109. Are we missing the bigger comorbidity picture? Metabolic syndrome worsens alignment and increases mechanical complications following adult spinal deformity surgery

BACKGROUND: Metabolic syndrome may influence recovery after complex spine surgery. In patients undergoing adult spinal deformity (ASD) surgery, we evaluated the relationship between metabolic syndrome and postoperative alignment, complications, and patient-reported outcome measures (PROMs). METHODS: . The primary outcomes were the following: alignment, evaluated as sagittal vertical axis >5 cm or L1-pelvic angle not within 5° of target, or coronal vertical axis >3 cm; and medical and mechanical complications. Secondary outcomes were 2-year Oswestry Disability Index scores. Multivariable regression controlled for age, sex, prior fusion, operative time, and preoperative alignment/PROMs. RESULTS: Of 288 patients undergoing ASD surgery, 31 (11%) had metabolic syndrome. Patients with metabolic syndrome were significantly older (71 ± 8 vs. 62 ± 18 years; P < 0.001) and had a higher preoperative muscle-to-vertebral body ratio, indicating sarcopenic obesity (β = 0.6; 95% CI, 0.3-0.9; P < 0.001). Metabolic syndrome was independently associated with higher rates of postoperative sagittal vertical axis (>5 cm) (OR, 5.2; 95% CI, 1.4-19.0). Metabolic syndrome was not associated with medical complications (all P > 0.05). Metabolic syndrome was independently associated with rod fractures/pseudarthrosis (OR, 4.0; 95% CI, 1.6-10.1; P = 0.003).Two-year PROMs were similar between the cohorts (all P > 0.05). CONCLUSIONS: Preoperative metabolic syndrome was independently associated with postoperative sagittal malalignment and rod fractures/pseudarthrosis. Continued awareness of metabolic syndrome may enable surgeons to holistically address the syndrome preoperatively.