Doctors at the Xijing Hospital of the Fourth Military Medical University in Xi'an, Shaanxi province say they have used “4D printing” to reconstruct the breast of a cancer patient. The 3D printed breast implant will biodegrade over time—the fourth dimension—allowing human tissue to replace it.
3D printing in medicine is one of our most frequently covered topics. You’ll probably have noticed the articles about 3D printed skin, 3D printed ears, and everything in between. But something we write less often about is 4D printing in medicine.
There are good reasons for that though. For starters, this is 3Ders, not 4Ders. But more importantly, there’s no established definition of what “4D printing” really means, only that it’s an awful lot like 3D printing, but with some element of post-printing change or movement in the printed object. This accounts for the fourth dimension: time.
So when we heard that doctors in China had “4D printed” a breast for a cancer patient, we were interested—if a little skeptical about the terminology.
Here’s the scoop: doctors at Xijing Hospital of the Fourth Military Medical University in Xi’an say they have created a 3D printed implant for a cancer patient that will allow human tissue to grow inside it and eventually replace it altogether.
The patient, a 28-year-old going under the pseudonym “Zhang Xue,” had a 6 cm tumor on the affected breast, causing her to need a mastectomy after chemotherapy failed to remove the cancerous area.
But that wasn’t the end of the story for the patient. By using an MRI scanner to collect images of the breast prior to its removal, surgeons were reportedly able to make a 3D model of a breast implant.
Unlike silicone implants, which are designed to completely replace the organic breast and are not biodegradable, this kind of implant will degrade over time. Surgery to implant the 3D printed breast took place on August 8 last year, and the implant is expected to biodegrade over the course of a couple of years.
“It is sufficiently strong, and will degrade in designed period of time, which is in the patient's case one to two years,” said Zhang Juliang, an assistant professor in Xijing Hospital who participated in the surgery.
What’s exciting about the procedure is that the patient’s own fibrous tissue is reportedly growing into the implant, and will eventually replace it altogether.
They’re calling this “4D printing” because the 3D printed object, the breast implant, changes over time, eventually disappearing altogether. “Compared with three-dimensional printing, 4D printing adds time as another dimension,” clarified Ling Rui, a vascular surgery doctor at the hospital.
We think we can get on board with that usage of the terminology, but there are still a few question marks hanging over the story. For one, we don’t know exactly what the 3D printed implant was made of—only that it is some kind of biodegradable “filler”—nor do we know what kind of 3D printer was used. These seem like important details to be omitted from initial reports in Chinese media. Still, if the reports are true, what the doctors have achieved sure sounds impressive.
Ultimately, what’s most important is the health of Zhang Xue. And according to doctors, she’s doing just fine.
“In the ten months since the surgery, the implant has grown well, and the patient's veins and tissue have started to grow back,” Ling said, adding that the procedure should result in fewer side effects than other cancer treatments.