Holmium:Yttrium-aluminum-garnet lithotripsy proximal fiber failures from laser and fiber mismatch

OBJECTIVES To document proximal fiber failures at the subminiature version A connector during holmium. yttrium-aluminum-garnet lithotripsy when fibers and lasers are mismatched. METHODS Optical fibers supplied by Trimedyne were coupled to holmium:yttrium-aluminum-garnet lasers from Lumenis (VersaPulse 100 W), New Star (NS1500 12 W), and Dornier (Medilas H20) for an in vitro experiment. We reviewed the operating room laser log for our Lumenis VersaPulse 100 W laser for an in vivo experiment. The lasers were maintained with the rods aligned. The use of a different brand, small caliber (diameter less than 300 mu m) and larger fibers and the number of proximal fiber failures were recorded. RESULTS The in vitro experiment was stopped prematurely because the fiber failed on the New Star laser with an audible explosion sound and smoke emanating from the connector end. The fiber could not be extracted from the laser. The fiber at its connector end had melted and fused to the laser terminal. In vivo, 4% of all cases using the sub-300-mu m fibers had connector end failures versus 0% of 365-mu m fibers, and 0% of 550-mu m fibers (P <0.001). Of 188 consecutive cases using the sub-300-mu m fibers, 4 (13%) of 30 cases had connector end failures using the Trimedyne fiber versus 3 (2%) of 155 cases using the Lumenis fiber (P <0.01). CONCLUSIONS The mismatch of small-caliber fibers with lasers runs the risk of fiber failure, energy reflected back at the laser, and laser damage. Urologists should familiarize themselves with the specifications of their holmium:yttrium-aluminum-garnet lasers and fibers to avoid expensive laser repairs.