Medical Student Northwestern University Feinberg School of Medicine
Introduction: Despite the high annual volume of Posterior Lumbar Interbody Fusion (PLIF) surgeries, few studies have studied baseline frailty in this patient population using nationally-representative data. The novel Risk Analysis Index (RAI) may help surgeons stratify risk in frail populations and contribute to the broader spine outcomes research literature.
Methods: Retrospective cohorts of PLIF patients were queried from the 2018-2019 Nationwide Readmissions Database (NRD) using The International Classification of Disease, Tenth Edition, Procedure Coding System (ICD-10-PCS) codes. The modified 5-item Frailty Index (mFI-5) and RAI were calculated, analyzed, and compared with respect to postoperative outcomes discrimination. Primary endpoint was non-home discharge disposition (NHD) and secondary endpoints were overall complications, extended length of stay (eLOS) (>75th percentile), and mortality. The receiver operating characteristic curve (ROC) evaluated the discriminatory accuracy of baseline frailty for the primary endpoint.
Results: A total of 120,155 elective PLIF hospitalizations were analyzed. Frailty (measured by RAI) was binned into 4 categories: 0-10 (11%), 11-15 (17.7%), 16-20 (20.2%), and 21+ (33.2%). In total, there were 38,508 complication occurrences, 26,320 NHDs, and 218 deaths. Increasing RAI score was significantly associated with increased rates of postoperative complications, NHD, and eLOS (p < 0.001). The discrimination accuracy of RAI was superior to that of mFI-5 for the primary endpoint of NHD (C-statistic 0.696 vs. 0.617, DeLong test p< 0.001).
Conclusion : The RAI frailty score was associated with all short-term outcomes after elective PLIF in a large nationwide database and demonstrated robust discriminatory accuracy for the primary endpoint of non-home discharge. These findings will help better identify high-surgical risk PLIF populations predisposed to adverse events and allow surgeons to optimize risk stratification for better surgical outcomes.
.jpg "Kranti C. Rumalla, BA photo")