Stiffness changes of the tympanic membrane in otitis media
Author: Larsson, Christina
Date: 2002-05-24
Location: Föreläsningssalen på entreplanet i CMM-huset, Karolinska Sjukhuset, Stockholm
Time: 9.30
Department: Institutionen för klinisk neurovetenskap / Department of Clinical Neuroscience
Abstract
Acute purulent otitis media and otitis media with effusion, are common
diseases in childhood. Years later some of the children will get
"complications", such as retraction pockets and cholesteatoma, that often
need advanced surgical treatment. Our hypothesis is that already a short
period of inflammatory middle ear disease can cause a loss of stiffness
in the tympanic membrane. Such a stiffness loss may predispose for the
late complications. In previous experimental studies, stiffness changes
were shown to develop in the pars tensa of the tympanic membrane during
otitis media. Retraction pockets are, however, often found in the pars
flaccida, which differs greatly from the pars tensa regarding morphologic
structure.
The acoustic stiffness properties of the tympanic membrane were studied
in early stages of experimental cholesteatoma in the gerbil. The
measurements were performed with an invitro tympanometry model. The
results showed an increased acoustic stiffness. This acoustic stiffness
change was correlated to a pathological thickness increase of the
tympanic membrane. The increase of acoustic stiffness contrasts to
previous results showing a loss of mechanical stiffness in the same
disease model. This difference emphasizes that acoustic and mechanical
stiffness are governed by different structural properties. Awareness of
this may be important searching for better surgical methods and materials
in middle ear reconstruction.
A projection moire interferometry model was designed in order to enable
measurements of the mechanical stiffness of the pars flaccida in the
gerbil. Moire interferometry is a noncontacting optical method with which
the shape and displacement of an object can be measured. Peak
displacement versus pressure was used as a measure of mechanical
stiffness. The mechanical stiffness properties of the healthy pars
flaccida as well as of the pars flaccida during purulent otitis media and
otitis media with effusion were assessed. The border of the pars flaccida
was almost circular and the displaced pars flaccida had the shape of a
sphere cap. Therefore the volume displacement could be calculated as
well. In the peak displacement measurements a loss of mechanical
stiffness was assessed during purulent otitis media and otitis media with
effusion already within a few days. This loss of stiffness may be
persistent and may predispose for future retraction pocket formation and
cholesteatoma development.
List of papers:
I. Larsson C, von Unge M, Bagger-Sjoback D (1999). "Tympanic membrane changes in experimental cholesteatoma in the gerbil. " Am J Otol 20(3): 309-16
Pubmed
II. Larsson C, von Unge M, Dirckx JJ, Decraemer WF, Bagger-Sjoback D (2001). "Displacement pattern of the normal pars flaccida in the gerbil. " Otol Neurotol 22(4): 558-66
Pubmed
III. Dirckx JJ, Decraemer WF, von Unge M, Larsson C (1997). "Measurement and modeling of boundary shape and surface deformation of the Mongolian gerbil pars flaccida. " Hear Res 111(1-2): 153-64
Pubmed
IV. Dirckx JJ, Decraemer WF, von Unge M, Larsson C (1998). "Volume displacement of the gerbil eardrum pars flaccida as a function of middle ear pressure. " Hear Res 118(1-2): 35-46
Pubmed
V. Larsson C, Dirckx JJ, Decraemer WF, Bagger-Sjoback D, von Unge M (2002). "Pars flaccida displacement pattern in purulent otitis media in the gerbil." Otol Neurotol (Submitted)
VI. Larsson C, Dirckx JJ, Bagger-Sjoback D, von Unge M (2002). "Pars flaccida displacement pattern in otitis media with effusion in the gerbil." (Manuscript)
I. Larsson C, von Unge M, Bagger-Sjoback D (1999). "Tympanic membrane changes in experimental cholesteatoma in the gerbil. " Am J Otol 20(3): 309-16
Pubmed
II. Larsson C, von Unge M, Dirckx JJ, Decraemer WF, Bagger-Sjoback D (2001). "Displacement pattern of the normal pars flaccida in the gerbil. " Otol Neurotol 22(4): 558-66
Pubmed
III. Dirckx JJ, Decraemer WF, von Unge M, Larsson C (1997). "Measurement and modeling of boundary shape and surface deformation of the Mongolian gerbil pars flaccida. " Hear Res 111(1-2): 153-64
Pubmed
IV. Dirckx JJ, Decraemer WF, von Unge M, Larsson C (1998). "Volume displacement of the gerbil eardrum pars flaccida as a function of middle ear pressure. " Hear Res 118(1-2): 35-46
Pubmed
V. Larsson C, Dirckx JJ, Decraemer WF, Bagger-Sjoback D, von Unge M (2002). "Pars flaccida displacement pattern in purulent otitis media in the gerbil." Otol Neurotol (Submitted)
VI. Larsson C, Dirckx JJ, Bagger-Sjoback D, von Unge M (2002). "Pars flaccida displacement pattern in otitis media with effusion in the gerbil." (Manuscript)
Issue date: 2002-05-03
Publication year: 2002
ISBN: 91-7349-224-8
Statistics
Total Visits
Views | |
---|---|
Stiffness ... | 745 |
Stiffness ...(legacy) | 572 |
Total Visits Per Month
October 2023 | November 2023 | December 2023 | January 2024 | February 2024 | March 2024 | April 2024 | |
---|---|---|---|---|---|---|---|
Stiffness ... | 34 | 14 | 23 | 29 | 17 | 26 | 12 |
Top country views
Views | |
---|---|
India | 237 |
United States | 221 |
Ireland | 112 |
Sweden | 77 |
United Kingdom | 72 |
Germany | 57 |
China | 38 |
Malaysia | 23 |
Australia | 21 |
Canada | 21 |
Top cities views
Views | |
---|---|
Dublin | 77 |
Bengaluru | 20 |
Hyderabad | 20 |
Kiez | 15 |
Seoul | 15 |
Stockholm | 15 |
Chennai | 14 |
Ballerup | 13 |
Ashburn | 11 |
Beijing | 11 |