Masahiro Kawaida

Lubrication Mechanism of the Larynx during Phonation: An Experiment in Excised Canine Larynges

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 vibration of the free edge and the peak glottal area was decreased while the open quotient was increased. Because the viscosity of this fluid affected the wave motion of the vocal fold mucosa, changes in viscosity of the mucus may be involved in causing such disorders as hoarseness, in the absence of apparent changes in the vocal folds themselves.

Voice prognosis after liquid and solid silicone injection

A study was undertaken to determine the voice prognosis in 51 of the 408 patients with unilateral recurrent laryngeal nerve paralysis who had visited the Department of Ear, Nose and Throat at Keio University between 1977 and 1984. The 51 patients were divided into three groups: 18 patients without silicone injection, 15 with a silicone liquid implant, and 18 with a silicone solid implant. Data are provided to show that (1) both types of silicone implant are tolerated by the body and effective in improving voice and that (2) the liquid implant is ultimately absorbed and therefore useful for temporary voice improvement in patients in whom the prognosis for vocal fold paralysis is not known, whereas the solid implant is not absorbed and is therefore effective in the long term when recovery can be ruled out.

Video-Assisted Rigid Endoscopic Laryngosurgery: Application to Cases with Difficult Laryngeal Exposure

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 the video monitor. We describe the surgical procedure together with the preoperative and postoperative evaluation of vocal function in 13 patients with benign laryngeal lesions. A good surgical and vocal outcome was achieved in all cases. The method appeared to be useful for treating dysphonia in patients in whom it was difficult to expose the larynx with a direct laryngoscope.

Digital image processing of laryngeal lesions by electronic videoendoscopy

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.

Clinical Experience With a New Type of Rhino-Larynx Electronic Endoscope PENTAX VNL-1530

We observed recordings of pictures obtained from patients with diseases of the larynx by using a new type of rhino-larynx electronic endoscope, PENTAXVNL-1530 connected to a video processor, PENTAX EPM-3300 (Asahi Optical Co., Ltd.). The electronic endoscope differs from the fiberoptic endoscope in that it contains a small light-sensitive charge coupled device (CCD) chip that is attached to the tip of the endoscope. This electronic endoscope has the smallest CCD camera of 5.1 mm in diameter, in the tip portion, and can be passed through the nasal passage into the laryngeal cavity. The dynamic image provided by this system is superior to that obtained by a flexible laryngofiberscope in resolution of the detail. The system with this electronic endoscope was introduced and some clinical cases were presented.

Displacement of the Ventricular Fold Following Cordectomy

In order to avoid radiation and its undesirable side effects, we have employed surgical techniques for treatment of early glottic cancer when the lesion is confined to one membranous cord (Fukuda, Saito, Sato, and Kitahara: J. Jpn. Bronchoesophagol. Soc. 30: 7-14, 1979; Fukuda and Saito: Otologica 26: 434-436, 1980; Fukuda, Kawaida, Ohki, Kawasaki, Kita, and Tatehara: J. Jpn. Bronchoesophagaol. Soc. 39: 139-144, 1988). Laser is one of the most popular techniques and it has been accepted as the first choice by many authors (Annyas, Overbeek, Escajadillo, and Hoeksema: Laryngoscope 94: 836-838, 1984; Mcguirt and Koufman: Arch. Otolaryngol. Head Neck Surg. 113: 501-505, 1987; Tsuji, Fukuda, Kawaskai, Kawaida, and Kanzaki: Keio J. Med. 38: 413-418, 1989). However, some cases are difficult to approach by direct laryngoscopy, requiring an external way to expose the lesion. In these cases, cordectomy by laryngofissure is the method of choice, but the function of the glottis could be improved by replacing the excised cord displacing the ventricular fold. This technique, designed by the authors, was carried out in 22 patients and the results from the viewpoint of phonodynamics, voice quality, and cure rate are discussed in this study. The results are encouraging and we believe that this method is a very reasonable alternative to the laser when such equipment is not available. We also believe that late side effects and oncogenic problems associated with radiation are important points to be considered, especially in patients of relatively younger age.

Observations of Laryngeal Lesions with a Rhinolarynx Electronic Videoendoscope System and Digital Image Processing

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 tip of the endoscope portion. This model has a small CCD chip in its 5-mm-outer diameter tip, and can be introduced into the laryngeal cavity by inserting it through the nasal passages. Dynamic color images obtained by this system were very clear and provided excellent resolution. This electronic videoendoscope system could also be connected to the Olympus EVIP-230 digital image processor, which was compatible with this system. Structure enhancement and color enhancement were performed by processing images. In this paper, the ordinary images and the processed images are described and discussed from the standpoint of diagnostic usefulness.

Surgical Treatment of Large Epiglottic Cysts with a Side-Opened Direct Laryngoscope and Snare

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. The removal of the cysts was accomplished by using this direct laryngoscope and a snare under inhalation anesthesia by fiber optic guided endotracheal intubation. The side-opened direct laryngoscope enabled easy insertion of the snare through the right side opening.

Isolated Non-Hodgkin’s Malignant Lymphoma of the Larynx Presenting as a Large Pedunculated Tumor

This paper presents a case of non-Hodgkins lymphoma (NHL) of the larynx. The patient was an 86-year-old man who complained of foreign-body sensation and dysphagia. Laryngoendoscopic examination revealed a large pedunculated mass arising from the left aryepiglottic fold. A diffuse, large, B-cell-type NHL was diagnosed histopathologically. The patient was treated with combination chemotherapy, resulting in complete clinical remission. The clinicopathological features of this case have been described and compared with previously reported cases.

Primary Small Cell Carcinoma of the Larynx

Small cell carcinoma is a rare tumor of the larynx. We present such a case in a 78-year-old female. The histopathological diagnosis at the time of laryngomicroscopic biopsy was squamous cell carcinoma, upon which basis we initially chose surgical treatment. The surgical specimen, however, revealed small cell carcinoma. Despite the administration of radiotherapy and chemotherapy, the patient died 9 months after initial presentation. We believe that this case illustrates the need for a sufficiently large biopsy specimen in order to arrive at the correct histopathological diagnosis when small cell carcinoma of the larynx is present, and that immunohistochemistry and electron microscopy should be performed to aid the diagnosis.