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Comparing Mechanical Effects and Sound Production of KTP, Thulium, and CO2 Laser in Stapedotomy

Kamalski, Digna M. A.*†; Verdaasdonk, Rudolf M.; de Boorder, Tjeerd§; Vincent, Robert; Versnel, Huib*†; Grolman, Wilko*†

doi: 10.1097/MAO.0000000000000465

Hypothesis The mechanical and acoustic effects that occur during laser-assisted stapedotomy differ among KTP, CO2, and thulium lasers.

Background Making a fenestration in stapedotomy with a laser minimizes the risk of a floating footplate caused by mechanical forces. Theoretically, the lasers used in stapedotomy could inflict mechanical trauma because of absorption in the perilymph, causing vaporization bubbles. These bubbles can generate a shock wave, when imploding.

Methods In an inner ear model, we made a fenestration in a fresh human stapes with KTP, CO2, and thulium laser. During the fenestration, we performed high-speed imaging from different angles to capture mechanical effects. The sounds produced by the fenestration were recorded simultaneously with a hydrophone; these recordings were compared with acoustics produced by a conventional microburr fenestration.

Results KTP laser fenestration showed little mechanical effects, with minimal sound production. With CO2 laser, miniscule bubbles arose in the vestibule; imploding of these bubbles corresponded to the acoustics. Thulium laser fenestration showed large bubbles in the vestibule, with a larger sound production than the other two lasers. Each type of laser generated significantly less noise than the microburr. The microburr maximally reached 95 ± 7 dB(A), compared with 49 ± 8 dB(A) for KTP, 68 ± 4 dB(A) for CO2, and 83 ± 6 dB(A) for thulium.

Conclusion Mechanical and acoustic effects differ among lasers used for stapedotomy. Based on their relatively small effects, KTP and CO2 lasers are preferable to thulium laser.

Supplemental digital content is available in the text.

*Department of Otorhinolaryngology and Head & Neck Surgery, †Brain Center Rudolf Magnus, University Medical Center Utrecht; ‡Department of Physics and Medical Technology, VU University Medical Center Amsterdam; §Department of Medical Technology and Clinical Physics, University Medical Center Utrecht, The Netherlands; and ∥Jean Causse Ear Clinic, Transverse de Béziers, Colombiers, France

Address correspondence and reprint requests to Digna M. A. Kamalski, M.D., Department of Otorhinolaryngology, University Medical Center Utrecht: Heidelberglaan 100, G05.1293584 CX Utrecht, The Netherlands; E-mail:

Some of the laser equipment used for this study was provided by Omniguide, Cambridge, MA, USA.

The authors disclose no conflicts of interest.

Supplemental digital content is available in the text.

Copyright © 2014 by Otology & Neurotology, Inc. Image copyright © 2010 Wolters Kluwer Health/Anatomical Chart Company