Defining the Learning Curve of Flexible Ureterorenoscopy and Laser Lithotripsy

To investigate the impact of learning curve (LC) on flexible ureterorenoscopy (f-URS).

Patients who underwent kidney stone surgery in a urology clinic from a tertiary health care institution with f-URS were enrolled in the study. Patient characteristics, the properties of kidney and kidney stones were recorded. Also, f-URS-related parameters, hospitalization time, the success of the procedure, and complications were noted. Patients were categorized equally into 4 groups, the first 20 f-URS cases in Group 1, and the last 20 f-URS cases in Group 4. Groups were compared according to patient preoperative parameters, intraoperative outcomes, success rate and complication rate.

Time from the induction of anaesthesia to insertion of flexible ureterorenoscope was 18.6 min in group 1 and 17.2 min in group 2; then it significantly decreased to 15.0 min for cases 40 through 60 and 12.4 min for cases 60 through 80 (p = 0.001). Operation time in group 3 and group 4 was significantly shorter than in group 1 and group 2 (p = 0.001). Also, fluoroscopy time was significantly longer in group 1 (82.9 seconds) and reached a plateau in group 3 (50.3 seconds) and group 4 (41.7 seconds) (p = 0.001). Additionally, after the 20th case, we achieved a significantly higher success rate in comparison to the first 20 cases (65% in group 1, 85% in group 2, 85% in group 3, and 90% in group 4, p = 0.001).

Flexible ureterorenoscopy is a surgery that requires high technique and experience. The present study found that success of f-URS reached satisfactory levels after 20th cases. In addition, 40 cases may be enough for surgical proficiency regarding decreases in preparation time, operation time, and fluoroscopy time.