One full sized Iron Man costume. A set of portable wheelchair ramps. And a personalised phone case. From the frivolous to the functional and the just plain everyday, 3D printing is responsible for churning out all of the items on this eclectic shopping list. With a community of 3D printing enthusiasts sharing their digital models online and a few hundred pounds spare to buy your own 3D printer, you too could be producing any number of weird and wonderful trinkets. However, 3D printing just got serious. Recent years have seen this technology evolve to greater use in the medical field.
The noted tome Grey’s Anatomy depicts images of the human body in beautiful detail. However, reality is far messier and further complicated by variations from one individual to the next. So if you're ever in need of surgery, you'll be hoping your surgeon has racked up lots of experience on previous patients. But what if your surgeon could safely practice on your own unique anatomy beforehand? This is where 3D printing comes in.
Looking to the lungs, doctors in London and Amsterdam teamed up to apply 3D printing to treat a six-year-old child with a rare lung disease. The disease – primary alveolar proteinosis – causes excess proteins to accumulate on the inner surface of the lungs, hampering the body’s ability to absorb oxygen and remove carbon dioxide. To ease these symptoms the lungs need to be washed out, one at a time, using special endotracheal tubes that are carefully channeled into the lungs via its bronchi – the passageways that keep the lungs ventilated. While one tube ventilates one lung, another tube washes out the other – a tricky enough procedure in adults.
In small children this is made even harder by a lack of appropriately sized endotracheal tubes, resulting in an increased risk of tissue damage and potentially dangerous drops in oxygen levels.
Knowing the exact dimensions of the bronchi would be a major help in selecting the endotracheal tubes that best fit. Even better would be a map of precisely where the bronchi bend and narrow. The combined powers of 3D printing and computerised tomography (CT) – an imaging process also known as CAT scans – now make this possible. The team imaged the child’s airways using a CT scanner and the images fed into a piece of software that constructed them into a 3D model. The model was then printed out layer by layer in clear resin.
Using this personalised model of the child’s airways the doctors tested different sizes and types of endotracheal tubes, eventually identifying the combination that worked best, ruling out tubes that were too wide and too short. Having the specific contours of the airways to hand also meant they could plan the best way to position the tubes as they entered the airways.
Armed with this knowledge, the procedure was a success and a significant step forward from the previous year when the then five-year-old child underwent the same procedure – without the aid of 3D printing – and endured a serious drop in oxygen levels.
Medical uses for 3D printing now extend beyond trial runs of tricky procedures. Being both affordable and customisable, it has been used to print off teeth, prosthetic limbs, and even replacement skull parts. Novel uses continue to grow as new ‘inks’ are developed, from biocompatible metals to biodegradable chemicals. Research is already underway to take 3D printing to a molecular level. Someday you may find yourself picking up a blueprint and some chemical ink to print off your prescription drug at home. It’s a whole new world in 3D.