V01-09: SuperPulse Thulium fiber laser for lithotripsy of large renal stones: initial experience
The SuperPulse Thulium fiber laser may present as a valuable alternative to Holmium laser for lithotripsy. Its operating wavelength is closer to a major water absorption peak, which results in a higher ablation efficiency at low pulse energy compared to Holmium lithotripsy. Pulsed energy can be delivered through silica fibers as small as 50 microns, which may allow for miniaturization of the endourological instruments. Also, pulse shape can easily be modulated, because the Thulium fiber laser is pumped by a diode laser, which in turn can be electronically modulated to adapt its temporal beam profile. In this video we present the applicability of Thulium fiber laser for lithotripsy of large renal stones.
Three cases were operated by flexible ureteroscopy for large renal stones with a SuperPulse Thulium fiber laser generator at the Federal Medical-Biological Agency of Russian Federation State Institute of Continuous Medical Education, Division of Urology, Moscow, Russia. The whole procedures were recorded and key findings were reported in this video footage.
The first case was a 55 years old female who presented with stones up to 12 mm in the left kidney. Low pulse energy settings (0.1 J, 250 Hz) achieved effective stone dusting. Stone dusting was complete thirty minutes after first laser activation. Pop-corning was used for clearance of residual fragments. This could be achieved without any change of laser settings. Ten minutes of pop-corning were sufficient for complete stone disintegration. The second case was a 56 years old female who presented with a single stone of 15 mm in the left renal pelvis. It took a total of 24 minutes of operative time complete lithotripsy with breakdown products adhering to the snow globe effect, which is characteristic of stone dust. The third case was a 64 years old male who presented with a single stone of 30 mm in the left renal pelvis. It took 23 minutes for stone dusting and 14 minutes for pop-corning, resulting in a total operative time of 37 minutes for complete lithotripsy.
From this initial experience, we conclude that the SuperPulse Thulium fiber laser is applicable for lithotripsy of large renal stones in humans. At low pulse energy, it achieves effective stone dusting. Future studies are warranted to define optimal lithotripsy settings and further detail safety profile of the SuperPulse Thulium fiber laser.
Funding: Etienne Xavier Keller is supported by a Travel Grant from the University Hospital Zurich and from the Kurt and Senta Herrmann Foundation. Vincent De Coninck is supported by the EUSP scholarship from the European Association of Urology and by a grant from the Belgische Vereniging voor Urologie (BVU).