Shigejiro Kurita

Ageing of the Vibratory Tissue of Human Vocal Folds

Sixty-four human larynges ranging in age between 70 and 104 years were investigated histologically. The results were incorporated into our previous data for younger age groups. Discussion was focused on the mucosa around the vocal fold edge. The following tendencies were observed with ageing: (1) the membranous vocal fold shortens in males; (2) the mucosa thickens in females; (3) the cover of the vocal fold thickens in females; (4) edema develops in the superficial layer of the lamina propria in both sexes; (5) the intermediate layer of the lamina propria thins and its contour becomes deteriorated in males; (6) elastic fibers in the intermediate layer become less dense and atrophy in males; (7) the deep layer of the lamina propria thickens in males; (8) collagenous fibers in the deep layer become denser and fibrotic in males. The degree of these geriatric changes vary from individual to individual.

Posterior Glottis Morphological Study in Excised Human Larynges

Two sets of investigations were conducted with excised human larynges. 1) The glottis was closely observed and photographed from above and below in three conditions: neutral, adduction, and abduction. 2) The structure surrounding the posterior glottis was histologically investigated in the same three conditions. The results are as follows. 1) The structure surrounding the posterior glottis consists of three portions: the posterior wall of the glottis, the lateral wall of the posterior glottis, and the cartilaginous portion of the vocal fold. 2) During vocal fold adduction, the posterior part of the larynx closes completely not at the glottis but at the supraglottis, resulting in formation of a conic space in the posterior glottis that can be viewed only from below. 3) The posterior glottis accounts for approximately 35% to 45% of the entire glottic length and 50% to 65% of the entire glottic area. 4) The mucosa of the posterior glottis has ciliated epithelium. The lamina propria consists of two layers. 5) The posterior glottis can be regarded as a respiratory glottis.

Asymmetry of the Laryngeal Framework: A Morphologic Study of Cadaver Larynges

Asymmetry of the laryngeal framework was investigated with 50 excised human larynges, ten from newborns (five males, five females), 20 from adults in their 20s (ten males, ten females), and 20 from adults in their 50s (ten males, ten females). All adults were right-handed. The results are summarized as follows. 1) The laryngeal framework was asymmetric to a greater or lesser extent in all larynges. 2) The degree of asymmetry did not differ among different age groups or between sexes. 3) In newborns, there was no directional preponderance in asymmetry. 4) In older adults, there was a directional preponderance in asymmetry. The right thyroid lamina tended to tilt laterally whereas the left lamina showed a tendency to tilt medially. The right cricoarytenoid joint tended to be located slightly more laterally, posteriorly, and inferiorly than the left joint. The longitudinal axis of the thyroid cartilage was inclined to shift to the right posteriorly against the axis of the cricoid cartilage. The thyroid cartilage as a whole tended to tilt to the right against the cricoid cartilage. 5) There must be some compensatory mechanisms for the asymmetric framework to keep the vocal fold edges relatively symmetric.

Deglutition following Supraglottic Horizontal Laryngectomy

In order to determine factors that may contribute to deglutition problems following supraglottic horizontal laryngectomy or its modified techniques, clinical records of 38 patients were studied. Contribution of the following factors was investigated: Age; sex; tumor classification; radical neck dissection; extent of and symmetry in removal of the aryepiglottic folds, arytenoid cartilages, and false folds; removal of the base of the tongue, hyoid bone, and a part of the vocal folds; extent of removal of the epiglottis and thyroid cartilage; cricopharyngeal myotomy; and some complications and concomitant diseases. The results suggest that removal of the arytenoid cartilage and asymmetrical removal of the false folds contribute to deglutition problems. We conclude that the standard supraglottic horizontal laryngectomy associated with surgical approximation of the larynx to the base of the tongue and cricopharyngeal myotomy does not usually cause serious deglutition problems. When the arytenoid cartilage is removed, reconstruction of the structure is required for the prevention of severe aspiration.

Vocal Fold Polyps and Nodules. A 10-Year Review of 1,156 Patients

We investigated the clinical records of 784 patients with vocal fold polyps and 372 patients with vocal fold nodules who were seen in our clinic during the 10 years from 1971 to 1980. Polyps were frequent in middle ages in both sexes whereas nodules were common in boys and middle-aged women. Vocal abuse was the most important etiologic factor. No regular voice therapy was available for lack of voice therapists. Surgical removal yielded the best result, but not in all the patients operated.

