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Thermic effects in the “vestibule” during laser stapedotomy with pulsed laser systems
Author(s) -
Jovanovic S.,
Schönfeld U.,
Fischer R.,
Döring M.,
Prapavat V.,
Müller G.,
Scherer H.
Publication year - 1998
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/(sici)1096-9101(1998)23:1<7::aid-lsm2>3.0.co;2-t
Subject(s) - vestibule , laser , medicine , anatomy , materials science , optics , physics , audiology , vestibular system
Background and Objective Apart from the ablation properties at the stapes footplate, the degree of thermic loading in the inner ear is important in determining the suitability of pulsed lasers for stapedotomy. The aim of the study is to compare the thermic effects in the vestibule with different pulsed laser systems. Study Design/Materials and Methods: Temperature increases and heat exchange processes in the fluid (physiological saline) were examined in a calorically and physiologically approximated cochlea model for applying the laser parameters effective in creating footplate perforations. Results With all systems, increases in the energy density, number of pulses, and thus resultant total energy lead to higher temperatures. In the effective energy density range, the highest temperature increases achieved with the requisite number of pulses at a distance of 2 mm behind the perforation are 26°C with the Ho:YAG laser. The lowest temperature maxima are 5.5°C with the Er:YAG and <5°C with the Er:YSGG laser. The excimer laser, investigated at only one energy density, showed maximal temperatures of 10°C. Conclusion The Er:YSGG and Er:YAG laser can be applied in laser stapedotomy in a relatively broad energy density range without a risk of inner ear damage by thermic loading. On the other hand, the Ho:YAG laser is not recommended for stapedotomy because of the higher energy density and pulse rate required for sufficient perforation and the resultant higher temperature increases in the perilymph. Though likewise achieving perforations with only slight temperature increases in the fluid of the cochlea model, the excimer laser does not seem appropriate for stapedotomy because of the long period of heat exposure (ca. 60 s) due to the lower ablation rate at the stapes necessitating a longer application time. Lasers Surg. Med. 23:7–17, 1998. © 1998 Wiley‐Liss, Inc.