Intrarenal pressure detection during flexible ureteroscopy with fiber optic pressure sensor system in porcine model

Abstract

To validate the feasibility of a fiber-optic pressure sensor-based pressure measurement device for monitoring intrarenal pressure and to analyze the effects of ureteral acess sheath (UAS) type, surgical location, perfusion flow rate, and measurement location on intrarenal pressure (IRP). The measurement deviations and response times to transient pressure changes were compared between a fiber-optic pressure sensing device and a urodynamic device IRP in an in vitro porcine kidney and in a water tank. Finally, pressure measurements were performed in anesthetized female pigs using fiber-optic pressure sensing device with different UAS, different perfusion flow rates, and different surgical positions at different renal calyces and ureteropelvic junctions (UPJ). According to our operation, the result is fiber optic pressure sensing devices are highly accurate and sensitive. Under the same conditions, IRP varied among different renal calyces and UPJ (P < 0.05). IRP was lowest at 50 ml/min and highest at 150 ml/min (P < 0.05). Surgical position had a significant effect on IRP (P < 0.05). 12/14 Fr UAS had a lower IRP than 11/13 Fr UAS. Therefore fiber optic pressure sensing devices are more advantageous for IRP measurements. In ureteroscopy, the type of ureteral sheath, the surgical position, the perfusion flow rate, and the location of the measurement all affect the intrarenal pressure value.

Keywords: Fiber-optic; Intrarenal pressure; Renal calyx; Surgical position; Ureteroscopy.

Figure 1

Pressure and response time detection of fiber optic pressure sensor and urodynamic pressure sensor [(A): Measured values of fiber-optic pressure sensors and urodynamic pressure sensors versus true values. (B): Response time of the urodynamic pressure sensor to a sudden change in pressure. (C): Response time of the fiber optic pressure sensor to a sudden change in pressure].

Figure 2

IRP in different types of UAS, surgical positions, irrigation flow rates, and intrarenal pressure measurement locations. [(A): IRP in different renal calyces with same surgical positions and same water flow velocities in 11/13 Fr UAS. (B): IRP in different water flow velocities with same surgical positions and different renal calyces 11/13 Fr UAS. (C): IRP in different water flow velocities with same surgical positions and different renal calyces 12/14 Fr UAS].

Figure 3

Visual fields of the same surgical position, the same intrarenal manometry position, and different water flow perfusion rates. [(A): 50 ml/min. (B): 100 ml/min. (C): 150 ml/min].

Figure 4

Experiments on precision and reaction time. [(A): Underwater pressure measurement at different depths. (B): Urodynamic instrument for pressure testing. (C): Conceptual diagram of a device for intrarenal pressure detection and control based on fiber optic pressure sensors. (D): Conceptual diagram of a pressure measurement device based on a fiber optic pressure sensor. (E): Isolated porcine kidney, ureter and bladder. (F): 12/14 Fr UAS (left) and 11/13 Fr UAS (right). (G): Fiber Optic Pressure Measurement System. (H): Fiber Optic Sensors for Pressure Measurement in the Kidney].

Figure 5

Surgical position [(A): Head-high-feet-low (15°), (B): Supine (0°), (C): Head-low-feet-high (10°)].