A pragmatic evaluation of outcome fragility in randomized clinical trials comparing open microdiscectomy and...

RCTs comparing endoscopic-assisted and open lumbar discectomy frequently show significant findings despite few events and inconsistent follow-up, undermining confidence in their robustness. Fragility analysis measures how easily significance disappears with minimal data changes. This study systematically examined the statistical and clinical fragility of trials contrasting these 2 surgical approaches.

PubMed, Embase, and Cochrane CENTRAL were searched from January 2000 through December 2024 for RCTs comparing MD and EM for LDD. Dichotomous outcomes were evaluated using the fragility index (FI) and fragility quotient (FQ), while continuous outcomes were assessed using the continuous fragility index (CFI) and the continuous fragility quotient (CFQ). Practical fragility was determined by comparing fragility indices with the loss to follow-up (LTF). Outcomes were stratified by clinical categories for subgroup analyses.

Thirteen RCTs, including 1,826 patients, were included. We identified 108 dichotomous events, with a median FI of 4 (interquartile range [IQR], 3-6) and median FQ of 0.035. Neurological complications demonstrated the greatest statistical fragility, and the collective body of dichotomous events was practically fragile. About 138 continuous outcomes were analyzed, with a median CFI of 11 (IQR 6-17) and a CFQ of 0.17. Continuous outcomes were more statistically robust and not practically fragile. No significant correlation existed between statistical significance and fragility.

RCTs comparing open and endoscopic-assisted microdiscectomy are frequently fragile, especially for dichotomous outcomes that often fall below LTF thresholds. Caution should be taken when interpreting these results, and the fragility metric can help maintain reporting veracity across orthopedic literature.