Purpose The objective of this study is to evaluate the laser-tissue effects of laser radiation emitted by a newly developed high frequency pulsed Tm:YAG laser in comparison to the continuous wave Tm:YAG laser and the pulsed Ho:YAG laser. Methods Ex-vivo experiments were performed on freshly slaughtered porcine kidneys in a physiological saline solution. Experiments were performed using two different laser devices in different settings: A Tm:YAG laser was operated in a pulsed mode up to 300 Hz and in a continuous wave (CW) mode. Results were compared with a 100 W standard pulsed Ho:YAG laser system. Comparative tissue experiments were performed at 5 W, 40 W and 80 W. The incision depth and the laser damage zone were measured under a microscope using a calibrated ocular scale. Results Increased laser power resulted in increased incision depth and increased laser damage zone for all investigated lasers in this set-up. The Ho:YAG created the largest combined tissue effect at the 5 W power setting and seems to be the least controllable laser at low power for soft tissue incisions. The CW Tm:YAG did not incise at all at 5 W, but created the largest laser damage zone. For the new pulsed Tm:YAG laser the tissue effect grew evenly with increasing power. Conclusion Among the investigated laser systems in this setting the pulsed Tm:YAG laser shows the most controllable behavior, insofar as both the incision depth and the laser damage zone increase evenly with increasing laser power.
The understanding of tissue damage by laser radiation is very important for the safety in the application of surgical lasers. The objective of this study is to evaluate cutting, vaporization and coagulation properties of the 2 µm Tm:YAG laser (LISA Laser Products OHG, GER) in comparison to the 2.1 µm Ho:YAG laser (Coherent Medical Group, USA) at different laser power settings in an in vitro model of freshly harvested porcine kidneys. Laser radiation of both laser generators was delivered by using a laser fiber with an optical core diameter of 550 µm (RigiFib, LISA Laser GER). Freshly harvested porcine kidneys were used as tissue model. Experiments were either performed in ambient air or in aqueous saline. The Tm:YAG laser was adjusted to 5 W for low and 120 W for the high power setting. The Ho:YAG laser was adjusted to 0.5 J and 10 Hz (5 W average power) for low power setting and to 2.0 J and 40 Hz (80 W average power) for high power setting, accordingly. The specimens of the cutting experiments were fixed in 4 % formalin, embedded in paraffin and stained with Toluidin blue. The laser damage zone was measured under microscope as the main evaluation criteria. Laser damage zone consists of an outer coagulation zone plus a further necrotic zone. In the ambient air experiments the laser damage zone for the low power setting was 745 ± 119 µm for the Tm:YAG and 614 ± 187 µm for the Ho:YAG laser. On the high power setting, the damage zone was 760 ± 167 µm for Tm:YAG and 715 ± 142 µm for Ho:YAG. The incision depth in ambient air on the low power setting was 346 ± 199 µm for Tm:YAG, 118 ± 119 µm for Ho:YAG. On the high power setting incision depth was 5083 ± 144 µm (Tm:YAG) and 1126 ± 383 µm (Ho:YAG) respectively. In the saline solution experiments, the laser damage zone was 550 ± 137 µm (Tm:YAG) versus 447 ± 65 µm (Ho:YAG), on the low power setting and 653 ± 137 µm (Tm:YAG) versus 677 ± 134 µm (Ho:YAG) on the high power setting. Incision depth was 1214 ± 888 µm for Ho:YAG whereas Tm:YAG did not cut tissue at 5 W in saline solution. On the high power setting, the incision depth was 4050 ± 1058 µm for Tm:YAG and 4083 ± 520 µm for Ho:YAG. Both lasers create similar laser damage zones of <1 mm in ambient air and in saline solution. These in vitro experiments correspond well with in vivo experiments. Thereby, Tm:YAG offers a cutting performance, coagulation and safety profile similar to the standard Ho:YAG lasers in urological surgery.
Miniaturization and attending developments such as ultrasonographic-guided puncture, single step dilatation of the tract, low irrigation pressure in open systems and a tubeless procedure lead to lower complication rates in PCNL. All of the established procedures have their own range of indication with regard to size and location of the stone. They amplified the possibility of a customized therapy for each patient.
Zusammenfassung Hintergrund In den letzten Jahren wurde die Entwicklung miniaturisierter Amplatz-Schäfte für die perkutane Nephrolitholapaxie mit dem Ziel eines verringerten Nierentraumas vorangetrieben. Bisherige Studien konnten zwar vergleichbar gute Steinfreiheitsraten im Vergleich zur herkömmlichen PNL bestätigen, jedoch zeigten sich ebenfalls vergleichbare Häufigkeiten postoperativen Fiebers bzw. Septikämien. Als mögliche Ursache hierfür wird der Einfluss der intraoperativen intrapelvinen Drücke aufgrund verwendeter Spülung diskutiert. Ziel der vorliegenden Ex-vivo-Studie war der Vergleich der intrapelvinen Druckverhältnisse unter Verwendung der miniaturisierten 9,5 Ch- bzw. 12 Ch-Amplatz-Schäfte mit dem bereits voruntersuchten 17,5 Ch-MIP M-Schaft. Material und Methoden Die Schäfte wurden an einem perfundierten Schweinenierenmodell frisch geschlachteter Schweine unter verschiedenen Perfusionsdrücken evaluiert. Der Spüldruck wurde zum einen über eine Spülpumpe (Uromat E.A.S.I. Pumpe, Karl Storz, Tuttlingen, Deutschland) oder per Schwerkraft erzeugt. Über einen transparenchymatös eingebrachten Urodynamikkatheter konnte der intrapelvine Druck kontinuierlich gemessen werden. Es wurden zusätzliche Analysen mit aktiver Flüssigkeitsabsaugung über einen einliegenden Ureterkatheter durchgeführt. Ergebnisse Der intrapelvine Druck stieg in den Messungen mit moderaten Spüldruckverhältnissen sowohl durch Spülpumpe als auch durch Schwerkraft für beide Schaftgrößen nicht über 40 cmH2O (entsprechend 30 mmHg). Unter Verwendung einer aktiven Flüssigkeitsabsaugung konnten keine bemerkenswerten Druckunterschiede detektiert werden. Bei sehr hohen Spüldrücken konnte sowohl bei Verwendung der Spülpumpe als auch für die Spülung mit Schwerkraft ein deutlicher Anstieg der intrapelvinen Druckverhältnisse unter Verwendung des 9,5 Ch-Schaftes nachgewiesen werden. Schlussfolgerungen Beide miniaturisierten MIP-Schäfte können mit vergleichbar günstigen Druckeigenschaften wie das etablierte 17,5 Ch-MIP-Set aufwarten. Trotz deutlicher Reduzierung des Schaftdurchmessers bleibt der intrapelvine Druck bei moderaten Spüldrücken unter 40 cmH2O und somit im nicht bedenklichen Bereich.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.