Multidimensional analysis of the learning curve for laparoscopic colorectal surgery: lessons from 1,000 cases of laparoscopic colorectal surgery

We consider quality of surgery throughout the learning curve and attempt to determine the learning curve for competency in performing laparoscopic colorectal surgery. The study included 1,014 patients who underwent laparoscopic colorectal resection between June 1996 and December 2007. We categorized patients into nine periods according to number of cases performed. Operative time continuously decreased for right hemicolectomy (216 versus 150 min) and anterior resection (214.8 versus 147.7 min), whereas for low anterior resection it did not change over many periods and then significantly decreased after the ninth period (221.3 versus 176.4 min). The proportion of patients who had undergone previous abdominal surgery increased after the second period. Anastomotic leakage rate was 6-9% for the first 200 cases, and then decreased to less than 2%. More than 10% of operations were converted to open surgery during the first period, after which this rate significantly decreased to 2%. Number of harvested lymph nodes stabilized to 35-40 for right hemicolectomy after 200 cases, whereas for anterior and low anterior resection it was consistently 15-20 after the initial 20 cases. Overall, disease recurrence rate was 16-25%. For rectal cancer, local recurrence rate was highest (12%) in the fourth period and decreased thereafter to about 3%. Postoperative complications and local recurrence rate increased even after accumulation of experience because of expansion of indications for laparoscopic procedures.