of OD-CVA with other radiographic parameters, surgical variables, patient-reported outcomes (PROs), and clinical outcomes in a symptomatic cohort is unknown. This project assesses how OD-CVA correlates with radiographic parameters and outcomes in a symptomatic cohort. A retrospective cohort of patients from multiple surgeons at a single institution. ASD patients with ≥6 fused levels were included in the symptomatic cohort for analysis. OD-CVA was analyzed alongside parameters, including C7-CVA, maximum coronal cobb angle (Max Cobb), lumbosacral fractional curve (LSFC), SVA, pelvic obliquity (PO), and leg length discrepancy (LLD). OD-CVA was also correlated with PROs (ODI, SRS-22r) and complications. Pearson's correlation was used to determine the relationship between OD-CVA and radiographic parameters and PROs. Logistic regression was used to determine OD-CVA's relationship with complications. In multivariate logistic regression, age, SVA, and total instrumented levels were the three controlled variables. A total of 243 patients underwent ASD surgery and 173 had a 2-year followup. The mean age was 49.3±18.3, BMI 25.5±5.7, and 67.1% (163/243) were female. The mean preop OD-CVA was 2.8±2.8 cm, immediate postop 1.9±1.6 cm, and 2-year postop 1.7±1.5 cm (p < 0.001 for preop vs postop, preop vs. 2-year postop). Preop OD-CVA correlated with preop C7-CVA (0.869, p<0.001), Max Cobb (0.168, p=0.009), PO (0.259, p<0.001), LLD (0.168, p=0.009). Postop OD-CVA was correlated with postop C7-CVA (0.787, p<0.001), PO (0.154, p=0.017). Preop OD-CVA correlated with preop ODI (0.167, p=0.011) and was better correlated than C7-CVA in some SRS-22r categories: total, image, and mental health. After univariate logistic regression, preop OD-CVA was associated with increased odds of major complication (OR=1.15, 95% CI 1.04-1.29, p=0.010). After multivariate regression, preop OD-CVA was still associated with increased odds of major complication (OR=1.18, 95% CI 1.04-1.36, p=0.012). Preop OD-CVA correlated with radiographic parameters; higher preop OD-CVA correlated with worse PROs and had increased odds of postop complications. OD-CVA could be used to aid in ASD surgical planning and risk assessment.