Thulium vs. Hol:YAG Laser

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.

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.