Clinical Outcomes and Mechanical Complications After Adult Spinal Deformity Surgery in Patients Aged 80 Years or Older: A Propensity Score-Matched Comparative Study

Study Design Retrospective cohort study. Objectives To compare outcomes after adult spinal deformity (ASD) surgery between patients aged 80 years or older and those younger than 80 years. Methods We retrospectively reviewed patients aged 65 years or older with ASD who underwent long-segment posterior corrective fusion. Patients were divided into 2 groups according to age at surgery (<80 years and ≥80 years). Propensity score matching was performed to adjust for baseline differences between groups. Because PJFx was more frequent in the super-elderly group, logistic regression analysis was additionally performed to identify factors associated with PJFx in patients aged 80 years or older. Results A total of 386 patients were included, of whom 90 were aged 80 years or older. Before matching, the super-elderly group had significantly higher rates of PJFx and mechanical failure. After matching, 60 pairs were analyzed, and no significant differences in mechanical complications were observed between the groups. In patients aged 80 years or older, lower upper instrumented vertebra Hounsfield unit value and lower postoperative sacral slope were independently associated with PJFx. Conclusions After adjustment for baseline characteristics, postoperative mechanical complication rates were comparable between age groups. Risk stratification in super-elderly patients should incorporate bone quality and the postoperative mechanical environment rather than chronological age alone.