Vocal function following hemilaryngectomy

Vocal function following hemilaryngectomy was investigated in 54 cases in which a superiorly based sternohyoid muscle flap was used for glottic reconstruction. Four types of material were employed for covering the muscle flap: Hypopharyngeal mucosa, lip mucosa, thyroid perichondrium, and island cervical skin flap. The vocal function varied greatly from individual to individual; however, the following tendencies were observed in many cases: 1) the glottis did not close completely; 2) supraglottic structures (false fold, arytenoid region, and epiglottis) were hyperfunctional and vibrated instead of or together with the unaffected vocal fold; 3) vibrations of the laryngeal structures were irregular; 4) maximum phonation time was short; 5) mean airflow rate was high; 6) fundamental frequency and intensity ranges of phonation were limited; 7) the voice was rough, breathy, and/or strained; and 8) cases with poor vocal function were most frequent in the skin flap group and least frequent in the lip mucosa group.

Structure and Mechanical Properties of the Vocal Fold

Publisher Summary This chapter discusses the structure and mechanical properties of the vocal fold. Three independent parameters, E a , E i , and G a , specify an orthotopic medium, provided that the medium is incompressible. The modulus measured under the longitudinal tension corresponds to E a , whereas that measured under the transverse tension corresponds to E i . The shear modulus measured with a rotation around the longitudinal axis corresponds to G a . The values of E a and E i are the differential Youngs moduli taken from the same region of elongation in which G a s are also measured. The chapter also discussed the directionality of the tissue properties based on the histological findings and ones experimental result. The tissue components of the lamina propria that significantly affect the mechanical properties of the tissue are (1) collagenous fibers tightly connected longitudinally but loosely connected transversally, (2) elastic fibers running in every direction like a network, and (3) the ground substance having a gelatinous property

Location of the preepiglottic space and its relationship to the paraglottic space.

An investigation was carried out to determine the location of the preepiglottic space (PES) and its relationship to the paraglottic space (PGS). Excised human adult larynges served as materials for this study. The distribution of the PES of the larynx was determined histologically in 3 whole organ serial sections: sagittal, horizontal, and coronal. The results are summarized as follows. 1) The PES exists not only anterior, but also posterolateral and inferolateral to the epiglottis. 2) Its posterior end is located in the vicinity of the anteroposterior midpoint of the thyroid lamina. 3) The PES is adjacent to the PGS posteroinferiorly and is separated by fibrous tissue (the thyroglottic ligament). Posterosuperiorly, the 2 spaces are not clearly delineated from each other.

Vocal Fold Fixation in Laryngeal Carcinomas

The mechanisms of vocal fold fixation were determined by means of a whole-organ serial section study. A total of 80 laryngectomy specimens, 36 supraglottic and 44 glottic carcinomas, was investigated. In the supraglottic carcinomas, the most frequent cause of fixation of the ipsilateral vocal fold was a deep massive tumor invasion in the arytenoid eminence and the second most frequent cause was an extensive involvement of the thyroarytenoid (TA) muscle. Fixation of the contralateral vocal fold resulted from a deep tumor invasion in the contralateral arytenoid eminence. In the glottic carcinomas, fixation of the ipsilateral vocal fold resulted from an extensive invasion into the TA muscle. Fixation of the contralateral vocal fold was caused chiefly by an invasion into the contralateral TA muscle through the anterior commissure region. It resulted occasionally from an invasion into the interarytenoid muscle and contralateral arytenoid cartilage and cricoarytenoid joint via the posterior part of the larynx.

Distribution of Elastic Cartilage in the Arytenoids and its Physiologic Significance

An investigation of the distribution of the elastic cartilage in the arytenoids was performed on excised human adult and newborn larynges. The distribution of elastic cartilage in the arytenoids was investigated histologically in two serial sections: Horizontal and coronal. The behavior of the elastic cartilage portion of the arytenoids was investigated histologically under the conditions of adduction and abduction. The results are summarized as follows. 1) Elastic cartilage is found not only at the tip of the vocal process but at the superior portion of the arytenoid cartilage from the vocal process to the apex. 2) This phenomenon is observed at birth. 3) The vocal process bends at the elastic cartilage portion during adduction and abduction. The sides of the arytenoids come into contact mainly at the elastic cartilage portion. 4) Elastic cartilage appears to play an important role in the physiologic functioning of the arytenoid.