The Learning Curve of Robotic-Assisted Low Rectal Resection of a Novice Rectal Surgeon

With the increasing availability of the surgical robotic system, the young generation colorectal surgeons may learn robotic-assisted rectal surgery upfront. There are currently very limited studies evaluating the learning curve of novice rectal surgeons.

This study aimed to evaluate the learning curve of a surgeon who had limited experience in open and laparoscopic rectal surgery.

Thirty-nine consecutive robotic-assisted total mesorectal excisions were performed from March 2013 to October 2014. All cases were performed by a single surgeon whose prior experience in open or laparoscopic low rectal cancer resections was <5 cases. The learning curve was analyzed using the cumulative sum method.

Thirty-four low anterior resections, four abdomino-perineal resections, and one Hartmann's operation were performed. The mean total operating time was 397.2 ± 184.3 min. There was no conversion. The major complication rate was 10.3 %. When total operating time was analyzed with the CUSUM method, three phases could be identified. They are the initial eight cases, middle 17 cases, and the final 14 cases. The first phase consisted of more proximal tumors (86.3 ± 20.7 vs. 58.0 ± 34.9 mm from anal verge, p = 0.04) and was associated with a shorter total operating time (243.5 ± 38.0 vs. 540.9 ± 133.4 min, p = 0.000) and less estimated blood loss (81.3 ± 25.9 vs. 168.8 ± 99.5 ml, p = 0.02) compared to the second phase. When the third phase is compared with the first and second phase, it has shorter total operating time (310.6 ± 164.5 vs. 44 5.7 ± 179.8 min, p = 0.03). Complications rate were 12.5, 17.6, and 0 % for phase one, two, and three respectively.

In this study, the learning curve for a novice rectal surgeon was 25 cases. This is comparable to those who have already mastered the technique with laparoscopic or open approach. Surgical robotic system may have a role in shortening the learning curve for low rectal resection.