Mattieu Haddad1,2,3, Esteban Emiliani1,2,4, Yann Rouchausse3, Frederic Coste3, Steeve Doizi1,2, Laurent Berthe3, Salvatore Butticé5, Bhaskar Somani2,6, Olivier Traxer1,2. 1. 1 Department of Urology, Tenon Hospital, Pierre and Marie Curie University, Paris VI , Paris, France . 2. 2 Groupe de Recherche Clinique sur la Lithiase Urinaire, GRC n°20, Sorbonne Universités, UPMC Univ, Paris VI, Department of Urology, Tenon Hospital , Paris XX, Paris, France . 3. 3 Process and Engineering in Mechanics and Materials Laboratory (PIMM), UMR CNRS/ENSAM , Paris VI, Paris, France . 4. 4 Department of Urology, Fundación Puigvert, Universidad Autónoma de Barcelona , Barcelona, Spain . 5. 5 Section of Urology, Department of Human Pathology, University of Messina , Messina, Italy . 6. 6 Department of Urology, University Hospitals Southampton NHS Trust , Southampton, United Kingdom .
Abstract
OBJECTIVE: To analyze the risk factors for laser fiber fractures when deflected to form a curve, including laser settings, size of the laser fiber, and the fiber bending diameter. MATERIALS AND METHODS: Single-use 272 and 365 μm fibers (Rocamed®, Monaco) were employed along with a holmium laser (Rocamed). Five different fiber curve diameters were tested: 9, 12, 15, 18, and 20 mm. Fragmentation and dusting settings were used at a theoretical power of 7.5 W. The laser was activated for 5 minutes and the principal judgment criterion was fiber fracture. Every test for each parameter, bending diameter, and fiber size combinations was repeated 10 times. RESULTS: With dusting settings, fibers broke more frequently at a curved diameter of 9 mm for both 272 and 365 μm fibers (p = 0.037 and 0.006, respectively). Using fragmentation settings, fibers broke more frequently at 12 mm for 272 μm and 15 mm for 365 μm (p = 0.007 and 0.033, respectively). Short pulse and high energy were significant risk factors for fiber fracture using the 365 μm fibers (p = 0.02), but not for the 272 μm fibers (p = 0.35). Frequency was not a risk factor for fiber rupture. Fiber diameters also seemed to be involved in the failure with a higher number of broken fibers for the 365 μm fibers, but this was not statistically significant when compared with the 272 μm fibers (p > 0.05). CONCLUSION: Small-core fibers are more resistant than large-core fibers as lower bending diameters (<9 mm) are required to break smaller fibers. In acute angles, the use of small-core fibers, at a low energy and long-pulse (dusting) setting, will reduce the risk of fiber rupture.
OBJECTIVE: To analyze the risk factors for laser fiber fractures when deflected to form a curve, including laser settings, size of the laser fiber, and the fiber bending diameter. MATERIALS AND METHODS: Single-use 272 and 365 μm fibers (Rocamed®, Monaco) were employed along with a holmium laser (Rocamed). Five different fiber curve diameters were tested: 9, 12, 15, 18, and 20 mm. Fragmentation and dusting settings were used at a theoretical power of 7.5 W. The laser was activated for 5 minutes and the principal judgment criterion was fiber fracture. Every test for each parameter, bending diameter, and fiber size combinations was repeated 10 times. RESULTS: With dusting settings, fibers broke more frequently at a curved diameter of 9 mm for both 272 and 365 μm fibers (p = 0.037 and 0.006, respectively). Using fragmentation settings, fibers broke more frequently at 12 mm for 272 μm and 15 mm for 365 μm (p = 0.007 and 0.033, respectively). Short pulse and high energy were significant risk factors for fiber fracture using the 365 μm fibers (p = 0.02), but not for the 272 μm fibers (p = 0.35). Frequency was not a risk factor for fiber rupture. Fiber diameters also seemed to be involved in the failure with a higher number of broken fibers for the 365 μm fibers, but this was not statistically significant when compared with the 272 μm fibers (p > 0.05). CONCLUSION: Small-core fibers are more resistant than large-core fibers as lower bending diameters (<9 mm) are required to break smaller fibers. In acute angles, the use of small-core fibers, at a low energy and long-pulse (dusting) setting, will reduce the risk of fiber rupture.
Entities:
Keywords:
deflection; fiber; laser; lower pole lithotripsy; uretersocopy; urolithiasis