3D printing and customised medical implants
3D printing is making major inroads into customising medical implants for individuals. It allows implant manufacturers and sometimes even hospitals to create complex geometries and patient specific solutions that saves the surgeon time and improves a patient’s outcome.
Largely used for orthopedic surgery, 3D printing is starting to break into other areas such as heart surgery and even replacement retinas in eyes. With research into bio printing there is even the chance that the future could bring a 3D printed heart. What was once science fiction is rapidly becoming science fact.
Just like industrial 3D printing, the process starts with digital data; in this case a computerised tomography (CT) scan. This is an imaging technique that uses x-ray measurements taken from many different angles to produce an image of the body. It is hailed as a way to see inside the body without surgery. The surgical team then use this information to plan and produce custom designed implants using 3D printing, often, but not exclusively, using titanium or stainless steel.
Better patient outcomes
At the moment most applications involve musclo skeletal injuries. The human body has 206 bones all of which support our body or protect vital organs, so when they are damaged this can severely affect a patient’s health and quality of life.
Using traditional methods creating an implant for a patient requires multiple medical appointments. At a time when a damaged bone could be causing the patient pain, reduce their mobility and affect their lifestyle, this long wait for an implant can be incredibly uncomfortable.
It also means that the implant is not ideal as it’s not tailored to their body. For the skull it could even mean that the patient is fitted with a mesh implant, which can be weak and lack precision.
This places the surgeon in a difficult position since they often need to not only operate on the patient but spend time adapting and reshaping the implant to make it fit better.
Fortunately, using digital imaging technology to produce customised 3D printed implants is making this process far faster for the surgeon and the result better and more comfortable for the patient. It also means that hospitals can reduce their inventory of expensive implants on site.
While additive manufacturing is still very much at the forefront of current medical technology and is not widely available, it is progressing rapidly.
Common examples of 3D printed implants include for the spine, shoulder joints, hip implants and for facial surgery and dental implants.
The skull and facial implants are good examples that require highly customised solutions. In the Netherlands for example, doctors have replaced the whole top of a 22-year-old woman’s skull with a 3D printed implant instead of a traditional option. In studies doctors found that 3D-printed skull implants were cosmetically superior, and patients often had better brain functions as a result.
New applications and materials
While titanium and stainless steel are favourite materials for orthopedic implants there is also progress in using high performance plastics such as PEEK. PEEK expands opportunities for the technology to move off the shop floors of medical device manufacturers and into labs at hospitals and clinics worldwide.
This opens up the possibility that a patient could be scanned, an implant designed and discussed in a virtual 3D environment, produced on site and then surgically implanted; all in the space of a couple of days. And because its design is based on the patient’s individual needs the surgery itself will take less time.
Meanwhile research is continuing to extend how far such customisation of implants can go.
Recently, we have seen examples of implants for parts originally made from organic tissue. A good example is a heart valve prosthesis made from silicone AM. Created by a team of researchers from ETH Zurich, these artificial 3D printed heart valves make it possible to replace valves in an aging population. Early results are promising, although such a solution is probably still a decade away.
Beyond this 3D printing technology offers new ways of working with other implant materials. This includes research in Australia for 3D printing stents using nitinol. This is a metal alloy of nickel and titanium that will resume its intended shape after deformation. While surgeons are already using this material for arterial stents, 3D printing will enable more sizes and configurations to better suit patients’ needs.
Clearly the idea of tailoring implants to a patient using 3D printing opens up numerous opportunities for more personalised healthcare. While many of these advances could be a few years off yet, the possibilities are almost limitless. Other examples of research include the production of artificial retinas for eye surgery and the potential of printing skin grafts or even a new heart.
While the latter two examples may not be available in the near future, it does open up a glimpse of what is possible using this amazing technology. Even more than other industries, it appears that the only limitations of 3D printing in medicine is our imagination.