Learning curve of robot-assisted transabdominal preperitoneal (rTAPP) inguinal hernia repair: a cumulative sum (CUSUM) analysis.

Abstract

Robot-assisted transabdominal preperitoneal inguinal hernia repair (rTAPP-IHR) is a safe and feasible approach for hernias of varying etiology. We aim to present a single surgeon's learning curve (LC) of this technique based on operative times, while accounting for bilaterality and complexity. This is a retrospective cohort analysis of patients who underwent rTAPP-IHR over a period of 5 years. Patients who underwent primary, recurrent, and complex (previous posterior repair, previous prostatectomy, scrotal, incarcerated) repairs were included. Cumulative and risk-adjusted cumulative sum analyses (CUSUM and RA-CUSUM) were used to depict the evolution of skin-to-skin times and complications/surgical site events (SSEs) with time, respectively. A total of 371 patients were included in the study. Mean skin-to-skin times were stratified according to four subgroups: unilateral non-complex (46.8min), unilateral complex (63.2min), bilateral non-complex (70.9min), and bilateral complex (102min). A CUSUM-LC was then plotted using each procedures difference in operative time from its subgroup mean. The peak of the plot occurred at case number 138, which was used as a transition between 'early' and 'late' phases. The average operative time for the late phase was 15.9min shorter than the early phase (p < 0.001). The RA-CUSUM, plotted using the weight of case complexity and unilateral/bilateral status, also showed decreasing SSE rates after the completion of 138 cases (early phase: 8.8% vs. late phase: 2.2%, p = 0.008). Overall complication rates did not differ significantly between the two phases. Our study shows that regardless of bilateral or complex status, rTAPP operative times and SSE rates gradually decreased after completing 138 procedures. Previous laparoscopic experience, robotic team efficiency, and surgical knowledge are important considerations for a surgeon's LC.