Ex Vivo Evaluation of a Simulated Continuous Flow Ureteroscope Design "Presentation" - Aymon Ali
September 13, 2025
At the World Congress of Endourology and Uro-Technology, Aymon Ali from UC Irvine presented research on a simulated continuous flow ureteroscope designed to address dangerous intrarenal pressure elevations during retrograde intrarenal surgery that can cause complications like pyelovenous backflow and urosepsis. The team developed a prototype with separate inflow and outflow channels, testing it on ex vivo porcine kidneys and finding that intrarenal pressures consistently remained below the critical 40 cm water safety threshold across all conditions.
Biographies:
Aymon Ali, MD, Endourology Fellow, Department of Urology, University of California, Irvine, Orange, CA
Biographies:
Aymon Ali, MD, Endourology Fellow, Department of Urology, University of California, Irvine, Orange, CA
Read the Full Video Transcript
Aymon Ali: Good morning, everyone. My name is Aymon Ali. I'm an Endourology Fellow at the University of California, Irvine, and today I will be presenting our evaluation of a simulated continuous flow ureteroscope and its effect on intrarenal pressure during ex vivo porcine retrograde intrarenal surgery.
Traditional retrograde intrarenal surgery uses a single direction irrigation system, which may cause sustained increases in intrarenal pressure. Elevated IRP can result in pyelovenous backflow, urosepsis and renal injury. We aim to evaluate whether a continuous flow ureteroscope with separate inflow and outflow channels could maintain IRP below a 40 cm of water safety threshold. This threshold has been associated with an increased risk of renal injury.
To describe our methods, we assembled a simulated multichannel continuous flow ureteroscope using two small inflow channels and a larger 2 mm outflow port for aspiration. Intrarenal pressure was measured using a SENCTRL™ transducer placed in the renal pelvis of an ex vivo porcine kidney. We tested multiple irrigation pressures, two scope lengths, and different inflow and outflow configurations with each condition performed in triplicate.
This image shows our ex vivo model, including the simulated ureteroscope, porcine kidney, and pressure monitoring system.
Our results demonstrated that, across all settings, mean intrarenal pressures stayed well below the 40 cm of water threshold. The highest pressures occurred at maximum irrigant height and pressure when inflow is maximized and outflow is reduced as expected. Importantly, under typical operative settings, IRP often approached zero.
In conclusion, our simulated continuous flow ureteroscope with a large aspiration port maintained intrarenal pressures below 40 cm of water in all tested conditions. This does provide an opportunity to reduce pressure-associated complications during ureteroscopy, particularly in relation to flexible and navigable sheaths in aspiration ureteroscopes. Our next step is to validate these findings in vivo. Thank you.
Aymon Ali: Good morning, everyone. My name is Aymon Ali. I'm an Endourology Fellow at the University of California, Irvine, and today I will be presenting our evaluation of a simulated continuous flow ureteroscope and its effect on intrarenal pressure during ex vivo porcine retrograde intrarenal surgery.
Traditional retrograde intrarenal surgery uses a single direction irrigation system, which may cause sustained increases in intrarenal pressure. Elevated IRP can result in pyelovenous backflow, urosepsis and renal injury. We aim to evaluate whether a continuous flow ureteroscope with separate inflow and outflow channels could maintain IRP below a 40 cm of water safety threshold. This threshold has been associated with an increased risk of renal injury.
To describe our methods, we assembled a simulated multichannel continuous flow ureteroscope using two small inflow channels and a larger 2 mm outflow port for aspiration. Intrarenal pressure was measured using a SENCTRL™ transducer placed in the renal pelvis of an ex vivo porcine kidney. We tested multiple irrigation pressures, two scope lengths, and different inflow and outflow configurations with each condition performed in triplicate.
This image shows our ex vivo model, including the simulated ureteroscope, porcine kidney, and pressure monitoring system.
Our results demonstrated that, across all settings, mean intrarenal pressures stayed well below the 40 cm of water threshold. The highest pressures occurred at maximum irrigant height and pressure when inflow is maximized and outflow is reduced as expected. Importantly, under typical operative settings, IRP often approached zero.
In conclusion, our simulated continuous flow ureteroscope with a large aspiration port maintained intrarenal pressures below 40 cm of water in all tested conditions. This does provide an opportunity to reduce pressure-associated complications during ureteroscopy, particularly in relation to flexible and navigable sheaths in aspiration ureteroscopes. Our next step is to validate these findings in vivo. Thank you.