267. Establishing safety thresholds for surgical invasiveness based on frailty status in ASD surgery

Abstract

<h3>BACKGROUND CONTEXT</h3> Both frailty and surgical invasiveness are correlated with increased risk of complications following ASD surgery, yet there is no accepted risk-stratification system combining these factors. <h3>PURPOSE</h3> The aim of this study is to ascertain data-driven categories defining the risk for 90-day complications following ASD surgery based on frailty and surgical invasiveness. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of a multicenter database. <h3>PATIENT SAMPLE</h3> A total of 1,272 surgical ASD patients undergoing spinal fusions ≥5 levels <h3>OUTCOME MEASURES</h3> Ninety-day complication risk, 90-day complication rate, invasiveness thresholds for increased complications. <h3>METHODS</h3> Using a prospective, multicenter database, we identified 1,272 surgical ASD patients undergoing posterior spinal fusion of at least five levels. Patients were separated into three frailty groups based on the ASD-FI frailty index. Within each frailty group, stratum-specific likelihood ratio (SSLR) analyses were performed to define frailty-based surgical invasiveness cutoffs associated with increased risk for 90-day complications. Cutoffs generated through SSLR were confirmed with multivariable logistic regression analysis controlling for age, alignment, and ODI. <h3>RESULTS</h3> Mean age was 60 ± 14 years, 74% females. Of 1,272 surgical ASD patients, 319 (35%) were nonfrail (NF), 667 (52%) frail (F), and 286 (23%) severely frail (SF). Mean SI was 93 ± 35. The mean complication rate was 35.4% for NF, 37% for F and 43.6% for SF. SSLR analysis of NF patients produced 2 complication categories: 33% complication rate for SI < 153 and 73% for SI ≥ 153. NF patients with SI ≥ 153 had 4.14x higher odds of complications than NF patients with SI <153 (p=0.04). SSLR analysis of F patients produced 3 complication categories: 26% complication rate for SI < 60, 42% for SI of 60 to 179, and 64% for SI ≥ 180. Relative to F patients with SI < 60, F patients with SI 60 to 179, and SI ≥ 180 had 2.4x and 6.7x higher odds of complications, respectively (p<0.01 for both). SSLR analysis of SF patients produced 2 complication categories: 35% complication rate for SI < 82 and 49% complication rate for SI ≥ 82. SF patients with SI ≥ 82 had 1.77x higher odds of complications than SF patients with SI < 82 (p=0.04). <h3>CONCLUSIONS</h3> Frailer groups were found to have lower SI cutoffs, indicating the less invasiveness surgeries can be performed on frail patients to minimize complication risk. This risk-stratification system is useful for counselling patients regarding their risk of complication. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.