High Modified 5 Factor Frailty Index is Associated With Worse PROMs and Decreased Return to Activities After 1 or 2 Level MI-TLIF.

Study Design: Retrospective cohort study.

Objective: Frailty is defined as a state of minimal "physiologic reserve." The modified 5 factor frailty index (mFI-5) is a recently proposed metric for assessing frailty and has been previously studied as a predictor of morbidity and mortality. However, its utility in predicting postoperative patient reported outcomes (PROMs) and return to activities remains understudied.

Methods: This is a retrospective cohort study of patients undergoing 1 or 2 level minimally invasive transforaminal lumbar interbody fusion queried from a prospectively maintained multi-surgeon registry. Comorbidities including hypertension, congestive heart failure, diabetes, chronic obstructive pulmonary disease, and functional status were utilized to calculate the mFI-5. Patients were separated into 3 cohorts, "non-frail," "moderately frail" or "severely frail" based on their mFI-5. Patient outcomes were compared between the cohorts.

Results: 392 patients were included of which 227 patients were non-frail, 134 were moderately frail, and 31 were severely frail. Frail patients had longer operative time ( = 0.002), greater estimated blood loss ( = 0.038). Despite similar preoperative PROMs, at a longer term follow up, frail patients also had worse PROM scores for ODI ( = 0.009), VAS-back ( = 0.028), and VAS-leg ( = 0.004). Frail patients had worse preoperative ( = 0.017) and postoperative ( < 0.001) SF-12 PCS. At 1-year, frail patients had lower rates of fusion ( = 0.002). Frail patients also demonstrated lower rates of returning to work ( = 0.018), returning to driving ( = 0.027), and discontinuation of narcotics ( = 0.004).

Conclusion: Frail patients as measured by the mFI-5 index demonstrated worse postoperative outcomes following 1 or 2 level MI-TLIF. Careful patient selection and preoperative optimization may be especially important in frail patients.