Three-dimensional precision opens new possibilities

It sounds like a virtually unsolvable problem: create an artificial structure that mimics a function that is a result of human evolution. One that is as firm and flexible as the biological tissue it is replacing, that remains stable the entire time it is in the body and doesn't wear out or disintegrate. And yet, it exists as the intervertebral disc prosthesis manufactured by B. Braun. It consists of a single material—titanium—noted for its biocompatibility, corrosion resistance and stability. With its precision shape and sophisticated lattice structure, this implant is one of the most effective prostheses made.

Its properties are made possible through additive manufacturing, commonly known as 3D printing. In this case, a thin layer of titanium powder onto a plate on the production line, then a laser melts it with micrometer precision at preprogrammed points to form a three-dimensional shape. Layer by layer, the object is created from AESCULAP® Structan®, which has exactly the structure and surface requirements that were determined in numerous medical and biomechanical tests.

More than just a box

Dr. Frank Kandziora knows exactly how additive manufacturing can affect the wellbeing of patients. The head of the Center for Spine Surgery and Neurotraumatology is considered one of the world’s leading experts, and he was one of the first surgeons to use a 3D-printed implant from B. Braun in 2020.

“It's a cage, if you like, just a small metal box,” said Dr. Kandziora. “But there's a tremendous amount of know-how packed into it.” As a result, he continued, the quality of the implant cannot be reduced to its individual parameters, rather it is dependent on a complex interaction of material, surface, structure, geometry and biomechanics—all properties that have a decisive impact on how the implant is manufactured. 

Another chance for the spine

The implant Dr. Kandziora used is the AESCULAP® TSPACE® 3D cage from B. Braun. It is used to stabilize the lumbar spine. This surgery is needed when one or more disks become so degenerated that they can no longer stabilize and cushion the spine. The spine then begins to slip, putting pressure on nerves and causing patients immense pain. “We try to eliminate this instability by using this kind of cage as a brace,” said Dr. Kandziora, explaining the procedure. How quickly and completely the implant heals with the adjacent vertebrae is crucial to the success of the procedure.

“The major advantage of 3D-printed implants is that they have a superior structure that allows the bones to adhere faster and better,” said Dr. Kandziora. “It’s plain to see.” This structure is made possible using additive manufacturing, since the laser allows almost any three-dimensional shape to be produced. In the center of the implant is a cavity, through which the bones can continue to grow. “The size of the holes, their configuration and the rigidity of the entire implant are important for giving the bones the tiny movements they need, and stimulating the healing process,” said Dr. Kandziora. The basic shape also is not left to chance, either. “The box design gives the bones a larger support area, which prevents cutting into the superior and inferior cartilaginous endplates.” This reduces the risk of the implant sinking into the vertebrae, which could compromise the function and stability of the spine. 

​Not only does the macrostructure play a role, the surface of the prothesis is also crucial. “Implants, mostly made from PEEK (polyether ether ketone) plastic, were used for years,” said Dr. Kandziora. “Their surface is too smooth; the bones don't heal properly.” In contrast, the 3D-printed implant has a porous surface, ideal for creating the conditions bone cell adherence needs. “Many patients don’t even need pain medication after two weeks. After three months, most have healed so well that they can go back to their normal life,” said Dr. Kandziora on the use of TSPACE® cage. 

Orthopedic products are just the beginning

The clinical success already achieved with 3D-printed implants is so impressive that B. Braun now has its Innovative Materials & Technologies R&D Team researching new additive manufacturing process facilities, which could fundamentally change how B. Braun develops, manufactures, and works with some of their products in this sector.

B. Braun's goal is to identify other products where advantages such as those in the 3D-printed intervertebral disk and hip socket implants can be found. “With additive manufacturing, we can create innovative products that could not be manufactured any other way, and offer our customers added value. It's a tremendous privilege to get to work with such a valuable technology,” said Patricia Graf, who has led the Innovative Materials & Technologies R&D Team at B. Braun since 2017. Customer requirements could be addressed even better, and unconventional solutions could be processed efficiently. An idea that Dr. Kandziora also finds fascinating: “The fantastic thing about this technology is that a standardized process can almost produce a one-of-a-kind product,” he said. “In the future, every patient could get their own custom implant.” B. Braun already manufactures implants in uncommon sizes for patients where a standard solution will not work due to their anatomical requirements.

Graf also sees serious potential in utilizing the advantages of additive manufacturing during the production of surgical instruments. “These instruments usually need to be held in the hand,” said Graf. The lighter and slimmer they are, the easier they are to handle and the better the visibility of the surgical site. 

New vertical integration

Additive manufacturing doesn't just promise major advantages for products—it is also changing basic working operations in the company. During the production of 3D-printed implants, B. Braun controls the entire process chain. This is a vertical integration that not only makes production more resistant to external factors but also makes it possible to efficiently integrate it into company processes. Before complex medical devices such as implants can be 3D-printed, they must go through a number of stages: from development to design, through lengthy biomechanical tests and clinical trials. And even after the actual printing process, they need to be cleaned and finished in a time-consuming process. “Because we have all of these capabilities in house, the process offers new opportunities,” said Graf. Additive manufacturing, of course, is not limited to just medical products. “We are also using the technology to create fixtures for production. And we're looking into which replacement parts we might be able to manufacture for our machines in the future,” said Graf. 

Sustainability through innovation

Additive manufacturing also has the potential of making production significantly more sustainable. Not only can the product be manufactured in one piece on site, which eliminates the need to transport intermediate products, additive manufacturing is also much more efficient in terms of materials. Products that had been machined from a solid material can be 3D-printed in a way that uses hardly any more material than what the end product requires. The leftover titanium powder is also sifted and reused for the next batch.

However, the most important way in which additive manufacturing is shaping the company concerns another area. “The development of new products and implementing them in a production line takes teamwork,” said Graf. “Additive manufacturing is a technology that really gets everyone excited,” she added. “I think I’m very lucky to get to work with people with such dedication and excitement who want to get the most out of it.”