Additive manufacturing (AM) in medicine continues to grow each year. It is a remarkable enabler, but the industry is fraught with barriers to adoption, slow for the sake of patient safety. Even so, AM has seen significant acceptance, with tremendous growth on the horizon.
AM shines for making one-of-a-kind parts and products with complex, organic shapes. This mimics nature’s way of making every human body part unique. Medical device producers discovered this years ago, applying the technology to the production of in-the-ear hearing aids, most of which are customized. Today, the shells for these hearing aid products are made using AM. The hearing instrument industry was the first to adopt AM across most major manufacturers, including Phonak, ReSound, Singia (formerly Siemens), Starkey, and Widex. This shows how AM can become a go-to production method when the application is a perfect fit for the technology.
AM for medical implants is also important. They require complex textures, called trabecular surfaces, to integrate with surrounding tissue. AM is the most capable method for these structures in infinitely variable patterns. Stryker has used AM to produce more than 300,000 orthopedic devices for patients, many with trabecular surfaces.
Implant production using AM is already a maturing and expanding industry, but mostly for standard products and sizes. Examples: acetabular hip cups, spinal implants, and knee replacements. Custom implants are used, but are more expensive. Each implant must be modeled from scan data, built and checked. We believe custom implants will become more common in the future.
The Central University of Technology’s Centre for Rapid Prototyping and Manufacturing (CRPM) in South Africa has used titanium facial implants to successfully treat cancer patients for years. Recently, CRPM designed cages into the implant to hold proteins that stimulate jawbone ingrowth. After treatment and bone growth, the patient can receive dental implants.
Medical products must be cleared by governing bodies such as the U.S. Food and Drug Administration and the American Medical Association. In July 2019, the American College of Radiology led the industry in taking a tremendous step toward AM adoption. Category III Current Procedural Terminology (CPT) codes were enacted, which is the first step in patients being reimbursed for treatments involving models made by AM. Two codes were approved for anatomic models and two for surgical cutting guides. Without these codes, receiving reimbursement for these expenses can be very difficult.
To push standardization initiatives, more AM medical case data need publishing, showing that AM-based treatments are safe and effective. Fortunately, the number of AM-related articles published in peer-reviewed medical journals more than doubled from 2014 to 2018.
Influential groups are being formed to help advance the adoption of AM in the medical industry. One such group, the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing, now has 500 members and is growing. This is a strong sign that support of medical AM adoption is high.
In-house AM services at hospitals are also spreading and developing. At the end of 2019, more than 160 hospitals in the U.S., alone, had a central 3D printing facility of some type.
Hospitals without on-site AM capabilities can find support from groups such as South Africa’s CRPM. According to Professor Deon de Beer and Dr. Gerrie Booysen, surgery time—including ICU access, high-care facilities, and dedicated medical staff time—is cut in half when AM is used. Patient recovery is also faster and outcomes are more successful.
Today, what we see of AM in the medical field is the tip of the iceberg. Other topics such as regenerative medicine, 3D bioprinting, stem-cell research, 3D-printed drugs, and custom medical devices point toward a future where AM could benefit every human being’s quality of life.