Abstract
Laser surgery in general is becoming more and more common, and there are now several types of lasers used for middle ear surgery. However, surgeons can only depend on their own clinical experience when selecting which type of laser to use because there is almost no basic research to which they can refer. We have therefore analyzed the light absorption spectra for temporal bone and the ossicles of the middle ear in order to find which type of laser is best for treating these tissues. We found that the auditory ossicles had three light absorption peaks: first at 3.03 μm, second at 6.10 μm and third at 9.83 μm. We therefore selected the CO2 laser (λ : 10.6 μm) and Er:YAG laser (λ : 2.94 μm) to irradiate the incus. The hole made by the CO2 laser was relatively shallow with rounded edges, and there was carbonization on the surrounding surfaces. Also, the irradiated surface was rough and covered with many micro-cracks. On the other hand, the hole made by the Er:YAG laser was deeper and free of carbonization, and the irradiated surface was smooth without irregularities or micro-cracks. These results strongly suggest that the Er:YAG laser is better suited for treatment of the auditory ossicles.
