Adopting for Supine Percutaneous Nephrolithotomy: Analyzing the Learning Curve of Tertiary Academic Center Urology...

To evaluate the effect of learning curve on supine mini-percutaneous nephrolithotomy (PNL) outcomes.

The aim of the study was to include a total of 75 patients. All of the patients were operated on by the same team, which had experience of at least 100 prone mini-PNL cases. The team was led by a surgeon who had observed 40 supine conventional PNL procedures (sheath size 24 Fr) over a period of 3 months at an endourology center with experience in supine PNL and surgeries were performed by the same primary surgeon. Patients were divided equally into 5 groups, as first 15 cases in Group 1, and final 15 in Group 5. Groups were compared according to preoperative characteristic, intraoperative result, complication rate, and success rate.

The mean access time was 14 minutes in group 1. It decreased to mean of 10.3 minutes for cases 31 through 45, and afterward significant decrease occurred up to a mean of 6.5 minutes for cases 61 through 75 (P ≤.001). According to the Clavien-Dindo classification system, complications were assessed, and a decrease was observed from group 1 to group 5 (40%, 20%, 26.6%, 6.7%, and 13.3%, respectively). The stone free rate increased from the mean of 66.7% for the first two groups to 80% for group 3 and increase up to the 93.3% for group 4 and 5 (P = .128).

The present study showed that considering the decrease in access time and operation time 60 patients could be enough for surgical competency as well as the complications and stone-free rates reached satisfactory levels after 45 patients.