The Measurements of Frailty and Their Possible Application to Spinal Conditions. A Systematic Review

Abstract Background: Frailty is associated with an increased risk of postoperative adverse events (AEs) within the surgical spine population. Multiple frailty tools have been reported in the surgical spine literature. However, the applicability of these tools remains unclear. The primary objective of this systematic review is to appraise the construct, feasibility, objectivity, and clinimetric properties of frailty tools reported in the surgical spine literature. Secondary objectives included determining the applicability and the most sensitive surgical spine population for each tool. Methods: This systematic review was registered with PROSPERO: CRD42019109045. Publications from January 1950 to December 2020 were identified by a comprehensive search of PubMed, Ovid, Embase, and Cochrane, supplemented by manual screening. Studies reporting and validating a frailty tool in the surgical spine population with a measurable outcome were included. Each tool and its respective clinimetric properties were evaluated using validated criteria and definitions. The applicability of each tool and its most sensitive surgical spine population was determined by panel consensus. Bias was assessed using the Newcastle-Ottawa Scale.Results: 47 studies were included in the final qualitative analysis. A total of 14 separate frailty tools were identified, in which nine tools assessed frailty according to the cumulative deficit definition, while four instruments utilized phenotypic or weighted frailty models. One instrument assessed frailty according to the comprehensive geriatric assessment (CGA) model. Twelve measures were validated as risk stratification tools for predicting postoperative AEs, while one tool investigated the effect of spine surgery on postoperative frailty trajectory. The modified frailty index (mFI), 5-item mFI, adult spinal deformity frailty index (ASD-FI), FRAIL Scale, and CGA had the most positive ratings for clinimetric properties assessed. Conclusions: The assessment of frailty is important in the surgical decision-making process. Cumulative deficit and weighted frailty instruments are appropriate risk stratification tools. Phenotypic tools are sensitive for capturing the relationship between spinal pathology, spine surgery, and prehabilitation on frailty trajectory. CGA instruments are appropriate screening tools for identifying health deficits susceptible to improvement and guiding optimization strategies. Studies are needed to determine whether spine surgery and prehabilitation are effective interventions to reverse frailty.