Device Overview:

The unmet clinical need that we chose for our project revolves around stroke patients who suffer from foot drop and must now wear an Ankle Foot Orthosis (AFO) brace for support. This unmet need was presented to us by Occupational Therapists (OTs) from UPMC and Pitt SHRS. These patients also typically experience hemiparesis and other limitations to their mobility and dexterity, so they have a difficult time donning their shoes. This limits their independence, and often acts as a barrier to discharge from the hospital. To solve this issue, we designed a portable device that aids in shoe donning with an AFO brace and is designed to be easy to use for those with limited mobility, dexterity, and/or hemiparesis. 

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The AFO Shoe Donning Assist Device is intended for use to assist in the donning of shoes to improve ease-of-use of donning for patients with impaired mobility and/or dexterity. It is indicated for use for patients who use an AFO brace to treat foot drop secondary, not only to strokes, but any muscular, neurological, or neuromuscular degenerative diseases, or those who use an AFO for any other reason. It is also indicated for patients who do not experience cognitive defects secondary to their disease, which would impact their capacity for new learning, and for patients who have the physical capabilities to sit upright in a chair and maintain balance while using the device.

 

The features of this device include:

• A shoe strap to constrain the shoe during donning

• A non-slip platform to reduce shoe slipping and movement during donning

• A non-slip base to reduce device slipping on floor during donning

• A tongue clip to hold open the tongue of the shoe

• Adjustable angles to accommodate for different users' ranges of motion

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PROTOTYPING:

Low Resolution Prototyping: 

Our low resolution prototyping efforts consisted of conceptual sketches for our initial solution ideation. This was then followed by developing minimum viable prototypes, with an established minimum viable feature set, from foam core.  This was assembled via hot glue and push pins, and the initial iterations of our features were made from velcro straps, D-rings, pipe cleaners, and clothespins. 

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Medium Resolution Prototyping:​

Our medium resolution prototype brought us to the wood shop. For this iteration, we built the platform from laser cut hardboard and CNC-cut MDF. The teeth were constructed of MDF. This prototype had a re-designed strap, that I drove the design and fabrication of, an updated tongue clip, and a new design of the teeth for the angle adjustability. The designs of these feature sets were determined after killer experimentations were conducted with the low resolution prototype.

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High Resolution Prototyping:​

Our high resolution prototype involved taking the components from our medium resolution prototype and upgrading the designs and the materials. The device platform and base were constructed out of birch plywood, and the joints, teeth, and dowel rods were made of stainless steel. There were not many design changes, as the focus was to produce a slightly modified version of the medium resolution prototype, with the main focus being on the upgrade in the quality and durability of the materials. This design was not yet frozen and we planned to develop at least one more prototype before  V&V.

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Design Freeze:

​Our frozen design and resulting devices were fabricated after we took the high-resolution prototype to OTs and conducted a focus group to obtain feedback on the design of the device and its components, as well as collecting usability data to see if the OTs were able to use the device. The device was constructed out of the same materials as the high-resolution prototype. The biggest changes involved the strap, whose design I was responsible for finalizing and fabricating. Additional minor changes were made to the platform, including the addition of a bumper, and the dowel catch to improve the stability and storability of the device. 

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DOCUMENTATION EFFORTS:

Another part of the course, aside from product design and fabrication, was documentation in the style that the FDA expects to see. This documentation began with regulatory documents to determine the proper pathway for our device. This was followed by delineating user needs to inform design inputs, hazard and risk documentation, traceability documents, and V&V test plans. For the V&V testing, my particular documentation focused on the Validation documents (plan, protocols, reports).  Below are the documents that the team developed over the course of the two semesters, with the italicized being documents that I heavily contributed to (and for underlined documents, completed completely individually):

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• Use Case - Patients ; Use Case - Clinicians

• User Needs

• Regulatory Strategy

• Initial Hazards Analysis 

• Fault Tree Analysis

• Failure Modes and Effects Analysis

• Risk Summary

• Verification Test Plan

• Validation Test Plan

• eQMS

• Traceability Matrix

• Green Light Guru - Design Controls Matrix

• SOPs and Forms

• IRB Application, Protocol, and Supporting Documents​

• Patient & Clinician Validation Test Protocols (x2)

• Patient & Clinician Validation Test Reports (x3)

• Patentability & Infringement Assessments

• FDA Pre-Submission

• EU MDR Technical Documents

  • Annex II - Information Supplied by the Manufacturer​

• Design EXPO Poster (x2)

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Verification & Validation Testing:

Another component of this course, and the FDA product development and approval pathway, is V&V testing. Verification consists of conducting tests to ensure that the product meets the outlined design specifications. Validation consists of conducting human subjects testing (with IRB approval) to ensure that the user needs are met. While the rest of the team was tasked with Verification testing on the device, I was responsible for designing, recruiting for, and conducting the Validation testing, along with the data, root cause, and residual risk analyses for the reports and to inform if our device was Validated based on the pre-defined acceptance criteria.  

