Presented by: Catalina Solano MD
GRC n20, Groupe de Recherche Clinique sur la Lithiase Urinaire, Hôpital Tenon, Sorbonne Université

Introduction

In this study, our aim was to compare the efficiency of the thulium fiber laser (TFL), the holmium: yttrium–aluminum–garnet (Ho:YAG) laser, and the pulsed thulium:yttrium aluminum garnet laser (pTm: YAG) by evaluating the stone mass loss after lithotripsy using different lasers on BegoStones and human stones in an in vitro model.

Materials

Methods: We utilized a Ho:YAG laser (30 W; Rocamed), a TFL Drive (60W; Coloplast), and a pTm:YAG (100 W; THULIO Dornier) for our experiments. The laser parameters for TFL were set as follows: (10 W= 0.5 J x 20 Hz; short pulse). For Ho:YAG, we used (10 W= 0.5 J x 20 Hz), employing both short and long pulses. pTm:YAG was set at  (12.5 W= 0.6 J x 20 Hz, long pulse  and 0.5 J x 25Hz dusting). We performed contact lithotripsy on phantoms (BegoStones) and human stones with different compositions, including uric acid (UA) and calcium oxalate monohydrate (COM) in water environments. Laser ablation was carried out with a total energy of 3000 J. Mass loss was determined by calculating the difference between the initial phantom mass and the final ablated phantom mass for both phantoms and human stones.

Results

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The median mass loss for TFL laser configurations was 22 mg for uric acid (UA) stones and 36 mg for calcium oxalate monohydrate (COM) stones. For Ho:YAG, the median mass loss was 10 mg for UA stones and 24 mg for COM stones, while for p-Tm:YAG, it was 25 mg for UA stones and 24 mg for COM stones. Statistical analysis revealed a significant difference in ablated weight between TFL and Tm:YAG laser devices (p-value = 0.03) for UA stones (88 mg vs. 50 mg), whereas no significant difference was observed between Ho:YAG and TFL, or Ho:YAG and pTm:YAG lasers.

Conclusion

In our in vitro study, employing dusting settings, TFL lithotripsy demonstrated higher efficiency in terms of achieving greater mass loss compared to Ho:YAG and pTm:YAG lithotripsy.

Funding

none

Lead Authors

Fréderic Panthier, MD
GRC n20, Groupe de Recherche Clinique sur la Lithiase Urinaire, Hôpital Tenon, Sorbonne Université

Marie Chicaud, MD
Department of Urology, Limoges University Hospital

Luigi Candela, MD
Division of Experimental Oncology/Unit of Urology, URI-Urological Research Institute IRCCS Ospedale San Raffaele

Mariela Corrales, MD
GRC n20, Groupe de Recherche Clinique sur la Lithiase Urinaire, Hôpital Tenon, Sorbonne Université

Olivier Traxer, FACS
GRC n20, Groupe de Recherche Clinique sur la Lithiase Urinaire, Hôpital Tenon, Sorbonne Université, Service d'Urologie, Assistance-Publique Hôpitaux de Paris, Hôpital Tenon, Sorbonne Université,