Initial clinical experience with the pulsed solid-state thulium YAG laser from Dornier during RIRS: first 25 cases.

ABSTRACT

INTRODUCTION: Holmiumyttrium-aluminium-garnet (HoYAG) and thulium fiber (TFL) lasers are currently the two laser sources recommended for endocorporeal laser lithotripsy (ELL). Recently, the pulsed-thuliumYAG (TmYAG) laser was also proposed for ELL, as an answer to both HoYAG and TFL limitations. We aimed to evaluate the efficiency, safety, and laser settings of TmYAG laser in ELL during retrograde intrarenal surgery (RIRS). METHODS: A prospective study of the first 25 patients with ureteral and renal stones who underwent RIRS using the Thulio (pulsed-TmYAG, Dornier©, Germany) was performed in a single center. 272 µm laser fibers were used. Stone size, stone density, laser-on time (LOT) and laser settings were recorded. We also assessed the ablation speed (mm3/s), Joules/mm3 and laser power (W) values for each procedure. Postoperative results, such as stone-free rate (SFR) and zero fragments rate (ZFR) were also recorded. RESULTS: A total of 25 patients were analyzed (Table 1). The median (IQR) age was 55 (44-72) years old. Median (IQR) stone volume was 2849 (916-9153)mm3. Median (IQR) stone density was 1000 (600-1174)HU. Median (IQR) pulse energy, pulse rate and total power were 0.6 (0.6-0,8)J, 15(15-20)Hz and 12(9-16)W, respectively. All procedures used "Captive Fragmenting" pulse modulation (Table 2). The median (IQR) J/mm3 was 14,8 (6-21). The median (IQR) ablation rate was 0,75 (0,46-2)mm3/s. One postoperative complications occurred (streinstrasse). SFR and ZFR were 95% and 55%, respectively. CONCLUSION: The pulsed-TmYAG laser is a safe and effective laser source for lithotripsy during RIRS, using low pulse energy and low pulse frequency.