PD22-06 BENCH-TOP COMPARISON OF CONVENTIONAL BULLS-EYE, THE LASER DIRECT ALIGNMENT RADIATION REDUCTION TECHNIQUE AND A NOVEL LOW-RADIATION TARGETING NEEDLE TO REDUCE FLUOROSCOPY DURING PERCUTANEOUS RENAL ACCESS

Complete URS procedures were recorded and 30 stone fragments were extracted and measured using digital calipers. The novel software program was applied to the recorded URS footage in order to obtain ureteroscope-derived stone size measurements. These ureteroscope-derived measurements were then compared to the actual measured fragment size. RESULTS: The median longitudinal and transversal error was 0.14 mm (95%CI 0.1-0.18) and 0.09 mm (95%CI 0.02-0.15), respectively. The overall software accuracy and precision were 0.17 mm and 0.15 mm, respectively. The longitudinal and transversal measurements obtained by the software and digital calipers were highly correlated (r ¼ 0.97 and 0.93). Neither stone size nor stone type was correlated with error measurements. CONCLUSIONS: This novel method and software reliably measured stone fragment size during URS. The software ultimately has the potential to make ureteroscopy safer and more efficient. Figure 1. Method of stone measurement. (a, c) Stone fragment as measured by digital calipers. (b, d) The same stone as measured by software. The fragment is grasped within the basket and the basket tip serves as the reference point for stone measurement. A scale can be seen around the periphery of the image, with a 1 mm measurement marked in yellow. Stone can also be measured by selecting the limits of the stone (seen in green, with corresponding stone measurement of 4.11 and 1.82 mm).