Risk Analysis Index Has Greater Association with Post-surgical Outcomes Following Elective Resection of Vestibular Schwannomas Than the Modified Frailty Index

Introduction: Frailty, the state of decreased immunity to stressors, is used to predict postoperative morbidity and mortality. The predictive value of the Revised Risk Analysis Index (RAI-rev) has yet to be applied to outcomes of neurosurgical resection of vestibular schwannomas. This study aims to compare the utility of this index with the more common 5-item modified frailty index (mFI-5).

Methods: The National Surgical Quality Improvement Program database, administered by the American College of Surgeons, was utilized to extract adult patients who underwent elective vestibular schwannoma surgery from 2012-2020. Univariable analysis with simple logistic regression was performed for each frailty index on the outcomes of Clavien-Dindo grade IV complications (CDIV), extended length of hospital stay (eLOS), non-home discharge destination (NHD), reoperation, readmission. For each outcome, a Cochran-Armitage significance test was conducted to compare odds ratios (OR) and their 95% confidence intervals.

Results: A total of 1,832 patients were included. RAI-rev showed an increasing likelihood of CDIV (pre-frail OR 1.91, frail OR 6.8; trend test p=0.003), eLOS (pre-frail OR 1.31, frail OR 5.2; trend test p=0.003), NHD (pre-frail OR 2.86, frail OR 57; trend test p< 0.001), reoperation (pre-frail OR 1.53, frail OR 3.60; trend test p=0.024), and readmission (pre-frail OR 1.78, frail OR 2.16; trend test p< 0.001]). Associations for mFI-5 were not as strong and did not always show an increasing likelihood of the outcome variables.

Conclusion : Neurosurgeons should consider patient frailty as a predictor of vulnerability to poor outcomes when recommending appropriate management of vestibular schwannomas. In particular, because of RAI-rev’s superiority to mFI-5 in predicting such outcomes, it is the better index to aid in this decision.