Esteban Emiliani1, Michele Talso2, Sung-Yong Cho3, Mohammed Baghdadi2, Sadam Mahmoud2, Hugo Pinheiro2, Olivier Traxer4. 1. Department of Urology, Tenon Hospital, Université Paris VI, Pierre et Marie Curie, Paris, France; Group Recherche Clinique Lithiase, Université Paris VI, Pierre et Marie Curie, Paris, France; Fundación Puigvert, Department of Urology, Universidad Autonoma de Barcelona, Barcelona, Spain. 2. Department of Urology, Tenon Hospital, Université Paris VI, Pierre et Marie Curie, Paris, France. 3. Boramae Medical Center, Department of Urology, Seoul Metropolitan Government-Seoul National University, Seoul, Republic of Korea. 4. Department of Urology, Tenon Hospital, Université Paris VI, Pierre et Marie Curie, Paris, France; Group Recherche Clinique Lithiase, Université Paris VI, Pierre et Marie Curie, Paris, France. Electronic address: olivier.traxer@tnn.aphp.fr.
Abstract
PURPOSE: The purpose of this study was to evaluate the popcorn technique using a wide range of holmium laser settings and fiber sizes in a systematic in vitro assessment. MATERIALS AND METHODS: Evaluations were done with 4 artificial stones in a collection tube. A fixed ureteroscope was inserted through a ureteral access sheath to provide constant irrigation flow and the laser was placed 1 mm from the bottom. Combinations of 0.5 to 1.5 J, 10 to 20 and 40 Hz, and long and short pulses were tested for 2 and 4 minutes. We used 273 and 365 μm laser fibers. All tests were repeated 3 times. The stones were weighed before and after the experiments to evaluate the setting efficiency. Significant predictors of a highly efficient technique were assessed. RESULTS: A total of 144 tests were performed. Mean starting weight of the stones was 0.23 gm, which was consistent among the groups. After the experiment the median weight difference was 0.07 gm (range 0.01 to 0.24). When designating a 50% reduction in stone volume as the threshold indicating high efficiency, the significant predictors of an efficient popcorn technique were a long pulse (OR 2.7, 95% CI 1.05-7.15), a longer duration (OR 11.4, 95% CI 3.88-33.29), a small (273 μm) laser fiber (OR 0.23, 95% CI 0.08-0.70) and higher power (W) (OR 1.14, 95% CI 1.09-1.20). CONCLUSIONS: Higher energy, a longer pulse, frequencies higher than 10 Hz, a longer duration and a smaller laser fiber predict a popcorn technique that is more efficient at reducing stone volume.
PURPOSE: The purpose of this study was to evaluate the popcorn technique using a wide range of holmium laser settings and fiber sizes in a systematic in vitro assessment. MATERIALS AND METHODS: Evaluations were done with 4 artificial stones in a collection tube. A fixed ureteroscope was inserted through a ureteral access sheath to provide constant irrigation flow and the laser was placed 1 mm from the bottom. Combinations of 0.5 to 1.5 J, 10 to 20 and 40 Hz, and long and short pulses were tested for 2 and 4 minutes. We used 273 and 365 μm laser fibers. All tests were repeated 3 times. The stones were weighed before and after the experiments to evaluate the setting efficiency. Significant predictors of a highly efficient technique were assessed. RESULTS: A total of 144 tests were performed. Mean starting weight of the stones was 0.23 gm, which was consistent among the groups. After the experiment the median weight difference was 0.07 gm (range 0.01 to 0.24). When designating a 50% reduction in stone volume as the threshold indicating high efficiency, the significant predictors of an efficient popcorn technique were a long pulse (OR 2.7, 95% CI 1.05-7.15), a longer duration (OR 11.4, 95% CI 3.88-33.29), a small (273 μm) laser fiber (OR 0.23, 95% CI 0.08-0.70) and higher power (W) (OR 1.14, 95% CI 1.09-1.20). CONCLUSIONS: Higher energy, a longer pulse, frequencies higher than 10 Hz, a longer duration and a smaller laser fiber predict a popcorn technique that is more efficient at reducing stone volume.
Authors: Jonathan S Ellison; Brian MacConaghy; Timothy L Hall; William W Roberts; Adam D Maxwell Journal: J Pediatr Urol Date: 2020-07-17 Impact factor: 1.830