Objective:

To determine the predictive value of modified frailty index (mFI) in evaluating sarcopenia and clinical outcomes in patients undergoing 1- or 2-level transforaminal lumbar interbody fusion (TLIF) METHODS: Patients who underwent a one- or two-level TLIF between 2012 and 2020 were retrospectively identified. Frailty was compared among groups using mFI, while sarcopenia was classified by psoas muscle cross-sectional area. Bivariate statistics compared demographics, comorbidities, and clinical outcomes. A linear regression model was developed using Charlson Comorbidity Index (CCI) or mFI scores as independent variables to determine potential predictors for improvement in one-year patient reported outcomes.

Results:

Of 488 included patients, 60 were severely frail and 60 patients had sarcopenia, but sarcopenia was not associated with patient frailty (p=0.469). Severely frail patients had worse baseline ODI (p<0.001), MCS-12 (p=0.001), and PCS-12 (p<0.001), and worse improvement in ODI (p=0.037), PCS-12 (p<0.001), and VAS Back (p=0.007). mFI was an independent predictor of poorer improvement in VAS Back and ODI, while age + CCI additionally predicted poorer improvement in VAS Leg. Patients with higher mFI scores experienced longer length of stay, less frequent home discharge, and higher rates of complications, but similar readmission and reoperation rates.

Conclusions:

Frailer patients experience poorer improvement in back pain, physical functioning, and disability after TLIF. mFI and the combination of age and CCI comparably predict patient reported outcomes but do not correlate to baseline sarcopenia. Frailty increased the risk of complications, length of hospital stay, and risk of non-home discharge.