Learning curve of semi-rigid ureteroscopy for small calculi: how many cases are necessary?

INTRODUCTION: semi-rigid ureteroscopy is the procedure of choice for the treatment of ureterolithiasis, but it requires a learning curve to be performed safely. OBJECTIVE: To describe an estimate of the learning curve for performing semi-rigid ureterorenolithotripsy in patients with small-sized ureterolithiasis and to estimate the minimum number of procedures necessary to safely perform the surgical procedure. METHODS: this is a prospective study evaluating the learning curve of a resident of urology in the first 60 semirigid ureteroscopies in patients with ureterolithiasis up to 1cm. The patients were divided into three groups: Group I one to twenty surgeries, Group II twenty one to forty surgeries and Group III forty one to sixty surgeries. The surgeries were recorded and analyzed by two urologists experienced in endourology. A qualitative analysis was performed based on a previously validated tool and a quantitative analysis. RESULTS: all qualitative variables had significant variation between Groups I and II (p<0.001), and between Groups I and III (p<0.001). There was a difference in time to access the ureter, passage of a double J catheter and total operative time between Groups I and II (p<0.001) and Groups I and III (p<0.001). CONCLUSION: after 40 cases there seems to be little increase in both quantitative as well as qualitative evaluation in surgical performance for performing semi-rigid ureterolithotripsy safely in calculations up to 1cm.