Presentation Authors: Roshan Patel*, Kamaljot Kaler, Mitchell O'Leary, Vinay Cooper, Egor Parkhomenko, Orange, CA, David Regan, Nashua, NH, Jaime Landman, Ralph Clayman, Orange, CA
Introduction: Detailed knowledge of forniceal and papillary blood flow would be helpful in determining the least vascular site for the placement of a nephrostomy track for percutaneous stone removal. Herein, we provide the first report regarding in vivo porcine renal forniceal and papillary blood flow at the level of the urothelium.
Methods: A Doppler transducer (Vascular Technology Inc.) with a 1 cm depth of penetration was mounted to a 3F, 120 cm catheter; the catheter was passed through the working channel of a flexible ureteroscope (Figure 1A, 1B and 1C). Retrograde nephroscopy was performed based on the retrograde pyelogram (Figure 1D) in six female Yorkshire pigs. Blood flow was mapped at the 12, 3, 6, and 9 o&[prime]clock forniceal positions and at the center of the papilla for all calyces. A 365-micron holmium laser fiber was then fired at 1.0J and 10Hz until it penetrated 1cm into the urothelium in order to further assess the accuracy of the Doppler probe reading.
Results: An audible signal was produced when the Doppler transducer was placed upon an area of the fornix where there was blood flow within 1 cm of the urothelium. Each reading was categorized from 0 (no flow) to 3 (high flow). A 3D reconstruction was created of the upper pole, interpolar, and lower pole posterior calyces (Figure 2). Laser entry into high flow areas resulted in increased bleeding times when compared to areas of low flow (p=0.01). Distribution of blood flow did not differ significantly between anterior and posterior calyces (p=0.475) nor along the length of the kidney (p=0.78). The 6 o&[prime]clock forniceal position had significantly more flow than the other forniceal locations (p=0.03). The center of each papilla consistently had significantly less blood flow (p < 0.001) than the forniceal locations.
Conclusions: A novel 3F Doppler transducer successfully mapped porcine calyceal blood flow. The least vascular area of the porcine kidney appears to be the center of the papilla; the most vascular area was along the fornix at 6 o&[prime]clock.