Assessing Frailty Screening Tools for Predicting Morbidity for Suboccipital Decompression in Adults with Chiari Malformation Type I

Introduction: The revised risk analysis index (RAI-rev) and 5-factor modified frailty index (mFI-5) are frailty assessment tools that have been used to predict neurosurgical outcomes. The aim of this study is to investigate the utility of these tools to predict extended hospital length of stay (LOS), non-routine discharge (NRD), and 30-day adverse events (AEs) among patients with Chiari malformation type I (CM-I) undergoing suboccipital decompression.

Methods: We conducted a retrospective cohort study using the 2011-2022 ACS NSQIP database to identify adults with Chiari malformation type I who underwent suboccipital decompression. Using receiver operating characteristic (ROC) and multivariable analyses, we compared the discriminative thresholds and independent associations of the revised risk analysis index (RAI-rev), 5-factor modified frailty index (mFI-5), and patient age with extended LOS, NRD, and 30-day AEs.

Results: Among 1,225 patients studied, 992 (81.0%) were female, and 732 (66.6%) were non-Hispanic White. RAI-rev categorized 806 (65.8%) as robust, 388 (31.7%) as typical and 31 (2.5%) as frail patients, compared to mFI-5's identification of 946 (77.2%) as robust, 222 (18.1%) as typical, and 57 (4.7%) as frail patients. In predicting extended LOS, there were no significant differences between RAI-rev (AUC 0.5608), mFI-5 (AUC 0.5626), and age (AUC 0.5496). Similarly, no differences were observed between RAI-rev, mFI-5, and age in predicting 30-day AEs. Notably, RAI-rev (AUC 0.7234) exhibited superior performance in predicting NRD compared to mFI-5 (p = 0.038) and age (p = 0.016). Multivariable analysis revealed RAI-rev [aOR: 4.37, 95% CI: 1.40–13.70] and mFI-5 [aOR: 2.71, 95% CI: 1.38–5.32] as significant predictors of extended LOS for frail patients. RAI-rev was also a significant predictor of NRD for typical [aOR: 2.57, 95% CI: 1.00–6.60] and frail [aOR: 15.70, 95% CI: 3.27–75.44] patients. Neither RAI-rev nor mFI-5 significantly predicted 30-day AEs.

Conclusion : Our findings emphasize the significance of integrating frailty assessments into the preoperative evaluation of adults with CM-I undergoing suboccipital decompression. The revised risk analysis index (RAI-rev) showed superior predictive ability for non-routine discharge. Using frailty screening can improve patient care and outcomes.