Helping Hannah: 3D Printer To The Rescue

Helping Hannah: 3D Printer To The Rescue

CREATED Jan 24, 2014

WILMINGTON, Del. (Ivanhoe Newswire) - Children with neuromuscular diseases, like muscular dystrophy, have a hard time moving their arms and doing basic things like eating, playing, or hugging their loved ones. Now, a new 3D printed exoskeleton is helping these kids move in ways they never thought possible.

During her fifth month of pregnancy, Jennifer Mohn was told to prepare for the worst for her unborn daughter.

"They told us to make arrangements for her," Jennifer Mohn, Hannah's mom, told Ivanhoe.

Baby Hannah Faith survived, but was born with a list of health conditions, including arthrogryposis, a disease that affects muscle strength.

"She was just really unable to move," Jennifer said.

Four years later she's making great strides, thanks in part to 3-d printed arms known as the Wilmington Robotic Exoskeleton, or WREX.

Each WREX is constructed of lightweight plastic and rubber bands and can be custom made overnight with the use of a 3D printer.

"If you do the geometry right and you put the bands in the correct place, you can get this floating sensation for a kid," Tariq Rahman, PhD, Senior Research Engineer, Nemours/Alfred I. duPont Hospital for Children, told Ivanhoe.

It's allowing kids like Hannah the ability to move their arms and even flick a rubber band.

"To see her have the ability to reach her arms out, to reach out and grab something is just a really amazing feeling for a mom," Jennifer explained.

Since a 3D printer is used, the customized exoskeletons can easily be made to grow with the child.

The WREX can also be used by children with other neuromuscular diseases or by adults with stroke and spinal cord injury.


BACKGROUND: Arthrogryposis is a term for the development of non-progressive contractures affecting one or more areas of the body. A contracture is a condition in which a joint becomes permanently fixed in a bent (flexed) or straightened (extended) position, completely or partially restricting the movement of the affected joint.  When congenital contractures occur only in one body area, it is not referred to as arthrogryposis but rather an isolated congenital contracture. The most common form of an isolated congenital contracture is clubfoot. When arthrogryposis affects two or more different areas of the body, it is called arthrogryposis multiplex congenita (AMC). The most common form of AMC is amyoplasia.  (Source:http://children.webmd.com/arthrogryposis-multiplex-congenita)

CAUSES: Arthrogryposis is usually developed before a baby is born. Six common causes of this condition are: abnormalities of connective tissue, restricted movement of the uterus, maternal illness, abnormalities of the nerves that connect to muscles, abnormalities of muscle function, and the loss of neurons.  Each of these factors occur while the mother is still pregnant, then symptoms of the condition will appear after birth. (Source: http://www.disabled-world.com/health/orthopedics/arthrogryposis.php)

SYMPTOMS: The symptoms of AMC vary depending on the patient, severity, and location of the condition. In most cases, affected infants have contractures of various joints.  The joints of the legs and arms are usually affected, but the legs are affected more often.  It can also occur in the joints of the elbows, shoulders, knees, wrist, ankles, toes, fingers, and hips. In addition, the jaws and back are also often affected in patients with AMC.  More than 300 different conditions can cause isolated or multiple contractures and the causes, genetics, specific symptoms, and severity of these disorders vary dramatically.

NEW TREATMENT: The Wilmington Robotic Exoskeleton, also known as WREX, is a device made of resistance bands and hinged bars. It is also described as an anti-gravity upper limb orthotics.  It was constructed to help children with little residual strength from muscular and joint disorders to move their arms in space.  The problem was that it was only available for patients under six years old.  Now, researchers are using 3D printing to allow even younger patients to use it.  The use of a 3D printer allows doctors to customize the WREX to each patient.  (Source: Dr. Tariq Rahman) 


Tariq Rahman, PhD, Senior Research Engineer, Nemours/Alfred I. duPont Hospital for Children, talks about a new treatment for children with neuromuscular conditions.

