A novel 7.5 single-use flexible ureteroscope with in-built temperature and pressure sensors: Is there a limit to reliability and safety? An in vivo experimental study.

OBJECTIVE

To evaluate the reliability of the intrarenal fluid temperature (IFT) and intrarenal pressure (IRP) fluctuations using a 7.5 Fr single-use ureteroscope with temperature and pressure sensors and ureteral access sheath (UAS) in an in vivo porcine model.

METHODS

Two female pigs underwent flexible ureteroscopy using a 150 W Ho: YAG laser with a 200 μm fiber. The energy settings varied from 10 W to 60 W. A thermocouple was used for the documentation of IFT and a pressure sensor was used for the documentation of IRP, while the laser was activated for 30 s, without interruption, per trial. Twenty trials were performed per kidney unit. The recordings conducted by the scope's sensors were evaluated in comparison to the external recordings. The value of 43 °C was considered to be the temperature upper limit threshold, and the value of 30 mmHg was set as the pressure safety limit. The correlation of the recorded data was the primary endpoint of the study. The IRP and IFT elevations were considered the secondary endpoint.

RESULTS

Overall, 40 measurements were conducted. The correlation between the conventional and scope's measurements was statistically significant in both IRP and IFT settings. Pearson's scores varied from 0.967 to 0.993 with p < 0.001. Despite the fact that IFT elevation was directly associated with laser activation, the tissue damage threshold was not reached across all experimental trials. The same observation was performed regarding the pressure control.

CONCLUSION

This in vivo experimental study demonstrated that high-power Ho: YAG lithotripsy with the novel 7.5 Fr single-use ureteroscope with sensors is safe and feasible, while allowing a reliable and close monitoring of the major safety factors.