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I first developed a Validation plan, which provided a high level overview of the Validation tests that I was going to conduct. It provided information on the user needs, as defined in our User Needs documentation, and how each of these needs was to be tested. I used my human factors engineering experience to help me to design a usability-focused session with our patient demographic and, initially, a focus group session with our clinician demographic. The Validation Plan includes the acceptance criteria set to validate that our device meets the user needs of our two user archetypes. I also included recruitment criteria and summaries of the two validation tests. This informed the test protocols that I developed, one for the Patient user group and one for the Clinician user group. Each protocol consisted of the methodology, procedures, and equipment required for each study. Each protocol also outlined the acceptance criteria, as well as the justification as to how this acceptance criteria was determined. To develop these acceptance criteria I referenced ANSI/AAMI HE75,  IEC 62366-1, and FDA Guidance documents for Human Factors Engineering.

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The Patient Validation test was designed as a usability study, where the patients were taught how to use the device and then were asked to use the device to don their shoe. One of my other team members would demo how to use the device, and then I would observe and grade the participants on their use of the device, noting any errors, based on the pass criteria outlined in the protocol. They were also tasked with donning their shoe using their normal method so that the ease of using the device compared to typical donning could be evaluated. Since this study was limited by the constraints of the scope of the scope of the class and our IRB, I only tested three stroke patients, all who were at least a year into their recovery. The test population was slightly different than the one that would be using our device (true users would be earlier in their recovery), which led to some of the errors that occurred during testing to be test artifacts and a result of our participant population, most of which whom would be contraindicated for device usage. However, as I concluded in the report that I drafted, it was found that all eight of the patient user needs were met and validated (within the scope of the class) as a result of this study and the resulting root cause and residual risk analyses.

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I also was tasked with running the OT Validation test. This was originally designed as a focus group. However, after the test was conducted, it was found that this was not an appropriate method to collect data from the OTs, since they also would be using the device in a hands-on fashion to train patients, so I revved the protocol and Validation plan to change the study to be a usability study. For this study, the OTs were trained on how to use the device, then were asked to explain to me how to use the device and to highlight all of the features, as if I was a patient they were training. I would observe and grade the participants on their demonstration of the device, noting any errors, based on the pass criteria outlined in the protocol. As I concluded in the test report for OTs, it was found that all three of the OT user needs were met and validated (within the scope of the class) as a result of this study and the resulting root cause and residual risk analyses.

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OTHER INDIVIDUAL CONTRIBUTIONS:

• IRB Application: I was in charge of compiling, completing, and reviewing the IRB application and all supplemental documents and research for our Patient Validation study. This included designing the study, developing all study materials (including protocol, interview questions, recruitment materials, data management plan, etc.), completing the IRB application, coordinating with the IRB reviewer to ensure application approval, and designing the validation tests to adhere to the way it was laid out in the IRB application. Additionally, as a result of a shift in testing plan from conducting the Validation studies at Pitt to conducting them at rehab centers, I had to, in February, submit an amendment to our original IRB that was approved in December. 

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• Coordinating Risk Reduction Effort: Thanks to my FDA human factors validation experience from my co-op, I had experience with conducting risk reduction activities, including, but not limited to, risk identification, risk mitigation, and residual risk analysis. Therefore, I was tasked with driving the risk identification and mitigation efforts for this project. While everyone helped on the various documentation, I was particularly in charge of the Initial Hazards Analysis and the eQMS documents. Apart from the documents, I was responsible for ensuring that all of the risk and hazard analysis documents corresponded with each other and that any risk was covered in at least one document. This role carried on into the second semester, where I was in charge of conducting the residual risk analysis on the Validation test data to determine if the user needs were met for each user group.

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• Strap Ideation and Fabrication: A specific contribution that I had to our prototyping and fabrication efforts was the design and fabrication of a strap to constrain the user's shoe in place. For the low-resolution prototype, this consisted of different iterations of velcro straps and D-rings that were hot glued to the foam core model in various fashions. The best strap orientation and design was determined via killer experiments. Then, for the medium resolution prototype, I was in charge of hand-sewing a strap together, from pieces of elastic and velcro, into the style we had determined worked best. After this, I was responsible for finalizing the strap design and material choice for our design frozen device. Then I was in charge of fabricating the final "PE" strap, out of velcro straps and including a blue pull-tab indicator, for our two final devices for testing. 

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• Document Control SOP: One emphasis of the class was to understand SOPs and forms and to develop our own to govern our design, re-design, documentation, fabrication, etc. We created a handful of SOPs and forms in this class, including a Change Management SOP, Document Control SOP, and Quality Management SOPs. The forms we created included an Engineering Change Order Form and a Document Change Order Form. While I helped develop all these forms, I contributed heavily to the Document Control SOP.  Thanks to my co-op experience in R&D for a medical product company, I have extensive experience with Document Control. I used this experience to create the Document Control SOP that our group used to name and control all DHF-associated documents for this course.

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• Scribe/Notetaker: Since one of the main forms of communication with the FDA is through meeting minutes, we as a team decided to take meticulous notes at all of our meetings (with Dr. Gartner, our mentors, during team meetings, etc.), so that we could have an accurate depiction of the events, conversations, and outcomes of each meeting. It was my role to ensure that detailed, succinct notes were taken at every meeting and to ensure that they were then reviewed by the team and sent to the respective second party for further review and clarification. If clarification was needed, it was also my responsibility to update the meeting minutes accordingly to reflect any changes.

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