THE MECHANICAL STABILITY OF
ALLODERM FOR MYRINGOPLASTY
Ian Scott
Medical Biophysics
April 7th, 2010
The Middle Ear
The function of the middle ear is to transfer acoustic energy from air
in the ear canal to the fluid within the cochlea
Myringoplasty
• Acute infections of the middle ear are extremely
common, especially among children and infants
• These infections can lead to perforations of the
eardrum result of fluid and pressure build up
• Myringoplasty or Type 1 tympanoplasty, is the
reconstruction of the eardrum, and is a very
common surgery occurring in 5.4/10,000 in a
population
Graft Materials
• Autograft
– Cartillage
– Fascia
• Allograft
– Alloderm
Advantages of AlloDerm
• Decreased operating room time
– Eliminates need for additional incisions
• Decreased risk of morbidity
• Allows for surgery when autologous tissue
supply is exhausted
– Revision myringoplasty surgeries are often required
Alloderm
• Acellular cadaveric tissue
made by LifeCell Corp
(Branchburg, NJ)
• Treated with a decellularizing
agent eliminating the
possibility of rejection
• Main structural components
form a scaffolding
Functional Requirements
• Mechanically stable in presence of large
pressures
• Similar vibratory characteristics to the
eardrum
• Similar Young`s modulus and thickness to the
eardrum
Objective
• Measure the response of AlloDerm to large
static pressures up to 4kPa.
Methods
Results
Fig. Pressure deformation curves for varying static pressures
Results
Discussion
• AlloDerm showed stability up to 4kPa as
required
• Non-linear relationship shown between static
pressure and deformation
Conclusion
• AlloDerm is stable up to 4kPa of applied static
pressure
• A non-linear relationship is shown between
applied static pressure and deformation
Future Work
• Test on multiple samples to quantify variability
in response
• Measure the vibratory characteristics in
application to sound transfer
• Find Young`s modulus through the use of
indentation tests to verify the required
``stiffness``
Acknowledgements
• Supervisor
– Dr Hanif Ladak
– Dr Sumit Agrawal
• The Lab
– Xiaochuan Ma
– Govind Rehal