Development of a Modified Cervical Deformity Frailty Index: A Streamlined Clinical Tool for Preoperative Risk Stratification.

STUDY DESIGN: Retrospective review OBJECTIVE.: Develop a simplified frailty index for CD patients SUMMARY OF BACKGROUND DATA.: To improve preoperative risk stratification for surgical cervical deformity (CD) patients, a CD frailty index (CD-FI) incorporating 40 health deficits was developed. While novel, the CD-FI is clinically impractical due to the large number of factors needed for its calculation. To increase clinical utility, a simpler, modified CD-FI (mCD-FI) is necessary.

METHODS: CD patients (C2-C7 Cobb>10°, CL>10°, cSVA>4 cm, or CBVA>25°) >18yr with preoperative CD-FI component factors. Pearson bivariate correlation assessed relationships between component deficits of the CD-FI and overall CD-FI score. Top deficits contributing to CD-FI score were included in multiple stepwise regression models. Deficits from model with largest R were dichotomized, and the mean score of all deficits calculated, resulting in mCD-FI score from 0 to 1. Patients were stratified by mCD-FI: Not Frail (NF, <0.3), Frail (0.3-0.5), Severely Frail (SF, >0.5). Means comparison tests established correlations between frailty category and clinical outcomes.

RESULTS: Included: 121 CD patients (61 ± 11yr, 60%F). Multiple stepwise regression models identified 15 deficits as responsible for 86% of the variation in CD-FI; these factors were used to construct the mCD-FI. Overall, mean mCD-FI was 0.31 ± 0.14. Breakdown of patients by mCD-FI category: NF: 47.9%, Frail: 46.3%, SF: 5.8%. Compared to NF and Frail, SF patients had the longest inpatient hospital stays (P = 0.042), as well as greater baseline neck pain (P = 0.033), inferior NDI scores (P<0.001) and inferior EQ-5D scores (P < 0.001). Frail patients had higher odds of superficial infection (OR:1.1[1.0-1.2]), and SF patients had increased odds of mortality (OR:8.3[1.3-53.9]).

CONCLUSIONS: Increased frailty, assessed by mCD-FI, correlated with increased length of stay, neck pain, and decreased health-related quality of life. Frail patients were at greater risk for infection, and severely frail patients had greater odds of mortality. This relationship between frailty and clinical outcomes suggests that mCD-FI offers clinical utility as a preoperative risk stratification tool.

LEVEL OF EVIDENCE: 3.