To develop a new technique for performing endoscopic combined intrarenal surgery in the prone split-leg position and to evaluate its efficacy using computed tomography.

Between December 2010 and January 2013, 60 patients with large calculi (39.2 ± 2.6 mm) underwent this surgery. A laser fiber was used with a flexible ureteroscope introduced through a ureteral access sheath, and lithoclast lithotripsy was performed through a mini-percutaneous tract. Three-dimensional computed tomography was performed to determine anatomic variations, including the ureteral location and ureteropelvic junction angle in all patients in both the supine and prone positions.

All procedures were performed successfully with a single tract and the patient in the prone split-leg position. The mean surgical time was 120.5 ± 6.7 min. The initial stone-free rate was 82%, and the final stone-free rate was 87% after further treatment. One patient required blood transfusion, but none had severe complications. Computed tomography showed that the ureter between the orifice and ureteropelvic junction was straighter and the ureteropelvic junction angle was significantly smaller for surgeries conducted in the prone position than the supine position.

Flexible ureteroscopy in the prone split-leg position is a viable technique. It allows easy insertion of the ureteral sheath and access of the ureteroscope to the renal pelvis. The findings suggest that this hybrid surgery is an efficient, effective, and versatile procedure for the management of renal calculi.