College - Author 1
College of Engineering
Department - Author 1
Biomedical Engineering Department
Degree Name - Author 1
BS in Biomedical Engineering
College - Author 2
College of Engineering
Department - Author 2
Biomedical Engineering Department
Degree - Author 2
BS in Biomedical Engineering
College - Author 3
College of Engineering
Department - Author 3
Biomedical Engineering Department
Degree - Author 3
BS in Biomedical Engineering
Date
3-2023
Primary Advisor
Christopher Heylman, College of Engineering, Biomedical Engineering Department
Abstract/Summary
The key factors in the redesign of this part include the use of biomaterials, the redesign of the part geometry to include these biomaterials, and the proposition of production scale manufacturing methods suitable for these redesigns. The choice of biodegradable material was guided by previous literature, during which we found the PLGA polymer used in similar predicate devices with a biodegradability timeline similar to our goals. The model of coupler serving as the inspiration for the redesign utilizes two very strong but bioinert materials, polyethylene, and stainless steel. These high strength materials can withstand much greater forces than the biodegradable bulk material chosen for the redesign, so features of the old design were modified for robustness. This included to realize this new design on a production scale, the two most promising possibilities include injection molding with the PLGA polymer or additive manufacturing using stereo lithography printers and biodegradable resins. The commonality of these two processes is the ability to make complex shapes while retaining isotropic materials in the final part, which is essential for the strength of small features such as the pins.
Key customer requirements for anastomotic procedures include successful attachments of vessels and low rates of dehiscence. These requirements are related to our coupler by successful attachment rate, max force withstood by coupler before assembly separates, max forces withstood by vessels before ripping.
Different models of the coupler device were tested in assembled orientation with one blood vessel surrogate engaged. In both models, tensions upwards of 100N were experienced without a signal failure of the pins. This demonstrates that the pins are exceptionally stronger when assembled into the opposite coupler than when unengaged.
Another factor in the improvement of the device is the time taken to film an implementation of the device using dissected cow arteries. The first round of prototypes required several people to affix the coupler and blood vessels and required additional processing of the cow arteries in the form of puncturing pilot holes for the spikes. Overall, the procedure took about an hour to perform. The latest model of prototypes was operated on in only a half hour and required only one person to perform the procedure. The improved placement and orientation of the spikes allow for much easier puncturing of the arterial wall for smoother attachments.
URL: https://digitalcommons.calpoly.edu/bmedsp/166