Biomedical subjects

M Ishidoya

Publications and source records attributed to M Ishidoya.

4 recordsLinked to original sources

PubMed1995

Treatment of labyrinthine fistula with interruption of the semicircular canals.

Evaluation of postoperative hearing acuity and equilibrium was performed in eight patients with labyrinthine fistula caused by cholesteatoma, in which at least one of the semicircular canals (five cases, lateral; one case, superior; one case, posterior; and one case, both lateral and superior) was interrupted during eradication of the matrix and granulations from the semicircular canals. The interrupted semicircular canals were obliterated firmly with autologous materials such as fascia, perichondrium, bone chips, and cartilage. The observation period ranged from 9 months to 3.3 years. Postoperative hearing was unaltered or improved in seven patients, and decreased by 12 dB in one patient. Postoperative disequilibrium lasting more than 2 weeks was experienced in two patients and disappeared at the second and fifth postoperative months, respectively. Relief from fistula symptoms was complete after surgery, indicating adequacy of this procedure in one-stage open-method tympanoplasty. The present study indicates that manipulation of the semicircular canal with awareness can be conducted without damaging the cochlear function, and that the treatment of labyrinthine fistulas should be performed very carefully but not so conservatively as to lead to future problems. In some cases of deep fistulas of the semicircular canals, interruption and/or obliteration of the semicircular canals can be the most proper procedure.

Adult↗

PubMed1994

Pathogenesis of attic retraction pocket and cholesteatoma as studied by computed tomography.

It is hypothesized that blockade of the tympanic isthmus causes isolation of the attic and the adjacent middle ear spaces and that subsequent building up of the negative pressure in these spaces results in retraction of the pars flaccida, leading to formation of attic retraction pockets and cholesteatomas. To examine this theory, computerized tomographic (CT) findings of these conditions were evaluated in a series of 53 ears with retractions of the pars flaccida (attic retractions of Tos type II or deeper), including both retraction pockets and cholesteatomas. In 26 of 28 ears with attic retraction pockets, at least a portion of attic was aerated, and in 22 of these 26 ears, the mastoid antrum was also aerated. In contrast, in the 25 cases with attic cholesteatomas, these numbers decreased to 10 and 5, respectively, and the lack of aeration of the attic was demonstrated in 15 of 25 (60%) of the cases. In three cases of cholesteatoma, follow-up CT revealed either growth of a cholesteatoma from a retraction pocket or development of a small cholesteatoma into a large one. In these ears it was seen that the well-pneumatized attic and mastoid antrum seen in the initial CT was depleted by the growth of cholesteatoma that took place over a period of 4 months to 2 years. These results, showing good patency of the aditus and a pneumatized antrum in early stages of most cases of retraction pockets and cholesteatomas, are not in agreement with the hypothesis that the blockade of the tympanic isthmus is responsible for the pathogenesis of retraction pockets and cholesteatomas originating in the pars flaccida.

Adolescent↗

PubMed1990

Changes in tympanograms after middle ear inflation.

To determine the effects of politzerization or middle ear (ME) inflation by a catheter, we studied the ME pressures in 35 ears with retracted tympanic membranes (29 patients). Serial tympanometries were performed prior to the ME inflation and immediately, 10, 20, 30 and 60 min after the procedure. The present study showed that the more negative the ME pressure was before the inflation, the greater the pressure change was after the treatment. The elevated ME pressure induced by the procedure declined rapidly within the first 20 min after the inflation. This was probably caused mainly by spontaneous elimination of ME gas through the eustachian tube and gas absorption from the ME mucosa. During the post-inflation course, some ears demonstrated more negative pressures in the ME cavity than those before the inflation. The present investigation demonstrated that the use of inflation to treat secretory otitis media had short-term benefits which could be improved by minimizing gas absorption.

Acoustic Impedance Tests↗

PubMed1988

A case of carcinoid tumor of the middle ear producing peptide hormones.

We report 6th case of carcinoid tumor of the middle ear in a 16-year-old man. The clinical, histologic, immunohistochemical and ultrastructural features are discussed. The tumor in the attic and the tympanic cavity was successfully excised by radical mastoidectomy. Microscopically, the argyrophilic property and neurosecretory granules which are characteristic of carcinoid tumor were found in the cytoplasm of tumor cells. Furthermore, peptide hormones were confirmed immunohistochemically in this case. This tumor should be considered in the differential diagnosis when biologically lowgrade tumor with glandular and trabecular architectures are encountered in the middle ear.

Adolescent↗