Thulium vs. Hol:YAG Laser

Superpulsed Thulium Fiber Laser VS. Pulse Modulated High Power Holmium:YAG Laser For Retrograde Intrarenal Surgery

This is a randomized prospective study to compare stone free rates and operative efficiency of two laser systems used during retrograde intrarenal surgery for kidney stone disease: A superpulsed thulium fiber laser (thulium) A pulse modulated high power holmium laser (Holmium)

This is a randomized prospective study. The purpose is to compare the stone free rate and operative efficiency of two leading contemporary laser systems used during retrograde intrarenal surgery for kidney stone disease. The researchers will compare the following two systems: A superpulsed thulium fiber laser (thulium) A pulse modulated high power holmium laser (Holmium) The researchers will recruit 82 subjects undergoing single stage unilateral ureteroscopy for renal stones with a volume between >5mm to < 20 mm. Subjects will be randomized to undergo lithotripsy with either Ho:YAG or Thulium lasers. All subjects will undergo surgical interventions that abide by broadly accepted guidelines and standards of care. The primary outcome is stone free rate evaluated by postoperative CT scans done 6-12 weeks after surgery.

Patients who are randomized to undergo ureteroscopic laser lithotripsy with the Thulium fibre laser (TFL)

Patients who are randomized to undergo ureteroscopic laser lithotripsy with the Holmium:Yttrium-Aluminum-Garnet (Ho:YAG) laser

The TFL is a relatively new laser in the field of urology. First introduced on the market in 2017, it offers theoretically superior stone dusting qualities and smaller fiber sizes to allow for better irrigation.

The Ho:YAG is currently the most commonly used laser in the field of urology and for the better part of the last 3 decades has been considered the gold standard for laser lithotripsy.

Fragmentation speed is calculated by dividing stone volume by lasing time (mm3/sec). This is a measure of how quickly the laser breaks down the kidney stones.

Lasing activity is calculated by dividing lasing time by lithotripsy operative time (%). This measures the percentage of time during surgery that the surgeon is actively using the laser to break down kidney stones.

Energy utilization is calculated by dividing laser energy by stone volume (J/mm3). This is a measure of how much laser energy is needed to break down a stone.

Inclusion criteria: Undergoing single stage unilateral RIRS for total stone burden volume >5mm to < 20 mm Preoperative CT scan for baseline measurements Exclusion criteria: Anatomic variations: horseshoe kidney, pelvic kidney, ptotic kidney, urinary diversion or ureteral stricture Ureteral stent Uric acid component >50% on stone analysis Prior ureteroscopy within 6 weeks of current surgery Irreversible coagulopathy Urothelial tumor(s), direct extraction of the stone(s) without needing laser lithotripsy, and failure to reach the stone in the upper urinary tract with the ureteroscope.

No individual participant data will be shared. Aggregate results will be published by the investigators in academic journals.