PD42-07 THE EFFECT OF CLEAVE TECHNIQUE AND LITHOTRIPSY DURATION ON LASER FIBER POWER OUTPUT

INTRODUCTION AND OBJECTIVES: Efficient laser lithotripsy is dependent on laser fiber tip power output. Burnback degradation is a well-documented cause of decreased power output, which may increase operative time. Reusable fibers are cleaved to remove the degraded tip and restore power output. The rate of power output loss during lithotripsy after cleaving with various techniques is not known. Such information is necessary to determine the optimal cleaving frequency and technique. The purpose of this study is to evaluate power output degradation with increasing lithotripsy duration following various cleave techniques. METHOD(S): In this randomized, prospective, single-blinded study 330 calcium oxalate monohydrate calculi were fragmented in a ureteral tube model submerged in normal saline using 200 and 365 mm diameter Lumenis reusable fibers. A Dornier Medilas H20 Ho: YAG pulsed laser was utilized at 8 Hz and 800 mJ (6.4 W). Fibers were cleaved using a ceramic scissor, a straight Mayo scissor, a scribe pen cleave tool, a diamond cleave wheel, and a #11 blade scalpel. Power output was measured at baseline and subsequently at 1 min intervals during stone ablation up to 15 min by an investigator blinded to the cleave technique. One hundred,15 min trials were performed including 10 per cleave technique on each fiber diameter. Independent-samples Mann-Whitney U, Kruskal-Wallis, and homogeneity of variances tests were used for statistical analysis with a significance of p