Can you tell us about the WREX?

Dr. Rahman: It is relatively simple. It is constructed of mechanical pieces, links, and rubber bands. If you do the geometry right and if you put the bands in the correct place, then the kids with weak arms can get a floating sensation as if they were in in zero gravity.

And that's important because this is made for children with what kinds of conditions?

Dr. Rahman: Children with neuromuscular conditions such as muscular dystrophy and arthrogryposis, which Hannah has. So these kids have weak limbs, particularly in their arms and their biceps and they have a difficulty moving their hands. The WREX helps them to defy gravity; allowing them to move their arms in space in front of them.

How exactly does it work?

Dr. Rahman:  It is similar to a table lamp or a dentist light except a little more refined, but essentially you can move your hand with very little effort when you have the bands just right.

So, these children have severely underdeveloped muscles. It is really difficult for them to be able to move their arms, correct?

Dr. Rahman: That's correct. They use compensatory movements like putting their elbow up or using their other hand to help them move. Simple things like feeding themselves, is a real chore. So, WREX allows them to move their elbows and hands to feed themselves or flip rubber bands. 

Why is this such a breakthrough?

Dr. Rahman: The technology has been around for years, but we use 3D printing to make this a customizable, light device that can be mounted on a body jacket. So, a kid that struggles to walk can have this mounted on them and can walk. So, that's something novel.

How old does the child have to be to get this?

Dr. Rahman: The youngest, believe it or not, is seven months old 

So, basically what's new about this is your ability to make smaller versions of it to go onto these younger children that have this problem?

Dr. Rahman: Yes, to make them custom and lightweight. 

Can you talk a little bit about some of the problems that children can have? 

Dr. Rahman: Accessing a computer, typing, reading, feeding themselves, scratching their nose, those are issues for these kids. This allows them to do that and in a more dignified way.

Is it giving them that ability to catch up with everyone else?

Dr. Rahman: That's right, yes. We have a related project that's looking at WREXs for small babies and we're targeting their cognitive development through the movement of their arms. If they weren't moving their arms and there was no device to help them, we hypothesize that their development will be delayed. With the WREX, we'll see if their development is improved.

Can you also talk about the 3D printing?

Dr. Rahman:  That is what makes this project unique. It allows us to make parts rapidly and make them customizable to a kid. If we were making this out of traditional metals or aluminum, it would take a week. Now, we can do this overnight and provide it to a kid. We are also looking at the possibility of providing these remotely to other places in the world. So, they can print off their own WREXs and apply them, but that is a ways down the road. 

What's it like for you to know that you're able to help all these kids?

Dr. Rahman: It's great. Just seeing the kids and the parents smile is very fulfilling.

What do you think is most important about this?

Dr. Rahman: It is relatively simple device. There are other higher tech approaches out there, but they are very expensive, are high maintenance, and don't always work. We take a simpler approach to this problem and it has a profound impact on these kids.

How do you keep up with their growth because obviously kids grow pretty rapidly?

Dr. Rahman: They come back periodically, about every six months to get a new back brace and we lengthen some of the links. With the 3D printing, we can do that pretty easily.

Is this something that a child could continue to use as an adult?

Dr. Rahman: We have had a few adults who started using the WREX as a child and they're still using it.

Is this developed for any other type of conditions or is it mostly for what Hannah has?

Dr. Rahman:  No, it is for a number of conditions, like muscular dystrophy and spinal muscular atrophy. Also, it's being used for adults with stroke and spinal cord injury at other facilities.

So, it has a multitude of uses?

Dr. Rahman: Yes.

Is there a certain age where kids should start this is?

Dr. Rahman: We think the earlier the better. That's why we have this ongoing project with babies. However, it is still a relatively new device. It remains to be seen what the best age is and when to do it.


Karen Bengston
Public Relations Manager
Nemours/Alfred I. duPont Hospital for Children
(302) 298-7319