Senior Design Project
Self-Adjustable Prosthetic Socket for Diabetic Patients on Dialysis
By applying design and engineering principles, my team addressed and developed a solution to a medical unmet clinical need. We focused on a patient group of diabetic amputees who experience cyclic weight fluctuations, often due to dialysis treatment. These patients seek easy, reliable, adjustments to their prosthetic socket when their residual limb changes volume throughout the day- so we met this need with a socket solution.
Ethnography
I met with and conducted an interview with Dr. Goeran Fiedler, a professor for the prosthetics and orthotics program at the University of Pittsburgh. In this meeting we discussed how ciritical our unmet need is and he supplemented our design ideas as well as providing further ones. I performed a one-minute pitch during class to hear ideas from classmates.
Design Idea
Through killer experimentation, a design idea was finalized in dial technology that would allow quick adjustability for diabetic patients experiencing weight fluctuations. My idea stemmed both from meeting with Benedict, a teacher in the emergency medicine program at Pitt, as well as watching family members make use of Boa dial technology in real life, I saw how applicable it could be and approached my team with the idea.
Prototyping
Ski-boot design sketch
Ski-boot design paper and foam core model
Semester 2 Fabrication Efforts
3D-printed boa dial track
Molded residual limb, vacuum-formed ABS, and assembled components with compression sleeve
Design Freeze Materials List:
-Low Density Polyethylene
-3 Boa dials
-PLA filament (3D printed tracks) and dial bases
- Heat inserts and screws
Made plaster positive mold of our patient models residual limb
Vacuum formed low-density polyethylene around positive mold
Cut 3 posterior slots for adjustability with prosthetics/orthotics dremmel
Grinded down edges
3D printed tracks and basees for the Boa dials and attached them use soldered heat inserts
Reference photo of final test socket
Documentation
Lead document control orders and applied time and skill into
several documentation areas:
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1. Regulatory Strategy:
Provided classification information, following CFR 830.3420, external limb
prosthetic component, FDA guidance. Our device would be exempt from
the premarket notification procedures (510(k)).
Wrote a pre-submission application in compliance with FDA guidance
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2. Initial Hazards Analysis:
Took on responsibility for testing for noting and testing for hazards
during killer experimentation and with our final prototype.
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3. Risk Summary:
Analyzed risk of the hazards identified and shared risk mitigation strategies.
Asserted new probability and risk post risk mitigation proposals.
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4. Product Design Specification:
Wrote thorough design specifications in the following categories:
dimensional and physical, material, functional & performance, and risk
management specifications and made changes as our design shifted.
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FDA guidance for regulatory pathway
PDS example
Verification and Validation
Verification Testing:
7 total verification test: Resonsible for Ver-2 (Total Weight) and Ver-4 (Cleanability)
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Ver-2: Total Weight:
Acceptance Criteria 550 +-5g
Successful Test
- Wrote protocol, conducted test, wrote test report
Ver-4: Cleanability
Acceptance Criteria: No test perspirant residue
Successful Test
- Wrote protocol, conducted test, wrote test report
Validation Testing:
Clinician Interview - Responsible
Focus Group Interviews
Usability Testing - Responsible
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Over the course of several months, my team and I planned our validation efforts. We coordinated 3 different validation sessions: a usability test with our patient model, a focus group to conduct personal interviews about our adjustable socket, and a clinician interview.
I was able to test VAL-1 (Adjustability) and VAL-2 (Ease-of-use) in a usability study. VAL-1 (Adjustability) failed because our patient model was unable to adjust the dials tight enough for a comfortable and effective fit, but VAL-2 passed as our adjustability mechanism was easy to use.
Finally, I conducted an interview with a Prosthetics Clinician who validated VAL-7 (Demonstrability), and agreed he could effective communicate the use of our device to his patients.
Usability Validation Testing
Swanson School of Engineering Design Expo
Fall 2023
Spring 2024
2nd Place in the Bioengineering Category
