Effect of Laser Insult on Devices Used to Prevent Stone Retropulsion During Ureteroscopic Lithotripsy

Abstract

To examine laser damage to three commercially available devices used to prevent stone retropulsion during ureteroscopic lithotripsy. Two experiments were performed with 5 Accordion (Percsys, Palo Alto, CA), Stone Cone (Boston Scientific, Natick, MA), and NTrap (Cook Urological, Bloomington, IN) devices each. All devices were of 7-mm outer diameter. The holmium:YAG laser was set at 8 W. Experiment 1 was performed in an acrylic tube of 10-mm inner diameter in a saline water bath. The laser was fired against the antiretropulsion element of each device until the device could not be opened or closed. Experiment 2 was performed in a saline water bath; the laser was fired against the carrying catheter of each device until it was severed. For Experiment 1, the mean number of laser firings against the antiretropulsion element until device failure was 2 for the NTrap, and 28.6 for the Stone Cone. The Accordion was operable after 100 laser firings. The Accordion was more laser-resistant than either device (P < 0.001, P < 0.001, respectively), and the Stone Cone was more laser-resistant than the NTrap (P < 0.001). In Experiment 2, mean time to break the carrying catheter was 13.6 seconds for the NTrap, 17.4 seconds for the Stone Cone, and 6.6 seconds for the Accordion. The Stone Cone and NTrap carrying catheters were more laser-resistant than the Accordion (P = 0.007, P = 0.03, respectively) and there was no statistical difference between the Stone Cone and NTrap. The antiretropulsion element of the Accordion was most laser-resistant, and both the Accordion and Stone Cone antiretropulsion elements were more laser-resistant than the NTrap. The carrying catheters of the Stone Cone and NTrap had similar laser resistance, and both were more laser-resistant than the Accordion. Urologists should be mindful of structural characteristics when using these devices.