Spinal Surgery in Patients Aged 80 Years and Older: Risk Stratification Using the Modified Frailty Index.

mFI scores of ≥3/11 variables were associated with a higher risk of postoperative morbidity in patients aged ≥80 years undergoing spinal surgery. The mFI-associated risk stratification provides a valuable adjunct in surgical decision making for this rapidly growing subpopulation of patients.