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Stenosis-cont.
As the percentage of the stenosis increases,
the developing stress increases.
Stents types
The self-expanding metal stent has higher
stresses than the balloon metal stent.
The stresses at the studs areas are 2 times
higher than at the smooth region of silicon
stents
2012
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2
Geometry-cont.
The three investigated tracheae:
•
Case a: healthy straight
•
Case b: stenotic with 50% obstruction.
•
Case c: stenotic with 70% obstruction.
For each type of stent a variety of
geometries were built and different
mechanical parameters were modified.
Trachea models: (a) healthy trachea, (b) 50% obstruction,
(c) 70% obstruction, (d) fully trachea assembly
Airway stents and trachea models
Stress analysis of Airway stents
Student name:
Dikla Kesner
Department:
Medical Engineering
Advisor name:
Dr. Sara Naftali
Coughing
There is a difference of 5% between the
maximum stresses during coughing
compares to the normal case.
Stenosis
4. Results
Longitudinally distributed stresses
on 50% stenotic trachea with varied stents
Stress on the trachea in a longitudinal direction during
coughing and normal condition with silicon stent
The developing stresses on metallic stents
have significantly large values with 3 orders
of magnitude than the stresses that develop
on silicon stents.
The low stresses found in silicone stents
may indicate of weak contact with the
trachea which can explain their known
migration along the airway paths. The studs
may reduce the migration risk.
According to these tests, the additional
radial pressure on the trachea during
coughing, has no significant effect on the
results of the stent's stresses.
5. Discussion and
Conclusions
Stress on the trachea in a longitudinal direction
of smooth silicon stents and balloon stents
with 0%, 50% and 70% stenosis
Contours of equivalent stresses on metal stent
Self-expanding uncover inserted on stenotic trachea