In vivo porcine model for practicing retrograde intrarenal surgery

To examine the feasibility of retrograde intrarenal surgery (RIRS) in a porcine model.

Female pigs (n = 3) were placed in a dorsal lithotomy position under general anesthesia, and stone material was inserted into the renal pelvis of the pigs. The bladder was entered with a cystoscope, and a 0.038-inch hydrophilic guidewire was passed into the renal pelvis. Following successful placement of the guidewire, a ureteral access sheath (9.5/11.5 Fr) was placed to allow for optimal visualization. A 7.5-Fr flexible ureteroscope (Karl Storz Flex-X2) and a 200-μm laser fiber were used for lithotripsy. When basketing was deemed necessary, zero-tipped nitinol stone baskets were used. Trainees then practiced all these manipulations on the model.

Urologists with moderate experience in advanced endourologic surgery were trained using this model. However, there were some surgical difficulties due to the urinary system anatomy of the pig. Intravaginal location of the urethra, bladder neck location of the ureters, tight ureteric orifices, tortuous ureters, longitudinally elongated renal pelvis, narrow infundibulopelvic angle and shallow calices made the passage of the instruments and maneuverability of the flexible ureteroscope more difficult than in a human model.

Despite some difficulties, our porcine model was very effective, because all the trainees successfully practiced the RIRS manipulations on this model.