https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Fri, 05 Jun 2026 22:18:36 GMT 2026-06-05T22:18:36Z http://hdl.handle.net/10985/17642 Ho:YAG laser lithotripsy in non-contact mode: optimization of fiber to stone working distance to improve ablation efficiency DE CONINCK, Vincent; KELLER, Etienne Xavier; CHIRON, Paul; DRAGOS, Laurian B.; EMILIANI, Esteban; DOIZI, Steeve; BERTHE, Laurent; TRAXER, Olivier P. Purpose: To evaluate how variable working distances between the laser fiber and the stone influence ablation volume. Methods: A laser fiber was fixed on a robotic arm perpendicular to an artificial stone. A single laser pulse was triggered at different working distances (0–2.0 mm in 0.2 mm increments) between the distal fiber tip and the stone. To achieve a measurable impact, pulse energy was set to 2 and 3 J, with either short or long pulse duration. Ablation volume was calculated with an optical microscope. Experiments were repeated five times for each setting. Results: Highest ablation volume was observed with a long pulse of 3 J at a working distance of 0.4 mm between the laser fiber and the stone surface (p value < 0.05). At 2 J, the highest ablation volume was noticed with a short pulse in contact mode. However, ablation volume of the latter was not significantly greater than with a long pulse of 2 J at a working distance of 0.4 mm (p value > 0.05). Compared to lithotripsy in contact mode, triggering a single long pulse at 0.4 mm increased ablation volume by 81% (p value = 0.016) at 2 J and by 89% (p value = 0.034) at 3 J. Conclusions: For Ho:YAG laser lithotripsy, ablation volume may be higher in non-contact mode using long pulses, rather than in direct contact to the stone. Findings of the current study support the need of further studies of lithotripsy in non-contact mode. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/17642 2019-01-01T00:00:00Z DE CONINCK, Vincent KELLER, Etienne Xavier CHIRON, Paul DRAGOS, Laurian B. EMILIANI, Esteban DOIZI, Steeve BERTHE, Laurent TRAXER, Olivier P. Purpose: To evaluate how variable working distances between the laser fiber and the stone influence ablation volume. Methods: A laser fiber was fixed on a robotic arm perpendicular to an artificial stone. A single laser pulse was triggered at different working distances (0–2.0 mm in 0.2 mm increments) between the distal fiber tip and the stone. To achieve a measurable impact, pulse energy was set to 2 and 3 J, with either short or long pulse duration. Ablation volume was calculated with an optical microscope. Experiments were repeated five times for each setting. Results: Highest ablation volume was observed with a long pulse of 3 J at a working distance of 0.4 mm between the laser fiber and the stone surface (p value < 0.05). At 2 J, the highest ablation volume was noticed with a short pulse in contact mode. However, ablation volume of the latter was not significantly greater than with a long pulse of 2 J at a working distance of 0.4 mm (p value > 0.05). Compared to lithotripsy in contact mode, triggering a single long pulse at 0.4 mm increased ablation volume by 81% (p value = 0.016) at 2 J and by 89% (p value = 0.034) at 3 J. Conclusions: For Ho:YAG laser lithotripsy, ablation volume may be higher in non-contact mode using long pulses, rather than in direct contact to the stone. Findings of the current study support the need of further studies of lithotripsy in non-contact mode. http://hdl.handle.net/10985/15520 Impact of laser fiber tip cleavage on power output for ureteroscopy and stone treatment HADDAD, Mattieu; EMILIANI, Esteban; ROUCHAUSSE, Yann; COSTE, Frédéric; BERTHE, Laurent; DOIZI, Steeve; BUTTICÈ, Salvatore; SOMANI, Bhaskar Kumar; TRAXER, Olivier P. Purpose: Holmium:YAG laser is the most used laser for urolithiasis. Generally, we use metallic scissors to cut the fiber tip to restore its effectiveness. Many cleaving methods have been described to avoid fiber damage and to restore its greatest power to the fiber. There is a lack of information regarding which cleaving method should be used and its effect on the fiber. In order to compare these effects, we studied different cleavage methods in terms of power output and its effects on the fiber. Methods: New single-use 272-μm fibers were used with a holmium:YAG laser lithotripter. Five kinds of fiber tips were compared: a new intact fiber, cleaved with ceramic scissors, cleaved with metallic scissors, first cleaved then stripped and first stripped then cleaved. The fibers were used against synthetic stones (BegoStone ® ) similar to calcium oxalate monohydrate, with fragmentation (SP, 5 Hz, 1.5 J) and dusting (LP, 15 Hz, 0.5 J) settings. We measured power output at 0, 1, 5, 10 and 15 min. Results: For fragmentation parameters, there was a statistical difference between the 5 groups at 0 and 1 min of laser use (p < 0.05) and none for time period over 1 min (p = 0.077–0.658). For dusting parameters, there was a statistical difference between the 5 groups at 0 min of laser use (p < 0.05) and none for time period over 0 min (p = 0.064–1). Conclusion: Cleaving the fiber tip may restore its effectiveness to the fiber, but only for a limited time, although it may preserve the scopes from damage. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/15520 2017-01-01T00:00:00Z HADDAD, Mattieu EMILIANI, Esteban ROUCHAUSSE, Yann COSTE, Frédéric BERTHE, Laurent DOIZI, Steeve BUTTICÈ, Salvatore SOMANI, Bhaskar Kumar TRAXER, Olivier P. Purpose: Holmium:YAG laser is the most used laser for urolithiasis. Generally, we use metallic scissors to cut the fiber tip to restore its effectiveness. Many cleaving methods have been described to avoid fiber damage and to restore its greatest power to the fiber. There is a lack of information regarding which cleaving method should be used and its effect on the fiber. In order to compare these effects, we studied different cleavage methods in terms of power output and its effects on the fiber. Methods: New single-use 272-μm fibers were used with a holmium:YAG laser lithotripter. Five kinds of fiber tips were compared: a new intact fiber, cleaved with ceramic scissors, cleaved with metallic scissors, first cleaved then stripped and first stripped then cleaved. The fibers were used against synthetic stones (BegoStone ® ) similar to calcium oxalate monohydrate, with fragmentation (SP, 5 Hz, 1.5 J) and dusting (LP, 15 Hz, 0.5 J) settings. We measured power output at 0, 1, 5, 10 and 15 min. Results: For fragmentation parameters, there was a statistical difference between the 5 groups at 0 and 1 min of laser use (p < 0.05) and none for time period over 1 min (p = 0.077–0.658). For dusting parameters, there was a statistical difference between the 5 groups at 0 min of laser use (p < 0.05) and none for time period over 0 min (p = 0.064–1). Conclusion: Cleaving the fiber tip may restore its effectiveness to the fiber, but only for a limited time, although it may preserve the scopes from damage.