1998 Fiscal Year Final Research Report Summary
Pathogenesis and new treatments of middle ear cholesteatomas
| Project/Area Number |
09470373
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Otorhinolaryngology
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| Research Institution | Nagasaki University |
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Principal Investigator |
KOBAYASHI Toshimitsu Nagasaki University, School of Medicine, Professor, 医学部, 教授 (80133958)
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| Co-Investigator(Kenkyū-buntansha) |
KANDA Yukihiko Nagasaki University, School of Medicine Hospital, Assistant, 医学部附属病院, 助手 (20264244)
NAKAO Yoshiaki Nagasaki University, School of Medicine Hospital, Lecturer, 医学部附属病院, 講師 (40188884)
SHIGENO Koichiro Nagasaki University, School of Medicine, Assistant Professor, 医学部, 助教授 (10162588)
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| Project Period (FY) |
1997 – 1998
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| Keywords | cholesteatoma / epidemiology / patulous eustachian tube / labyrinthine fistula |
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| Research Abstract |
(1) Epidemiological research on the incidence of middle ear cholesteatoma was conducted based on the questionarres directed to the otolaryngologists in Nagasaki Prefecture. The study revealed that the incidence of middle ear cholesteatoma among Nagasaki Prefecture habitant can be estimated as 4.44 per every 100,000 population per year. This figure was similar to the one we previously obtained from the study conducted in Miyagi Prefecture in 1994 and 1995. This suggests that the incidence of middle ear cholesteatoma as estimated from the surgical cases in Japan is about 4 per 100,000 population per year.
(2) Familial onset of middle ear cholesteatoma and other related middle ear diseases was investigated. Among the 18 families (40 members) in which a patient with cholesteatoma was confirmed by surgery, 10 persons from 7 families were revealed to have middle ear pathology, such as atelectasis of the tympanic membrane, attic retractions, etc..
(3) Incidence of association of the patulous eu
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stachian tube in cholesteatoma was about 30-40% of all cholesteatoma cases. Bases on this background, a new surgical approach to the patulous eustachian tube was developed by us and performed in 22 cases (30 ears). The success rate of the surgery was calculated as 73% (11/15) for patulous eustachian tube uncomplicated with middle car diseases other than patulous tube and 93% (14/15) in ears complicated with middle ear diseases.
(4) Labyrinthine fistula is the most frequent complication of the middle ear cholesteatomas. The interruption of the semicircular canals was experimentally conducted on the guinea pig. Tue interruption of the 3 semicircular canals did not cause major decrease of the cochlear potentials, however, when suction was applied to the one open end of the semicircular canals, they decreased drastically. This decrease was enhanced when the other ends of the suction site was dry. In constrast, when the other ends were covered with saline solution, the decrease of the cochlear potentials was less prominent. This study implies that when manipulating the labyrinthine fistula one should avoid direct suction, and use irrigation of saline solution. Less
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