Eight stone patients underwent flexible ureteroscopy with a dual lumen ureteroscope. A Verrata pressure guide wire (Phillips Volcano) was passed through the working channel of the scope while irrigation pressure was maintained at 150mmHg through the second channel. Pressure measurements were taken both with and without a ureteral access sheath. Retrograde pyelography images were used to measure infundibular widths.
As seen in the table below, the mean widths of the upper pole, middle, and lower pole major infundibulae were 9.1mm, 6.4 mm, and 9.5 mm, respectively. Dr. Patel and his team found that the intracalyceal pressure was lower in each region of the kidney when a ureteral access sheath was used. Additionally, using a 16Fr access resulted in the lowest intracalyceal pressures measured in all regions of the kidney.
Dr. Patel concluded that based on these results intracalyceal pressure is lower when a ureteral access sheath is utilized during flexible ureteroscopy. He also added that larger access sheaths provide the lowest intracalyceal pressure.
At the conclusion of his presentation, Dr. Patel was asked by members of the audience about the renal sheath location, the type of irrigation used, and the distance of the tip of the pressure wire from each calyx. Dr. Patel answered that for this study the sheath was deployed into the renal pelvis and that a distance of 3mm was used for the pressure wire. For irrigation, both a hand pump and an automated pump maintained at 150 mmhg was used.
Presented by Roshan Patel, MD, Assistant Clinical Professor, University of California, Irvine, Department of Urology
Co-Authors: Michael Owyong, ML Ayad, Martin Hofmann, Jaime Landman, Professor and Chair, Ralph V. Clayman, Professor, University of California, Irvine, Department of Urology
Written by Renai Yoon, Department of Urology, University of California-Irvine, medical writer for UroToday.com at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France