How 3D printing is being used in medicine

Innovative uses of additive manufacturing are dramatically altering the way doctors interact with the human body. This article is showcasing these new developments.

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11 Nov, 2019

The first 3D printed polymer implant to receive FDA approval.

The first 3D printed polymer implant to receive FDA approval.

Sophisticated techniques for scanning and mapping the human body and its complex chemical and electrical activities now allow researchers and doctors to know more than ever before about how the body functions and also how to intervene when something goes wrong. Doctors and ordinary folks are now becoming engineers when they combine this knowledge with additive manufacturing and 3D printing to create an astonishing array of solutions for fixing whatever ails us. Let’s look at some of these amazing adaptations.

Image cred: Autodesk

Bones, Joints And The Skeleton 

There are more than 230 bones in the body and 360 joints. Through accident, disease or the ravages of time, these joints wear out and cause chronic pain and loss of movement. As a result, joint replacement surgery is one of the most common procedures in the world but it’s been largely available only in developed countries. Now with compact 3D printers combined with optical scanning, it’s possible to create new joints and sockets for hips, elbows, shoulders and feet which are fast, affordable, custom-made and ready on the spot rather than being shipped from abroad. The ones shown here are titanium, which is strong and biocompatible. In addition, the coarse surface texture – made easier with 3D metal printing – are ideal for creating porous surfaces into which new bone can grow over time.

Image Credit: Trend Hunter

This is not a bionic man but is a picture of a new sternum (breastplate) and ribs created from titanium to replace those lost to cancer – the first such large-scale procedure making use of additive manufacturing.

I’ve written before about partial skull replacements, but recently a surgeon in the Netherlands used 3D printing to create the entire cranial skull in two pieces, a perfect match for the patient’s facial and neck bones.

Prosthetics

There are millions of people around the world who must do without a limb or two. History records the use of wooden peg legs and arms as far back as 400 BC, but no doubt the practice is even older. Articulated wooden limbs to replace those lost in war started to become more common at the end of the Civil War conflict in the United States, but they were still heavy, clumsy affairs and each had to be measured and fitted by a specialist craftsman – an expensive proposition for many.

Image Credit: Melissa Ng

Now accessible 3D printers can be used to make new limbs in lightweight plastic or even carbon fiber which are perfectly matched to suit their new owners, and which even have quite a bit of design flair. Impaired athletes are also using springy artificial legs to compete at the highest levels of track and field sports.

This articulated hand was created by a carpenter who lost his fingers in a woodworking accident. Not only did he design it himself and create activating motors, but he put the pattern onto Thingiverse to make it available to anyone else similarly in need. Both resourceful and benevolent.

Casts And Medical Aids

Courtesy: Jake Evill

Unfortunately we are prone to fracture or crack our bones sometimes. What that happens, it’s traditional to use a plaster cast to hold the affected bone in place while it heals. But plaster casts are hot, heavy and itchy, not allowing the skin to breathe. This 3D printed solution was made by creating a scan of the patient’s arm along with a detailed X-ray. Not only is this cast lighter and stronger than plaster, but it can be tailored to provide added strength and support precisely at the point of the break where it is needed, while reducing weight and providing a degree of flexibility elsewhere.

Courtesy: Exo-L

Better than healing an injured limb is to prevent injury in the first place.That was the idea for the creation of an external joint aid, called the Exo-L. Developed by Delft University of Technology and the Erasmus Medical Centre in the Netherlands, the device is custom 3D printed to match the wearer. It fits comfortably and is designed to prevent the ligament from twisting during sporting activities.

Orthodontics
Image cred: Formlabs

Tooth decay and tooth loss is as old as man himself. We dread to consider what early dentistry must have been like. Dentures and artificial teeth are now quite commonplace, and it’s even possible to 3D print teeth in high-tech materials like stainless steel or titanium. But here’s another future option. This tooth is made from ordinary dental resin that’s been impregnated with ammonium salts. The result is that it kills most disease-causing bacteria on contact. Even with dentures there is still the danger of gum and nerve disease but this innovation might make that a thing of the past, and it’s almost as strong as the real thing.

