The impact of siphoning effect on renal pelvis pressure during ureteroscopy using an in vitro kidney and ureter model.

Purpose: To experimentally measure renal pelvis pressure (P) in an ureteroscopic model when applying a simple hydrodynamic principle, the siphoning effect.

Methods: A 9.5Fr disposable ureteroscope was inserted into a silicone kidney-ureter model with its tip positioned at the renal pelvis.

Effect of outflow resistance on intrarenal pressure at different irrigation rates during ureteroscopy: in vivo evaluation.

To maintain visualization and control temperature elevation during ureteroscopy, higher irrigation rates are necessary, but this can increase intrarenal pressure (IRP) and lead to adverse effects like sepsis. The IRP is also dependent on outflow resistance but this has not been quantitatively evaluated in a biological system. In this study, we sought to characterize the IRP as a function of irrigation rate in an in vivo porcine model at different outflow resistances.

Thermal Safety Boundaries for Laser Power and Irrigation Rate During Ureteroscopy: In Vivo Porcine Assessment With a Ho:YAG Laser.

Objective: To map thermal safety boundaries during ureteroscopy (URS) with laser activation in two in vivo porcine subjects to better understand the interplay between laser power, irrigation rate, and fluid temperature in the collecting system.

Methods: URS was performed in two in vivo porcine subjects with a prototype ureteroscope containing a thermocouple at its tip. Up to 6 trials of 60 seconds laser activation were carried out at each selected power setting and irrigation rate.

Quantification of outflow resistance for ureteral drainage devices used during ureteroscopy.

Purpose: Since renal pelvis pressure is directly related to irrigation flowrate and outflow resistance, knowledge of outflow resistance associated with commonly used drainage devices could help guide the selection of the type and size of ureteral access sheath or catheter for individual ureteroscopic cases. This study aims to quantitatively measure outflow resistance for different drainage devices utilized during ureteroscopy.

Methods: With measured irrigation flowrate and renal pelvis pressure, outflow resistance was calculated using a hydrodynamic formula.

Gender Disparities and Differences Among Urologists Included in Top Doctor Lists.

Objective: To understand gender trends among urologists included in "Top Doctor" lists as more women practice urology, we (1) Evaluated whether Top Doctor lists reflect a contemporary distribution of urologists by gender; (2) Describe regional differences in gender composition of lists; (3) Report similarities and differences among men and women Top Doctors.

Methods: All urologists in regional Top Doctor Castle Connolly lists published in magazines between January 1, 2020 and June 22, 2021 were included. Physician attributes were abstracted.

Laser Heating of Fluid With and Without Stone Ablation: Assessment.

Laser lithotripsy can cause excessive heating of fluid within the collecting system and lead to tissue damage. To better understand this effect, it is important to determine the percentage of applied laser energy that is converted to heat and the percentage used for stone ablation. Our objective was to calculate the percentage of laser energy used for stone ablation based on the difference in fluid temperature measured in an model when the laser was activated without and with stone ablation.

Characterization of Fluid Dynamics and Temperature Profiles During Ureteroscopy with Laser Activation in a Model Ureter.

Ureteral thermal injury has been reported in patients following ureteroscopy with laser lithotripsy due to overheating of fluid within the ureter. Proper understanding of this risk necessitates knowing the volume of fluid available to absorb laser energy. This can be approximated as the volume of fluid that mixes during laser activation, since energy transfer through fluid is dominated by convection.

Laser operator duty cycle effect on temperature and thermal dose: in-vitro study.

Purpose: High-power laser lithotripsy can elevate temperature within the urinary collecting system and increase risk of thermal injury. Temperature elevation is dependent on power settings and operator duty cycle (ODC)-the percentage of time the laser pedal is depressed. The objective of this study was to quantify temperature and thermal dose resulting from laser activation at different ODC in an in-vitro model.