Dog Can Walk Again Thanks To 3D Printing

Check this out! Dog Can Walk Again Thanks To 3D Printing

"Another day, another animal given a new lease on life thanks to 3D printing. This time it’s Derby, a dog born with deformed legs who, with the help of some folks at 3DSystems, now runs alongside his owners with gleeful abandon. Derby’s front legs have been augmented with two blade-like attachments that Who’s-a-Good-Boy uses to run and scamper."

Bloopers: "Weight-ing" for the shanks to break! Cinder block fun times

Watching a cinder block fall in "de-feet"

“Metal-ing” with the weight distribution!

This lovely balancing act fell with a BANG not a minute after these pictures were taken.

Research Update (12/8/14): New Designs (some, even printed!)

Original Bio-Mimic Pylon (Left View)

Original Bio-Mimic Pylon (Angled View)

Secondary Bio-Mimic Pylon (Angled View)

Secondary Bio-Mimic Pylon (Left View)

Doubled Banded
Bio-Mimic Pylon (Left View)

Doubled Banded
Bio-Mimic Pylon (Angled View)

The intent of these designs is to mimic the natural flow of the leg and hopefully spread the pressure out better than a basic straight design. After consulting with my supervisor on the earlier bowed design (this design will not be printed. After designing and seeing the first set of parts print, it became apparent that this design is too bulky, both in weight and size, for practical application), he suggested designing a limb in this direction. Inspiration came from images on this site.

The series of events since the last post occurred chronologically as follows: 

• The first set of pylons (already posted) were designed,
• the straight elliptic pylon was printed, the first true bio-mimic pylon was designed,
• the bio-mimic pylon was printed at a percentage so as to copy the size of the other pylon (it was overshot and the bio-mimic pylon was slightly smaller),
• it was realized that the bows of the original bio-mimic pylon are on the wrong the axis of the ellipse (perpendicular to the minor axis rather than the major, which matches natural design better) and the pylon was not useful do to my accidentally including an ankle component, which is made superfluous by foot attachments,
• the second bio-mimic pylon was designed with the bow perpendicular to the major axis without the intent of production (this design was made primarily for cataloguing, creating a template for future designs on which to build, and visualization),
• the double banded pylon was designed,
• the first produced pylon was qualitatively evaluated under impact; it was determined an elliptic straight pylon of 16cm at 10% in-fill can withstand impact up to 3500-4000 N of pressure for showing serious damage,
• the double banded pylon and the elliptic straight pylon were printed at 10% in-fill with percentages that would produce pylons of approximately 20cm,
• the double banded pylon experienced a printing failure and was reprinted at 20% in-fill.

As you can see from the link and the first four pictures, I got lost in designing and forgot about actual functionality of the product. The first two bio-mimic legs are pretty much a waste due to them extending to ball of the ankle. This error was considered when designing the double-banded pylon.

The reasoning behind these designs (and some sketches for future designs) was the natural design of human legs externally (they match the outlines of the calf muscle, which may result in greater aesthetic appeal) and the structures of the tibia and fibula with respect to one another. The latter is why the central column in all three designs does not have a static circumference; rather, it's thin in the middle and largest at the top and base.

Qualitatively determined by just holding the two existing parts, is that the double banded pylon (20%) is much stronger than the elliptic straight pylon (10%). It is hard to judge whether this is solely due to the difference in in-fill (I am going to have the straight pylon printed with 20% in-fill next) or it could be due to either the presence of banded or a central column with dynamic radii.

The next step, which will occur before Thursday, is to test the pylons by applying sustained pressure (rather than impact). This will by done resting cinder blocks (weighing approximately 160 N each, which is approximately 36 lbs) and other modes of weight while the pylon is fixed to a force plate. The force plate will connected to a data logger, which will record all of this. Weight will be applied to the pylon until it shows signs of damage.

Establishing the Problem: Rationale

There is unmet need for transtibial prostheses for persons <18 years of age that are capable of growing with the minor; that is, the prosthesis is either easily replaceable or adjustable beyond what is currently provided, which must be replaced every 1 to 2 years when the child grows beyond the prosthesis’ range of adjustment or wears out the limb with continuous stress. A child will need frequent replacement of a transtibial prosthesis for two primary reasons: growth and activity.

According to the CDC and researchers at Worcester Polytechnic Institute, children between ages 2 and 14 may grow 5-10 cm per year. Although conventional transtibial prostheses are capable of adjustment--endoskeletal shanks can be adjusted by changing the internal piping, exoskeletal shanks can be adjusted incrementally with the addition of shims by a prosthetist, and shoe insert may be added for both types of shanks--these adjustments have their limitations, and the child will require a new prosthesis given how rapidly they grow, both in height and weight.

People under 18 years of age also tend to be very active, putting more strain on their joints and requiring a higher range of motion. With continuous use, either sustained moderate pressure (i.e. walking, standing, etc.) or intermittent pressure (i.e. jumping, running, etc.), the prosthesis will exhibit a weakened shank, wear on movable components, and a less aesthetically pleasing external finish.

Frequent replacement of the prostheses should not be a problem; replacements do exist for all four components of a below-knee prosthesis (ankle-foot assemblies, shanks, below-knee sockets, below-knee prosthetic suspensions), but patients and families face financial restrictions in most cases. Prostheses are expensive (usually upward of $5,000) and frequent replacement is burdensome. Patients who require frequent replacements often deal with restrictions from their primary third-party payer. In some cases, children are denied financial reimbursement from insurers and must decline a prosthesis that their families can’t afford.

Initials Concept Designs (printing soon)

First designs! These are going to be the first three designs printed. The next one to come will probably be something simulating the natural tibia-fibula design.

Adult Elliptic Pylon

Adult Elliptic Pylon
(with notes)

Adult Circular Pylon

Adult Circular Pylon
(with notes)

Adult Circular Straight Pylon
with Bows

Adult Circular Straight Pylon
with Bows (with notes)

Adult Circular Straight Pylon with Bows (cross section)

Open Hand Projects

If you're interested in prosthetic hand research, check out these articles:

http://www.eng.yale.edu/grablab/openhand/
http://www.openhandproject.org/
https://www.indiegogo.com/projects/the-open-hand-project-a-low-cost-robotic-hand

Cool Article: Kids outfitted with new hands made on 3-D printers

Within the past year, a child, Griffin Matuszek, was fitted with a function 3-D printed hand!
Read the article to find out more. This serves as proof that 3-D printing has effectively helped children with limb deficiencies. However, there is a big difference between a hand and a leg. While a hand is more mechanically intensive, a leg is under more physical stress due to weight. A hand is a good place to start, but further research must go into the limitations of 3-D material.

Also check out this article published by Fox News to learn more about Griffin Matuszek's story. This article goes a bit more into the potential for 3-D products in the medical industries, both the pros and cons. Check it out!