Open Source Rapid Manufacture

Comment

Comment by Wolf Schweitzer on November 9, 2010 at 10:55pm

http://clinicaltrials.gov/ct2/show/NCT01155024


Clinical Evaluation of Direct Manufactured Prosthetic Sockets

This study is currently recruiting participants.

Verified by Ohio Willow Wood, September 2010



Detailed Description:

Many members of the Armed Forces and civilians are in need of prosthetic devices due to amputations resulting from gunshots, bombings, vehicular accidents, and other traumas. As the number of amputees increase at a high rate, the limited number of certified prosthetists is finding it harder to satisfy the patient demand. Therefore, the overall goal is to provide the Orthopedic & Prosthetic (O&P) industry with a tool that accommodates the increasing prosthetist to patient ratio and still provide acceptable product quality.

The practice of creating prosthetic sockets by the plaster-casting of amputees' residual limbs has been around for decades but continues to be the most commonly used method for the shape capture, modification and fabrication of prosthetic sockets. Using this traditional plaster-casting approach has many limitations that can now be overcome through the use of technology.

With the advancing developments in Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) technologies over the past ten years, it is now possible to completely replace the plaster-casting approach with handheld, portable scanners.

While this current CAD/CAM approach certainly creates substantial efficiencies in the clinical aspects of creating the prosthetic socket, the actual manufacturing of the prosthetic device continues to rely on the use of a positive model and a lengthy manual fabrication process.

The continuing development of direct manufacturing technologies may serve as the final piece in the effective utilization of CAD/CAM in the care of prosthetic and orthotic patients. Direct manufacturing provides a means to quantify alterations and accurately reproduce prosthetic sockets. Additionally, direct manufacturing has the potential to reduce time, cost, and waste, as a result improve the quality and care ability to patients.

This study will compare two fabrication techniques for diagnostic and definitive sockets: manually fabricated (positive model technique) and direct manufactured (experimental).

Contacts and Locations
Please refer to this study by its ClinicalTrials.gov identifier: NCT01155024

Contacts
Contact: Kathy Kennedy (740) 869-3377 kathyk@owwco.com

Locations
United States, Ohio
Ohio Willow Wood Recruiting
Mt. Sterling, Ohio, United States, 43143
Contact: Mitch Neff 740-869-3377
Principal Investigator: James Colvin, M.S.

Comment by Wolf Schweitzer on November 8, 2010 at 5:50pm

Please expand on why exactly 3D scanning and rapid prototyping is the better way of building prosthetic sockets. I am a complete fan of 3D surface scanning, we use it and build statistical shape models from 3D data and I really love it - but for this application I see some open questions.

Here are my assumptions and I would be interested to see where they would rank in your lists of considerations:

1) My stump has hundreds of various shapes. My stump is bones, a bit of subcutaneous fat, there are some flabby muscles and a bit too much skin as the stump shrank. That, as far as I know, is entirely normal so we assume other amputees are also like that. However, there is one particular shape that my stump should *assume* for a good prosthetic socket. That is, a compressed shape. Here is why: congestion is a frequent and typical stump problem; my stump gets congested when it hangs freely, due to that circulation gets worse, stump pain and phantom pain get a lot worse and in consequence, compression is the best pain prevention I can ever get. Secondly, a peculiar extra pressure of the socket makes it easier for me to use rotation of my stump and transmit that on my arm. So in order to model my deformable stump into the correct shape that it must assume inside the socket, the cheapest and fastest way in my experience is to get an experienced prosthetist to use plaster cast, wrap my arm, squeeze it the right way and a few minutes later when the cast has gotten hard, slip out of it and that's it. So, to have an experienced prosthetist work on the correct shape with his hands has good reasons. These are behind the question "why things are done the way they are done". Please explain what is being scanned for your project, and how do you determine that that is the correct 3D shape for prosthetic socket making.

2) Material. The forces that I transmit over my arm stump and onto the prosthetic adapter parts (pin lock, wrist, terminal device) are relatively large. The measure are current commercially available parts. I have killed parts within weeks that other people did not damage in years. I have terminated parts within seconds that other people lived with for months. So, the socket has to be rather durable. I find that a laminated structure, be it expoy or carbon fiber, is a good choice. These have good tensile and compressive strength. However, materials used for rapit prototyping may be relatively brittle - unless you spend money on them, real money. Or unless you make them bulky and thus heavy. I once tried to get an estimate to get a particular 3D hand shape built from a very robust plastic - the sucker would have cost me 5000 US$. So, with that, effort / time of an experience prosthetist, well chosen laminated materials, et cetera would add up to about 2500$ in maximum. In other words, the current conventional way has some real good reasons why and how it came about. So I wonder how the material / price question is assessed and how it is compared, technically, to performance indicators of conventional prosthetic socket making.