Introduction: Adult spine deformity (ASD) surgery is more frequently being performed in frail patients. Although surgical outcomes are largely successful, there remains significant risk of poor outcomes. The ideal length of fusion constructs in these patients remains debatable.
Methods: ASD patients undergoing T9-to-Pelvis fusion were stratified by ASD-modified frailty index into not frail (NF), frail (F) and severely frail (SF) categories. ASD was defined as at least one of: scoliosis ≥20°, sagittal vertical axis [SVA] ≥5 cm, or pelvic tilt ≥ 25°. Means comparisons tests were used to assess differences between both groups. Logistic regression analyses were used to analyze associations between frailty categories, upper instrumented vertebra (UIV) and outcomes.
Results: 477 patients included (Age: 60.3 ± 14.9 years, BMI: 27.5 ± 5.8 kg/m2, CCI: 1.67 ± 1.66). 74% of patients were female. 49.6% of patients were NF, 35.4% F and 15% SF. At baseline (BL), differences in age, BMI, CCI and deformity were significant (all p=0.001). 15.5% of patients had experienced mechanical complications (MCs) by 2 years (8.1% NF, 15.1% F & 16.3% SF, p=0.013). Reoperations also differed between groups (20.2 vs 23.3 vs 32.6%, p=0.011). Controlling for osteoporosis, baseline deformity and degree of correction (by SAAS-matching), F and SF patients were more likely to experience MCs if they had: heart failure (OR 6.6, 95% CI 1.6-26.7, p=0.008), depression (OR 5.1, 1.1-25.7, p=0.048) and cancer (OR 1.5, 1.1-1.4, p=0.004). F/SF patients experienced higher MC than NF at 2 years (19 vs 11.9%, p=0.003). When controlling for BL deformity and degree of correction in SF vs F patients, SF patients were less likely to experience clinically relevant proximal junctional kyphosis/failure or MCs by 2 years with more proximal UIVs.
Conclusion : Frail patients are at risk for poor outcomes following ASD surgery due to their comorbidities. Although definitively prescriptive upper instrumented vertebra remains elusive, these patients appear to be at greater risk for poor outcomes when this is sited more distally.
.jpg)