Practice composition and sub-specialization among fellowship-trained HPB surgeons: impact on outcomes following hepatopancreatic surgery.

INTRODUCTION: The impact of sub-specialization and practice composition among surgeons performing hepatopancreatic (HP) surgery in the United States has not been previously characterized. METHODS: Medicare beneficiaries undergoing HP surgery (2016-2021) were identified. HP practice composition, defined as the proportion of HP procedures among all surgeries performed by each surgeon during the study period was assessed. The primary outcome was achievement of textbook outcome (TO) after HP surgery relative to HP practice composition. RESULTS: A total of 20,614 HP procedures were performed by 710 fellowship-trained surgeons (CGSO:n = 578, 81.4%, AHPBA:n = 111, 15.6%, both n = 21, 3.0%). Most surgeons were low-volume for both hepatic and pancreatic surgery (H-low/P-low:41.1%). CGSO and AHPBA fellowship graduates had comparable liver and pancreas volume practices (p = 0.24). Median HP practice composition among all surgeons was 20.7% (IQR:10.1-35.7%). Higher HP-specific volume and higher HP practice composition were independently associated with a greater probability of TO after hepatectomy and pancreatectomy (both p < 0.05). Among CGSO graduates, HP practice composition varied significantly by graduating CGSO program. CONCLUSIONS: HP case composition varied markedly relative to fellowship training. Despite greater HP case composition being associated with improved outcomes, most fellowship-trained HP surgeons maintained broad-based and low volume HP practices.