Chen, Yanfei
(2018)
Design, Parameter Optimization and In Vitro Evaluation of Implantable Medical Devices.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The number of implantable medical devices ranging from dental implants to cardiovascular implants has been exponentially increased in the last decades and various materials including metallic materials and polymeric materials are used in medical device manufacturing. In metallic materials, nitinol is widely used due to its superelasticity and well-known biocompatibility. Finite element modeling (FEM) along with in vitro and in vivo is being adopted to evaluate the medical device performance in patients and optimize medical designs.
In this dissertation, four innovative implantable medical devices were developed and their performances were evaluated using finite element modeling and in vitro testing: 1) ventriculoamniotic shunt for aqueductal stenosis treatment. It has the conduit to drain excessive cerebrospinal fluid (CSF) to lower intracranial pressure in fetal brains and the anchors to prevent the device dislocation during the treatment. The shunt tube design was optimized using computational fluid dynamics calculations. The anchor design was determined with ANSYS Static Structural and the prototype was manufactured based on modeling results. In vitro pressure and flow rate measurement within shunt device demonstrate that the pressure in fetal brain can be reduced by 95.2% while the pressure elevation in amniotic sac is negligible. 2) TFN flow-diverter integrated with flow sensing system for cerebral aneurysm post-treatment monitoring. The flexibility of TFN membrane was investigated using both computational modeling and stretching experiment. As the TFN was wrapped on a flow-diverter backbone with junction points, we evaluated the attachment patterns between a TFN and stent backbone. Finally, micro-scale flow sensor was designed and fabricated based on the computational modeling. 3) compartmentalized stent to isolate the perfusion of the abdominal organs. The fluid dynamics inside the arterial and venous organ perfusion stent (OPS) was analyzed in terms of velocity distribution and wall shear stress (WSS). In vitro pressure difference both in arterial and venous OPS showed that the stent deployment with perfusion flow to the abdominal organs will not generate a significant load on the donor's heart. 4) retrievable stent graft for noncompressible hemorrhage control. The mechanical and biological properties of ePTFE membrane were investigated and the nitinol framed backbone was evaluated in terms of radial force.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
25 September 2018 |
| Date Type: |
Publication |
| Defense Date: |
16 April 2018 |
| Approval Date: |
25 September 2018 |
| Submission Date: |
8 May 2018 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
130 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Industrial Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Implantable medical devices, finite element analysis, in vitro evaluation, endovascular treatment |
| Date Deposited: |
25 Sep 2018 16:06 |
| Last Modified: |
25 Sep 2018 16:06 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/34489 |
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