Safety and Efficacy of Fluoroscopy-free Technique During Retrograde Intrarenal Surgery for Renal Stones: A Prospective, Randomized, Non-inferiority Trial

With improved flexible URS instrumentation and lithotripsy technology, retrograde intrarenal surgery (RIRS) became an alternative and excellent option for renal stones. Fluoroscopy imaging may be necessary during various steps of RIRS, such as insertion of a guidewire and stent, access sheath insertion, detection of stone location and size, and assessment of collecting system anatomy.

In an effort to decrease radiation exposure, several studies were conducted to evaluate the possibility of performing RIRS under direct visualization without fluoroscopy. Most studies concluded that fluoroscopy-free RIRS is a feasible, effective, and safe technique. The reported stone-free rate ranged from 83.8% to 95.7%. No major complications were observed.

Despite the reported high safety and efficacy of the fluoroscopy-free RIRS technique, most of the studies were retrospective and included only uncomplicated cases, and none of the studies address its results against control.

In the present study, the investigators will prospectively evaluate the efficacy and safety of fluoroscopy-free RIRS for renal stones in comparison with fluoroscopy-guided technique as standard control. The study will include all patients with renal stones amenable to RIRS. The investigators expected that the fluoroscopy-free technique can deal with large stones and complex situations with high safety and success rate. The study hypothesis is that "the fluoroscopy-free technique has efficacy and safety similar to the fluoroscopy-guided technique".

The investigators also aim to determine the patients and surgical characteristics impacting the need for fluoroscopy. The intra-operative fluoroscopy imaging is expected to be necessary during RIRS, especially in complicated cases. In the fluoroscopic-free group, the fluoroscopic equipment will be available in the operating room and will be used if needed.