Training the Next Generation of Minimally Invasive HPB Surgeons: Are Current Fellowships Crossing the Learning Curve?

Technical Summary: Training the Next Generation of Minimally Invasive HPB Surgeons

Problem Statement
Hepatopancreatobiliary (HPB) surgery is characterized by high technical complexity, where surgeon volume correlates directly with patient outcomes. While minimally invasive surgery (MIS), particularly robotic platforms, offers improved patient outcomes, its adoption is hindered by steep learning curves and technical demands. Currently, specialized HPB training in the Americas is distributed across three distinct fellowship pathways certified by the Americas Hepatopancreatobiliary Association (AHPBA): dedicated HPB surgery, Complex General Surgical Oncology (CGSO), and Transplant (TXP) surgery.

Despite all three pathways producing surgeons who achieve similar clinical volumes in independent practice, there is a lack of comparative data regarding the equity of operative MIS exposure across these tracks. The structural requirements of CGSO (non-HPB oncology mandates) and TXP (multi-organ transplantation mandates) may result in divergent case mixes, potentially leaving fellows in certain pathways underprepared for the technical demands of modern robotic HPB surgery. The study addresses the critical question of whether current fellowship curricula are effectively crossing the learning curve for complex MIS procedures.

Methodology
This study is a retrospective analysis of anonymized Fellowship Council case log data from fellows graduating between 2014 and 2023 who pursued AHPBA certification.

• Cohort: The study included 146 HPB fellows (from 24 programs), 55 CGSO fellows (from 8 programs), and 51 TXP fellows (from 7 programs).
• Data Scope: Case volumes were analyzed as total experience per fellowship, regardless of whether the program was a one-year or two-year track.
• Categorization: Procedures were classified by platform (open, robotic, laparoscopic) and type, specifically focusing on pancreaticoduodenectomies (PD), distal pancreatectomies (DP), non-cholecystectomy biliary operations, anatomic liver resections, and non-anatomic liver resections.
• Statistical Analysis: Continuous variables were compared using one-way ANOVA with post-hoc Tukey testing. Temporal trends were evaluated using mixed-effects models to account for program-level clustering. Significance was defined as p < 0.05.

Key Contributions and Results
The study characterizes significant disparities in MIS operative exposure across the three training pathways, revealing a shift toward robotic surgery that is not uniformly distributed.

1. Robotic Experience Disparity:

   • HPB Fellows: Logged the highest volume of robotic cases overall (mean 12.5), significantly outperforming CGSO (8.5) and TXP (1.0) fellows (p < 0.01).
   • Specific Robotic Procedures: HPB fellows logged significantly more robotic PDs (4.4 vs. 3.0 for CGSO and 0.2 for TXP) and robotic distal pancreatectomies (3.8 vs. 3.2 for CGSO and 0.6 for TXP).
   • Liver Resections: While TXP fellows performed more open anatomic liver resections (35.2 vs. 24.0 for HPB), HPB fellows performed significantly more robotic anatomic (2.1 vs. 0.03 for TXP) and non-anatomic liver resections (1.8 vs. 0.2 for TXP).

2. Evolution of Case Mix:

   • Over the 10-year period, average robotic case volume increased nearly 11-fold (from 1.7 to 18.7).
   • Despite this global increase, TXP fellows remain rooted in an open surgical paradigm, lagging significantly in robotic exposure compared to HPB and CGSO tracks.

3. Proficiency Thresholds:

   • Crucially, the study found that no fellow in the cohort exceeded the estimated learning curve thresholds for proficiency (estimated at 30–50 cases for robotic PD and major hepatectomy).
   • Even in the highest-volume track (HPB), the average graduation volume fell significantly short of these thresholds. Several HPB fellows were within five cases of the 40-case robotic PD threshold, but none completed enough to be considered proficient.

4. Operative Independence:

   • Across all tracks, fellows performed the majority of cases as primary surgeons (85–91%), with no statistically significant difference in the role (primary vs. assistant) among the three groups.

Significance and Claims
The paper claims that meaningful differences in MIS operative exposure exist across training pathways, with TXP fellows trailing significantly in robotic experience. The authors assert that while HPB and CGSO fellowships have pivoted toward robotic surgery, the transplant-based pathway remains focused on open techniques, likely due to the time-critical nature of transplant operations and competing clinical mandates.

The study highlights a critical gap: no single training pathway currently provides a comprehensive experience for robotic mastery. The authors emphasize that while total case volumes have remained stable, the case mix has shifted. However, because current graduation volumes across all tracks fall below established learning curve thresholds for complex robotic operations, the authors argue for:

• Standardized MIS Curricula: To ensure technical proficiency across all HPB surgery pipelines.
• Competency-Based Assessment: Moving beyond simple case logs to observational assessments of surgical independence (EPAs).
• Program Adaptation: Fellowship programs must anticipate the growing demand for minimally invasive HPB surgeons and ensure graduates are equipped with skills across multiple platforms (open, laparoscopic, and robotic).

The authors conclude that the lack of exposure to specific platforms may negatively affect patient safety and surgeon autonomy in early practice, necessitating a re-evaluation of how training pathways prepare surgeons for the evolving technical demands of the field.