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About the size of an avocado, it is transparent but has coral-like structures of various colors running through it. Christophe points to an orange element that at first glance vaguely resembles walnut in shape. The structure that the surgeon and urologist at Bordeaux University Hospital are holding in his hands is a kidney from a 3D printer. It is intended to help surgeons like Bernhard better prepare for kidney operations on cancer patients.



In no other area does the 3-D process inspire people’s imaginations as much as in the world of medicine, where in the future healing will even be possible for ailments for which there were previously no or only insufficient treatment options. However, doctors like Bernhard can only dream that one-day organ donations will no longer be necessary because the new kidney or the new heart, including all the necessary blood vessels and organ structures, can simply be printed out. So far, medicine has had to make do with 3D products made from conventional materials such as plastic, metal, or ceramics.

The market for artificial teeth, hip joints, or knee prostheses from the 3D printer is developing particularly rapidly. This is also due to the demographic change in many societies: as the average age of the population rises, so does the number of people who struggle with diseases typical of old age, such as arthritis or cardiovascular problems, and who are therefore increasingly dependent on replacements that are as precisely tailored as possible.

The processes used to produce dental prostheses, knee joints, stents for trachea or skull plates from the 3D printer differ technically from one another, but the principle behind them is always the same: a three-dimensional model is broken down into thin layers on the computer and then special machines are printed out layer by layer until a real object has emerged from the virtual 3D model on the screen.

The new process is becoming increasingly popular, especially in the business of medical prostheses. This applies in particular to dentures, where the number of additively manufactured implants is increasing rapidly. The technology has already almost supplanted classic production in some countries, as the founder of the German 3D printing provider Eos, Hans Langer, stated more than a year ago. In the future, according to the entrepreneur’s vision, dentures will no longer be produced traditionally with a wax knife and impression tray, but with a mouse click and an intraoral scanner.

Additively manufactured artificial replacement parts have been used in surgery for years. This applies in particular to orthopedics, where more and more patients are opting for a knee, hip, or shoulder joint made by a 3D printer. This means that the bone is better covered and the replacement part can grow well,” says Christian Lüring, Director of the Orthopedic Clinic in Dortmund.

The clinic is Germany’s leader in the use of artificial knee joints from the 3D printer. In contrast to the standard procedure, in which the surgeon selects a joint prosthesis from the medical spare parts catalog and then adapts the bone to the respective model, with the new 3D implants the prosthesis is custom-made for each patient. First, CT images are taken and the images are then sent to the manufacturer. There, a computer calculates the ideal prosthesis, which is then printed out in 3D and sent to the clinic.

Annually Operations with a 3d printer

The 40-year-old and his team perform more than 350 such operations on the knee joint every year, and for every third operation, the patients now opt for a prosthesis from the printer. The fact that there are not, even more, is mainly due to the significantly higher costs: an artificial knee joint made of a cobalt-chromium alloy costs on average a good 1000 to 1400 euros – for the counterpart from the 3D printer, the one from the same material is manufactured, the manufacturers usually call for twice as much.

“The new products are therefore only likely to become established across the board when the prices for such joints from the 3D printer drop significantly,” says Lüring. Especially since some patients have been put off by the fact that there is no long-term experience with the 3D implants: whether the joints from the 3D printer, which have been used for about three years, last as long as the conventionally manufactured standard model, which has now been in use for 25 years, only time will tell.

Meanwhile, research is evolving rapidly. For example, scientists at the Fraunhofer Institute for Laser Technology in Aachen have developed a process that can be used to create branched artificial blood vessels. In the future, they should improve the blood supply for skin substitutes that are cultivated outside of the human body. In Berlin, on the other hand, a team from the Technical University is working on developing artificial heart valves from the 3D printer that can one day be populated with human tissue and implanted in the body.

But where are the limits in 3d printers?

“I reckon that one day there will also be artificial knee joints made of bone-like material from the 3D printer,” says Lüring. The doctor from Dortmund also considers artificial heart valves manufactured in this way to be conceivable.

There are already more question marks with artificial organs from the 3D printer: “It will be extremely difficult to produce them in such a way that they not only replicate the organ but actually also take over the function of the heart, liver or kidneys and permanently can be connected to the bloodstream,” he says.
Difficult, but not necessarily impossible. The revolution in the world of medicine has only just begun.