Learning Curve of Single-site Robotic Cholecystectomy: A Cumulative Sum Analysis

Minimally invasive surgery has significantly improved cosmesis and clinical outcomes after either laparoscopic or robotic cholecystectomy. In an effort to minimize the number of incisions in multiport procedures, single-site approaches have been developed. However, single-site robotic cholecystectomy (SSRC) can be technically challenging for novice surgeons. The goal of this study is to establish the learning curve (LC) of SSRC through an assessment of operative times and clinical outcomes.

A retrospective analysis of patients undergoing SSRC over a period of 5 years was performed. Consecutive cholecystectomy cases were assessed based on the procedure setting (elective vs. emergent). Cumulative sum analysis were used to establish the LC through an evaluation of the skin-to-skin (STS) time and postoperative complications rate. Afterward, a direct comparison was performed between the established phases.

This study included a total of 259 SSRCs with an overall mean STS time of 41.1 minutes. Elective cases took on average of 38.8 minutes, whereas emergent cases spanned over 60.5 minutes ( P= 0.005). The cumulative sum-LC was obtained by summing the differences between each procedure's STS time, revealing a quadratic best-fit line maximum and an inflection point between the early and late phases at case 91. A significant difference between STS time was seen between the early and late phases (53.8 vs. 30.0 min, P< 0.0001). There were no significant differences in terms of postoperative complications between the 2 phases. Incisional hernia rates were comparable between the 2 phases (early: 4.4% vs. late: 2.5%, P< 0.461).

This is the largest study to assess the LC of SSRC through operative time and clinical outcomes. A steady decrease in STS time was observed during the completion of the first 91 consecutive cases.