Laser lithotripsy (LL) has become a first-line modality for the intracorporeal treatment of urinary tract stones. The current gold standard laser source for LL systems is a Ho:YAG (Ho) laser emitting at the wavelength of 2.10 µm. Recently, a SuperPulse Tm fiber laser emitting at 1.94 µm has been proposed as a viable alternative to Ho laser. We report our initial experience with clinical application of the new SuperPulse Thulium (Tm) fiber laser system and its comparison with modern high power Ho system.
SuperPulse Tm fiber laser has been recently cleared for clinical application by the Ministry of Health of Russian Federation. The study protocol has been approved by the institutional Ethical Review board. A top-of-the-line Ho system (up to 120 W average power, 80 Hz rep rate) was compared with the SuperPulse Tm fiber laser system (up to 50 W average power, 2000 Hz rep rate). The study is still on-going. Up to October 2017, total of 56 patients with 68 stones (age range 19-82) have been enrolled into the study. Each stone has been surgically treated with at least one device. For stones > 1 cm in size (16 cases) half of the stone was treated with Ho laser and the other half with Tm laser; for smaller stones, matched pairs of stones were selected for comparison. Total procedure time, “laser on” time, stone extraction (when applicable) time, as well as stone retropulsion level were assessed.
On the dataset obtained and analyzed so far, the total procedure time varied between 17 and 25 min, with no significant difference between the lasers. The “laser on” time was shorter for Tm system, by a factor of 1.5 in fragmentation mode, and by a factor of 3 in dusting mode. Stone retropulsion level was greatly reduced for Tm laser. No cases of accidental damage of soft tissues were reported with either system. The average post-operative hospital stay time was 2.4 days, regardless of the laser used.
Data available so far indicate that SuperPulse Thulium fiber laser is at least as efficacious and safe as top-of-the-line Ho:YAG laser, while offering significantly shorter (in terms of “laser on” time) treatment time and reduced retropulsion, thus increasing the comfort level and decreasing fatigue of the operating surgeon.