Learning retrograde intrarenal surgery as a sheathless and radiation-free technique.

The aim of this study was to evaluate the learning curve of inexperienced surgeon who can perform the operation on their own for access sheatless and radiation-free retrograde intrarenal surgery (RIRS) technique. Results of 70 consecutive patients who have renal stones and underwent RIRS which performed by a single surgeon were evaluated retrospectively. Cumulative stone free rates and fragmentation efficacy were taken as the primary outcomes for the learning curve analyses. Stone free rate was 74% (52/70). The learning curve constructed with moving average of cumulative stone free rates showed that learning curve of sheathless RIRS consisted of three phases; rapid ascent (0-15: phase 1), slight decline (16-35: phase 2) and plateau (36-70: phase 3). The number of case needed to obtain a final plateau in stone free rates was about 35. Fragmentation efficacy reached a plateau after 50 cases. The learning curve of access sheatless and radiation-free RIRS reached plateau phase after 35-50 cases. This steep learning curve points out that surgeons do not need to experience the classical RIRS technique before starting to perform access sheatless and radiation-free technique.