To Repair a Shattered Face, Print a New One

3D printing has been around long enough now that it takes a lot for new applications to impress. Then you hear about something like these plans to use 3D printing to reconstruct someone’s face after a motorcycle accident, and it reminds you why the technology seemed so revolutionary to begin with. There’s little more unique than a person’s face, and 3D printing allows for the kind of tailor-made solution you’d never get with off-the-shelf parts.

Of course, 3D-printed medical implants aren’t a totally new idea. Last year, a woman received the first 3D-printed jaw, and we’ve also seen 3D-printed replacement skulls and bionic ears, not to mention bio-printed blood vessels and (almost) functioning human organs. But this new operation combines several innovative methods to push a new level in sophistication when it comes to additive manufacturing and the human body. Although the surgery isn’t scheduled until early next year, the work is already on display at London’s Science Museum, as part of their “3D: printing the future” exhibition.

I spoke to the Adrian Sugar, the maxillofacial surgeon leading the work at Morriston Hospital in Swansea, Wales, to find out just how you go about fixing a face with 3D printing.

It’s clearly quite an extreme case. It started over a year ago, when a man was brought into the hospital after a road accident that left him with severe injuries across his body. A team of surgeons worked on the patient right there in the early hours, but had to restrict their attention to the most urgent treatments; reconstructive surgery wasn’t a priority at that point. “He was in a fairly bad way after this accident, and although his facial injuries were very nasty indeed, we were a little limited in what we could do in treating those at that time,” said Sugar.

Now that the patient has had some chance to recover from the incident, Sugar’s team has planned a reconstructive procedure using pioneering new methods. The main aim is to restore the symmetry of his face, which suffered a lot of damage. “His injuries consisted originally of fractures of all of the upper and middle part of the face,” said Sugar. “So that’s his forehead, his nose, both of his cheekbones, and his upper jaw, were all fractured and were all affected by this accident.” A lot of that has since been fixed, and the right side of the patient’s face is in pretty good shape. His left cheekbone is still out of place, however, as are the bones around his left eye socket, which is affecting his vision.

To restore the left side of the patient’s face, Sugar’s team came up with a way to “mirror” his good right side onto it. First, they imaged his face and head using a CT scan, which scanned the area in “slices” down to an accuracy of 0.2mm. “From that we can produce a 3D image, a virtual image,” the surgeon explained. “In other words, it’s a model of the face and the head but it’s on a computer screen.”

The researchers could then manipulate this virtual face to get the desired result. They flipped the right side of the face onto the left side of the model, to make for a symmetrical result that best resembled the man’s features before the accident. They could also effectively practice the surgery on the computer model, to see which changes were necessary to fix the damaged features into the desired position.

They decided they’d need to cut the cheekbone in three pieces and move them, but finding the perfect placement was tricky. Having a virtual model to play with came in really handy at that point. “If you work with a physical model, once you cut something and move it, you’ve destroyed the model,” said Sugar. “Whereas if you work on a computer screen, you cut it and you move it, and if you don’t like it you start again. And you can do it many many different times and many many different movements until you’re satisfied with the movement.”

Up to now, they've got as far as performing the virtual surgery to their satisfaction, but actually physically cutting and moving bone is understandably rather more delicate; you don’t want to make a mistake in the middle of someone’s face.

That’s where the 3D printing element comes in. To help carry over their virtual work into the physical operating theatre, the team have made physical guides custom-designed to fit over the patient’s fractured bones and show exactly where to cut and move them. The guides were designed on screen using a haptic tool—Sugar described it as “a bit like a 3D mouse but with bio-feedback”—and 3D printed in a cobalt-chrome metal by specialist additive manufacturing company Renishaw.

After the team repositions the bones, they’ll need to fix them in place with titanium plates and screws. For an accurate result, they have also been 3D printed to fit, this time by Belgian firm LayerWise. These implants will stay with the patient for life, if all goes to plan.

Sugar has been working with 3D printing for around seven years, as part of the Centre for Applied Reconstructive Technologies in Surgery (CARTIS) initiative, which is a partnership between his unit at Morriston Hospital and the National Centre for Product Design and Development Research at Cardiff Metropolitan University. But he explained that several factors made this latest project particularly cutting-edge.

“What we’ve done that’s different in this case is we’ve actually found a way to make the guides first of all in metal, which is of course much better for sterilising and much stronger,” said Sugar. “And also to make the actual implants without having to take the guide off. In other words, we can do the repositioning and we can do the reconstruction and then take the guides a way.”

Essentially, they built slots into the guide that the plates and screws can be inserted through. That way, the guide only has to be removed when everything’s fixed in place, and nothing’s left to guesswork. It sounds simple when you put it like that, but it's just the sort of delicate one-off design that would be near impossible without 3D printing.

Of course, the result won’t be perfect; you’re never going to put someone’s face back together as if it were a jigsaw puzzle, and although the desired result of the operation would be to restore the patient to exactly how he looked before the operation, Sugar admits that’s unlikely. “In reality, I’ve told him that if we achieve 70 percent of that, that would be, in my opinion, a success,” he said.