Erbium: YAG laser lithotripsy using hybrid germanium/silica optical fibers

Yubing Yang, Charles A. Chaney, Nathaniel M. Fried

Research output: Contribution to journalArticlepeer-review

Abstract

Background and Purpose: Previous studies have demonstrated that the erbium:YAG laser is two to three times more efficient for laser lithotripsy than the holmium:YAG laser. However, the lack of a suitable optical fiber delivery system remains a major obstacle to clinical application of Er:YAG laser lithotripsy. This paper describes the initial testing of a hybrid germanium oxide/silica optical fiber for potential endoscopic use with the Er:YAG laser. Materials and Methods: Er:YAG laser radiation with a wavelength of 2.94 μm, a pulse energy of 10 to 600 mJ, a pulse length of 220 μsec, and pulse-repetition rates of 3 to 10 Hz was focused into either 350- or 425-μm-core hybrid germanium/silica fibers in contact with human uric acid or calcium oxalate monohydrate stones. Results: Average Er:YAG pulse energies of 157 ± 46 mJ (66 J/cm2) (N = 8) were delivered at 10 Hz through the 425-μm hybrid fibers in contact with urinary stones before fiber damage was observed. A maximum pulse energy of 233 mJ (98 J/cm2) was also measured through the hybrid fiber in contact with the stones. These values are significantly greater than the stone ablation thresholds of 15 to 23 mJ (6-10 J/cm2) and the fiber damage thresholds measured for germanium oxide, 18 ± 1 mJ (13 J/cm2), and sapphire, 73 mJ (51 J/cm 2), optical fibers during Er:YAG laser lithotripsy (P <0.05). Conclusions: A prototype hybrid germanium/silica optical fiber demonstrated better performance than both germanium oxide and sapphire fibers for transmission of Er:YAG laser radiation during in vitro lithotripsy.

Original languageEnglish (US)
Pages (from-to)830-835
Number of pages6
JournalJournal of Endourology
Volume18
Issue number9
StatePublished - Nov 2004

ASJC Scopus subject areas

  • Urology

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