Three-dimensional printers have had a major impact on the health industry as one of the most innovative technologies of recent times. These devices can create everything from a personalized prosthesis to living organs. Linda Gross, a medical writer and consultant in medical technology at the Emergency Care Research Institute (ECRI), analyzes the expectations that surround the new technology.
What uses do 3D printers have in the health industry?
In fact they have many applications, such as the creation of dental implants, personalized prostheses, knee implants and guides for craneomaxilofacial surgery. The University of Michigan has even printed small frames to support the tracheas of children born with underdeveloped respiratory tracts.
For the moment they are being used to create surgical guides for complex anatomy so that professionals can practice before the actual procedure. Generally, a CT scan is taken of the patient and then design software is used to give printing instructions to the printer.
How do the organs printed by these machines work?
Bio-printing is still in a pre-clinical phase and cannot be used with humans. Academic medical centers such as Princeton University, for example, have printed prototypes of ears cultivated from cow tissue but not to implant in a human being. Companies such as Organovo print livers and kidneys on which to test drugs using a “proprietary method” of cell and organ tissue cultivation. At the Wake Forest regenerative medicine institute, which is working with the United States Department of Defense, scientists are working on printing skin cells using the patient’s own cells.
What materials do these printers use?
It depends on their use: the companies that print knee and hip implants use titanium like traditional implants but the trachea frames I mentioned above use a bio-absorbable material known as polyprolactone (PCL), which is also used for sutures and ensures safe absorption. In fact, Wake Forest is carrying out in vitro experiments to determine the compatibility of different biomaterials with human cells.
In addition, many academic centers print prototypes of organs over a model, “planting” live cells so that they can form the shape of a real organ like a kidney. Some even use cells from umbilical cords or neonatal foreskins as “bio-inks” but these are not viable organs. We have years of research and development ahead of us before we’ll be able to print organs that can be implanted into human beings.
Are 3D printed implants and prostheses permanent or do they need to be replaced after a certain amount of time?
We don’t yet have any long term information about how well they last over time. I suppose that it would vary depending on the material, the printing method and where and how they are used. In any case, we must differentiate between prostheses (artificial body parts) and surgical implants (such as a knee or hip).
The prosthetic arms for children made by the volunteers at Enable, for example, were made with cheap materials because they knew that at some point as the children grow up they would be replaced by others to fit their size. With regard to the implants, they must be made from the same material as the traditional ones, but, again, time will tell how long they last.
Is there any risk to using these implants or prostheses?
There aren’t so many concerns about the prostheses as the implants. We still don’t have long term information about the “support load” of these implants, i.e.: their capacity to hold up the body in the case of hips and knees. Even in cases where the same material was used as traditional implants, the Food and Drug Administration (FDA) has questioned whether the three-dimensional printing process – via layers – has structural problems.
How long will it be before hospitals start using these printers independently?
We expect hospitals to invest in the technology, which is why the ECRI placed it in its Top Ten Technology Watch List. There are also companies that offer the printing service to hospitals; the greatest interest is in the surgical guides.
Is FDA authorization required to use them?
The FDA is monitoring this field as it emerges. Knee and hip implants, for example, have been approved by the FDA, as have the splints created by the University of Michigan.
What progress is expected in 3D printers?
Expectations are related to hospitals’ interest, both in terms of printing surgical guides as well as the development of personalized splints, stents and bone implants. It is also expected that research will continue into bio-printing, especially for vascular systems that could be incorporated into organs.
