Masahiro Kawaida

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Laryngeal lesions were observed with the Olympus ENF-200 rhinolarynx electronic videoendoscope attached to the Olympus EVIS-200 system, an electronic videoendoscope system of Olympus Optical Co, Ltd. The electronic videoendoscope differs from conventional flexible fiberscopes in having a small light-sensitive charge-coupled device (CCD) chip built into the(More)
In order to establish precise vibratory patterns and their clinical implication for phonation, the mode of vibration of the vocal folds around the time of register transition in excised canine larynges was analyzed multi-directionally according to various acoustic parameters. Phonation was simulated by artificially tensing the cricothyroid muscles.(More)
To evaluate how the viscosity of the laryngeal mucus influences vocal fold vibration, two fluids of differing viscosity were applied separately to excised canine larynges and experimental phonation was induced. Vibration of the vocal folds was measured by use of a laryngostroboscope and an X-ray stroboscope. With the high viscosity fluid, the amplitude of(More)
In some cases of microlaryngosurgery, laryngeal exposure with a direct laryngoscope is difficult because of a variety of reasons. In such cases, we now use a long rigid endoscope inserted into the side tube of the direct laryngoscope together with a video system. The lesion can be removed while the phonosurgeon observes the magnified images of the larynx on(More)
OBJECTIVES To present electronic videoendoscopy of the larynx with digital image processing and to discuss this endoscopic technique from the standpoint of diagnostic usefulness of laryngeal lesions. STUDY DESIGN Electronic videoendoscopic evaluation of laryngeal lesions with digital image processing. METHODS Seventy patients underwent electronic(More)
Actinomycosis is a disease characterized by a chronic suppurative and granulomatous process which tends to form multiple pyogenic draining sinus tracts. The most common site in which it occurs is the cervico-facial region, especially in the submandibular area. The exudates from the fistulous tracts usually contain yellow granules known as "sulfur granules,"(More)
Two cases of large epiglottic cysts are reported. Histopathological examination revealed a retention cyst in one case and an epidermoid cyst in the other. We designed a side-opened direct larngoscope and snare for treating epiglottic cysts. This direct laryngoscope is characterized by an opening from the anterior tip to the posterior end of the right side.(More)
Two cases of hypopharyngeal cyst are reported. Both cysts occurred in the piriform sinus of the hypopharynx. Histopathological examination indicated that both were retention cysts. These cysts were removed by laryngomicrosurgical technique using a side-opened direct laryngoscope. In the cyst with a distinct base, a laryngomicrosurgical snare was used for(More)
Microscopic direct laryngoscopy (microlaryngoscopy) under general anaesthesia is the optimal method of observing the larynx. However, as microlaryngoscopy does not allow precise observations of the ventricle, inferior surface of the vocal fold and subglottis, multidirectional observations of the larynx using transurethral rigid endoscopes were performed(More)
When endolaryngeal microscopic laryngosurgery (microlaryngosurgery) with a direct laryngoscope is used to remove lesions of the posterior glottal area under endotracheal general anesthesia, the endotracheal tube interferes with the surgical field. To overcome this problem, we developed a special direct laryngoscope with a concave groove on the upper portion(More)