In the next part, we’ll look at other medical miracles taking place involving tissue, organs and drug therapies.

Stem Cells

Human cells of different types can now be routinely cultured from samples taken from a donor, but those cells must be of the same type – muscle cells are always going to be muscle cells, and brain cells will always be brain cells. Human embryonic stem cells, however, are protean in this regard. They can be developed into any kind of cell, once they have received the programming trigger from the appropriate enzyme.

It is for this reason that stem cell research is so promising in many areas of medicine, offering the hope of creating new tissues and organs custom made for a needy recipient, thereby obviating the need for organ donors. Stem cells are also ideal for testing potential drug reactions without exposing a live subject to risky side effects.

A huge step forward has now been made in the use of a modified 3D printer to print stem cells in a cultured medium. This would theoretically allow any type of human tissue to be printed onto a substrate to create replacement organs at will. Not there yet, but getting closer.

Image Credit: psfk

Skin

Skin grafts have previously been available through the process of taking samples from the patient’s own body and using those patches for the damaged area. Now it is possible to replicate a person’s skin cells and print those cells in unlimited amounts without needing to take a graft.

Furthermore, at the Wake Forest Clinic, doctors are using 3D printed cells applied directly to burn victims, the fastest such treatment so far developed. And with the use of sophisticated laser scanners and optical cameras, it may also be possible to print sheets of skin which are copies of the original – complete with correct skin tone, freckles and wrinkles.

Image Credit: Victoria

Prosthetics

There have been silicone rubber anatomical prosthetic ears and noses for quite some time, but they have suffered from a lack of realism as well as being insecure to wear. But now it’s possible to make a 3D printed lightweight plastic scaffold that is tailored to suit the precise contours of the wearer’s bone structure. This scaffold then becomes the foundation for the later application of printed skin tissue, to make a more complete prosthesis.

It’s important to acknowledge, for this application and so many others in the medical field, how much is owed to advancements in scanning and computerized topography. Calculating the complex three-dimensional shapes and creating an accurate digital file is every bit as important as the technology which delivers micro-fine droplets of printing substrate.

Image Credit: Gizmag

3D scanning and printing technology were essential to a successful facial transplant for a man whose own features were destroyed while fighting a fire. In this case, after comparing the bone and facial structure of the patient with that of the donor, a cutting guide was fabricated to assist in matching both of them for a precise fitting. This is the most comprehensive such procedure ever done.

Image Credit: Venturebeat 

Blood Vessels

Building organ tissues in a culture is now a relatively straightforward procedure. But a fully-functioning organ is more than just tissue. To thrive, it requires a network of very fine blood vessels to provide nutrients and flush away toxins. Until now, such a network was impossible to reproduce in a laboratory.

Scientists from Harvard, MIT, Stanford and the University of Sydney created a scaffolding of microfibers, which was then coated in specialized cells with a nutrient bath. Once the cell colony was established, the fiber framework was carefully removed, leaving behind functional, hollow capillaries that then grew naturally. This has yet to be implanted within a living organ, but again the process shows what will be possible in the near future.

Image Credit: Trendhunter

Exoskeletons

There are many people paralyzed every year due to damage of the spinal cord. In too many cases they may never use their limbs again and we still cannot re-attach a severed cord. But with 3D printing technology, we can make a customized exoskeleton which interfaces with the owner’s commands to allow independent freedom of movement.

Amanda Boxtel was paralyzed in a skiing accident and hasn’t walked in more than 20 years. Doctors combined their knowledge of her anatomy with a customized exoskeleton that made use of 3D printing to perfectly adapt the suit to her existing frame. Without such an exact fit, the exoskeleton would chafe against her skin in places where she has lost all feeling, causing abrasion and infection.

This exoskeleton has servomotors which are then activated by thought-controlled sensors, allowing her to move at will.

If you have questions, or feedback, feel free to leave them below in the comments.

This article has been published earlier on Star Rapid's blog.


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11 Nov, 2019

I am a British China based entrepreneur in the field of 3d printing, rapid prototyping and low-volume custom part manufacturing including CNC machining and plastic injection molding. I am also a keen amateur economist and I read and write extensively on political economy, world history, and globa... learn more

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