Urologists have no lack of new treatment options for stones, but sometimes the difference between the dozen or so Thulium fiber laser systems that have come to market since 2018 lies only in the graphical user interface. The actual capabilities and underlying technology are identical. This was one helpful piece of advice from Prof. Olivier Traxer (FR) during his state-of-the-art lecture “Beyond Holmium Laser: A new laser technology every year?”.
Prof. Traxer spoke at the Plenary Session on urinary stones on the final day of EAU23 in Milan. A core urological topic, the session covered a lot of ground, from medical to surgical treatment and the multidisciplinary approach that can come when urologists and nephrologists join forces in the analysis and treatment of kidney stones.
Traxer also cautioned the audience about the manufacturers’ presets on machines: a poll of some stone experts’ preferred settings for their thulium fibre systems shows no consensus at all, each having his or her own preferred presets. “As urologists we should also warn manufacturers to stop advertising the high frequencies that their products can achieve. This might work well in lab settings, but in real life we cannot maintain these high-frequency regimes on our patients.”
Distilling his lecture to three take-home messages, Prof. Traxer impressed on the audience the formula Energy x Frequency = Power, or J x Hz = Watts, emphasising the importance of energy and power, over frequency.
Second, when evaluating the effectiveness of new laser technology, the real-life application should be leading as laboratory settings cannot always be reproduced bedside. Finally, Prof. Traxer presented a useful rule of thumb for the audience: for kidney stones, work from surface to centre and always use 20-25W or less. For ureteral stones, from centre to surface and using a lower frequency range of 12-15W.
Dangers of overheating
Earlier in the session, Ass. Prof. Panagiotis Kallidonis (GR) and Dr. Thomas Tailly (BE) traded a few friendly barbs about the risk of overheating kidneys during the debate “Temperature rise by laser application: Fact or myth?”
With the possibilities of high-wattage machines, certainly the possibility and risk is very real. Combined with access sheaths, a manual pump and intermittent use of laser, power of 40W can safely be applied, argued Prof. Kallidonis. Dr. Tailly instead pointed that other than using more energy, there was very little evidence to suggest high-power use yielded better results than 10-20W. Chilled irrigation would be even better.
In the subsequent discussion, led by EULIS Chairman Prof. Christian Seitz (AT), the three discussed the impact of irrigation and how this could even best be measured in the first place, as well as proper use of sheaths.