How many cases are necessary to develop competence for laparoscopic radical nephrectomy?

We evaluated the number of cases necessary to develop competence for performing laparoscopic radical nephrectomy (LRN) by chronologically analyzing the results of 150 cases. 150 patients were included in this study, each of whom had had pure transperitoneal LRNs between March 2003 and February 2008 performed by three surgeons who were all novices in laparoscopic surgery. Each surgeon performed 50 LRNs. These were divided into 10 groups chronologically, with five cases in each group (individual-group). Subsequently, we combined the data of the three surgeons, with 15 cases assigned to each group (combined-group). We identified the groups that demonstrated a statistically significant difference in operative time, compared with the most recent group. Based on this finding, we divided the cases into two groups: The novice group and the competent group. The complication rate, transfusion rate, and estimated blood loss were then compared between the two groups. The total average operative time was 187.6 +/- 46.56 minutes; from group 4 onward, there was no significant decrease in the operative time. Therefore, groups 1 to 3 were defined as the novice groups, and groups 4 to 10 as the competent groups. Incidence of intraoperative complications was six (13.3%) in the novice group and nine (8.6%) in the competent group. There were 14 cases with postoperative complications--4 (8.9%) in the novice group and 10 (9.5%) in the competent group. There were significant differences in the estimated blood loss and transfusion rate between the novice and competent groups (236.4 +/- 41.85 mL vs 191.5 +/- 21.9 mL, 17.8% vs 4.8%, respectively). Our results suggest that 15 cases are needed for a novice surgeon to achieve competence in LRN. Surgical outcomes and morbidity can be improved once this learning curve has been overcome.