Presentation Authors: Roshan Patel*, Michael Owyong, Maged Ayad, Martin Hofmann, Jaime Landman, Ralph Clayman, Orange, CA
Introduction: Pyelovenous backflow created by elevated intrarenal pressures may lead to increased risk of bacteremia and sepsis during ureteroscopy. Herein, we provide the first report of intracalyceal pressures during flexible ureteroscopy utilizing a cardiac pressure guide wire.
Methods: Eight nephrolithiasis patients (2 male/6 female), with a mean age of 58.1 (Â±11.3) years underwent retrograde pyelography at the time of ureteroscopy. A 185 cm long, 1Fr Verrata pressure guide wire (Phillips Volcano Corporation, Amsterdam, Netherlands) was passed through the working channel of a 9.9Fr dual lumen flexible ureteroscope (Richard Wolf USA, Vernon Hills, IL) (Figure 1A); the irrigation pressure was maintained at 150mmHg through the second channel. The pressure guide wire was extended 1 cm beyond the tip of the ureteroscope; pressure measurements were recorded in the upper pole, interpolar, and lower pole calyces (Figure 1B) with and without a ureteral access sheath in place. Infundibular widths were measured with Vitrea software (Vital Images, Minnetonka, Minnesota).
Results: The mean (Â± SD) widths of the upper pole, interpolar, and lower pole major infundibulae were 9.1 (Â± 5.3) mm, 6.4 (Â± 3.1) mm, and 9.5 (Â± 3.4) mm, respectively. The ureteral access sheath was 14Fr (3 cases) and 16Fr (5 cases). The calyceal pressure was lower in each region of the kidney when a ureteral access sheath was used (Table 1). When the access sheaths were sub stratified based on sheath sizes, using a 16Fr access sheath resulted in the lowest calyceal pressures in all regions of the kidney (Table 1).
Conclusions: Calyceal pressure is lower when a ureteral access sheath is utilized during flexible ureteroscopy; the larger access sheaths provide lower calyceal pressure thereby reducing the risk of renal backflow.