Small diameter, actively deflectable, flexible ureteropyeloscopy

Abstract

Purpose: We studied and developed ureteroscopic technique and instrumentation beyond our initial experience with small diameter, actively deflectable, flexible ureteropyeloscopy.

Materials and methods: Flexible ureteropyeloscopy was performed at 2 university centers in 492 consecutive patients. Endoscope designs and development were based on strict specifications, including 8F or less tip diameter, 3.6F or greater working channel, 2-way active tip deflection and secondary deflection for lower pole intrarenal access. Flexible ureteroscopes manufactured by 5 companies were studied through various prototypic steps and surgical technique. Complementary accessories were developed for specific treatments, including endoscopic lithotripsy, management of urothelial lesions, treatment of upper urinary tract obstruction (that is strictures) and percutaneous access with ureteroscopic assistance in select complex cases.

Results: A total of 584 procedures were performed with the small diameter, actively deflectable, flexible ureteroscopes. Flexible ureteropyeloscopic access was always preformed over a working guide wire without an operative sheath. In addition, the 10F dual lumen catheter was the primary device used to obtain 2 guide wires (working and safety), and gently and minimally dilate the intramural segment. Larger dilators were required in only 12% of procedures. The entire intrarenal collecting system was accessed in 94% of cases with lower pole access requiring secondary or passive deflection in 60% of procedures. Endoscopic lithotripsy was the most common procedure performed in this series (303, 52%). Small diameter, flexible ureteroscopy and holmium laser lithotripsy were successful in 97% of patients with ureteral and 79% with intrarenal calculi. When a 2-stage ureteropyeloscopy procedure was used for large upper urinary tract calculi, the success rate for intrarenal calculi increased to 91%. Endoscopic biopsy and treatment of upper urinary tract transitional cell carcinoma were performed in 101 procedures (17%), while retrograde ureteroscopic incision for stricture disease was performed in 36 (6%). The overall major complication rate was less than 1% and there were no ureteral perforations, avulsions, sepsis or deaths. These new endoscopes were more fragile than larger predecessors but a maximum of 30 procedures were performed between interval repair.

Conclusions: Small diameter, actively deflectable, flexible ureteropyeloscopy facilitates various minimally invasive endoscopic therapies. Although this class of endoscope has greater fragility, it is easy to use and has broadened the therapeutic range of ureteroscopic treatment to include intrarenal lesions.