PD30-01 COMPARISON OF SMALL CORE DIAMETER LASER FIBERS USED FOR LITHOTRIPSY WITH A 120W HO

Abstract

INTRODUCTION AND OBJECTIVE: Small core (240 - 300μm) fibers are used for Ho:YAG laser lithotripsy. The SOLTIVE SuperPulsed Thulium Fiber (SPTF) Laser permits the use ≤ 200μm core sized fibers. We evaluate a 150μm and 200μm core size fiber used with the SPTF laser compared to a 242μm and 230μm core fiber used for Ho:YAG laser lithotripsy. METHODS: Fiber flexibility, mechanical breakdown and thermal breakdown are tested with the BSC Accumax 200 (242μm core), Lumenis SlimLine MOSES™ (230μm core), Olympus 200 SPTF (200μm core) and Olympus 150 SPTF (150μm core). Fiber flexibility is shown via a 3-point bend test 5x for each fiber size (results in N/mm). A 2-plate break test measures the tightest diameter a fiber could be bent before failure (N=5). For thermal breakdown, fibers were bent 180° at a diameter of 3cm during firing at pulse energies of 0.2, 0.5, 1, and 2 J, all at 10 Hz, in successive order for 15s or until fiber failure. If no failure, the bend diameter (BD) was reduced and the testing repeated until failure or 0.2 cm reached. BD = 3, 2, 1, 0.5, 0.4, 0.3, and 0.2cm were sequentially tested. Five trials for each fiber were performed. RESULTS: The 150 SPTF was less stiff than the 200 SPTF (Mean 0.0055 vs 0.0076 N/mm). Both fibers were less stiff than the Accumax 200 and MOSES 200 (Mean 0.014 & 0.0098 N/mm). Mean BD before mechanical failure was 0.099 mm for the 150 SPTF, 1.58 mm for the MOSES 200, 1.74 mm for the Accumax 200 and 1.861mm for the 200 SPTF. For thermal breakdown testing, the 150 SPTF reached BD = 0.3 cm prior to failing in 3/5 trials, with a BD = 0.2cm in 2/5, at pulse energy of 0.2 J. The 200 SPTF BD = 0.4 cm prior to failing in 2/5 trials, with a BD = 0.3cm in 3/5 trials, at a pulse energy of 0.2 J. The Accumax 200 failed at BD = 0.4 – 1.0 cm and pulse energies of 0.2 – 1.0J. For the MOSES™ 200, BD = 0.5cm in all trials, failing at pulse energies of 0.2-2.0J (Figure 1). CONCLUSIONS: The 150 and 200 SPTF fibers were more flexible and able to bend to a smaller diameter than the Accumax 200 and MOSES™ 200 fibers with laser energy pulsing through them. These fibers may provide clinical benefits during laser lithotripsy procedures, especially in the difficult to reach lower pole.Source of Funding: Olympus Surgical