Thulium Fiber Laser versus Vapor Tunnel HO:YAG laser in retrograde intrarenal surgery: which one has better laser ablation performance?

INTRODUCTION

Currently, Holmium:yttrium-aluminium-garnet (Ho:YAG) laser is the gold standard in the treatment of urolithiasis and Thulium Fiber Laser (TFL) has emerged as a new technology with several advantages in terms of dusting efficiency. With the technological advances and the knowledge of laser physics, various Ho: YAG pulse modalities have been emerged. To date, there are no studies that compare the laser ablation performance between TFL and Vapor Tunnel Ho:YAG laser (VT).

MATERIALS AND METHODS

A retrospective comparative study of 200 patients who underwent retrograde intrarenal surgery (RIRS) was performed. Patients were divided according to the laser that was used (TFL vs. VT). Stone volume and density, laser activity and total operative time were recorded. We assessed the laser energy consumption (Joules/mm), laser ablation efficiency (mm/Joules) and laser ablation efficacy (min/mm). The stone-free rate (SFR) was defined as the absence of stone fragments in a non-contrast abdominal computed tomography 4 weeks after the procedure.

RESULTS

100 patients were included in each group. Patients in TFL group presented significantly harder stones (915HU vs 801HU, p < 0.001) and significantly larger stones (797 mm vs 706 mm, p < 0.001). Total energy emitted (10.6 kJoules vs 14.8 kJoules), laser activity (14.7min vs 22.1 min) and total operative time (45.5 min vs 64 min) were significantly lower in TFL group. Laser ablation efficacy (20.5 vs 10.9 min/mm) and laser ablation efficiency (0.12 vs 0.041 mm/Joules) were significantly higher in TFL group. Finally, a significant lower energy consumption was obtained in this group (11.8 vs 17.1 Joules/mm). SFR was comparable between both groups (81% vs 82%, p = 0.85).

CONCLUSION

TFL was associated with less laser time and total operative time. Furthermore, it increased lithotripsy efficacy and efficiency while decreasing the laser energy consumption compared with VT Ho:YAG laser.