RIRS Versus ESWL for the Treatment of Renal Stones

Retrograde Intrarenal Surgery (RIRS) Versus Extracorporeal Shock Waves Lithotripsy (ESWL) for the Treatment of Renal Stones Measuring 6-20 mm: A Prospective Randomized Study

To evaluate the effectiveness of RIRS (retrograde intrarenal surgery) and ESWL (extracorporeal shockwaves lithotripsy) in the treatment of renal stone ranging form 6 to 20 mm size.

European urological guidelines consider RIRS and ESWL the treatments of choice for renal stones < 20 mm. RIRS is a endoscopic surgery which allows to rich the kidney from the ureter. A flexible ureteroscope is used for these kind of procedure. Through this device a laser fiber (Holmium laser) is used to treat the stones. After that, small fragments can be removed with a basket. In some cases, according to intraoperative findings, a ureteral stent can be push in the kidney to help the drainage of the kidney. ESWL is a procedure which allows to treat the stones by shock waves generated by a specific machine which work in direct contact with the skin of the patients (extracorporeal). Shockwaves pass all the tissues and finally reach the stones. Such energy allows to break the stones in small fragments, that wll be spontaneously passed by the patients. Specific parameters of these treatments are discussed in "Arms and Interventions". Many studies demonstrated high success rate of RIRS and this technique is becoming more and more adopt. One study demonstrated better outcomes of RIRS versus ESWL, but only for renal stones located in the inferior calices and smaller then 10 mm. There are not other studies comparing the two procedures and there are not proofs that RIRS ensures better outcomes for other renal stones (neither for size nor for location).

In the first arm (RIRS) the patients will be treated by a standard retrograde ureterorenoscopy and Holmium laser lithotripsy. Preoperative exams will be abdomen ultrasound and Xray (CT in case of stones > 15 mm), urine analysis and culture (according to all the more recent guidelines). Surgeries will be performed under general or spinal anesthesia, according to anesthesiologist evaluation. According with standard technique, ureteroscopy will be performed using both rigid and flexible ureteroscope. Lithotripsy will be performed by Holmium laser. Major stone fragments will be removed at the end of the procedure. Finally a double J ureteral stent will be push in specific cases depending on intraoperative findings (length of the procedure, macroscopic view of the ureter, residual stones etc.). RIRS will be an outpatients procedure with an hospital stay <23 hours. Some patients may require a longer hospital stay due to specific pre-operative diseases or intra/post-operative events.

In the second arm (ESWL) the patients will be treated by a standard extracorporeal shock waves lithotripsy (ESWL). Preoperative exams will be the same as first arm. No general or spinal anaesthesia will be used, but just intravenous medications if required. Ultrasound and/or X-Ray will be used to locate the stone. Power and number of shock waves will consist in 20-24 KV and 3000-3500 sw respectively, according to individual tolerance. ESWL will be an outpatients procedure with an hospital stay <23 hours. Some patients may require a longer hospital stay due to specific pre-operative diseases or intra/post-operative events.

Inclusion Criteria: renal stone measuring 6 to 20 mm signing informed consent WHO performance status 0-2 Exclusion Criteria: Other stone >5 mm concomitant ureteral stones BMI > 35 severe coagulopathy impossibility to sign informed consent pregnancy age < 18 years old or > 85

Bosio A, Alessandria E, Dalmasso E, Agosti S, Vitiello F, Vercelli E, Bisconti A, Gontero P. Flexible Ureterorenoscopy Versus Shockwave Lithotripsy for Kidney Stones </=2 cm: A Randomized Controlled Trial. Eur Urol Focus. 2022 Nov;8(6):1816-1822. doi: 10.1016/j.euf.2022.04.004. Epub 2022 Apr 22.