Surgical outcomes are increasingly being scrutinized by groups like the National Health Service (NHS) and World Health Organization (WHO), who audit outcomes and publish their findings. With increased scrutiny comes increased pressure to improve patient outcomes. The goal of any surgery is to limit the amount of incurred injury to the patient. Implant surgeries, whether they be knee or hip replacement, are no exception.
Most implant surgeries include using cutting guides that allow the surgeon to make accurate, minimal cuts during a procedure. Conventionally, surgeons have a kit with various sized incision guides for correct replacement size, and it’s a tedious process requiring a skilled surgeon to properly place the implant or part—a priority for optimal functionality and healing. This one size fits all approach is transitioning via additive manufacturing innovations.
Surgical procedures often call for taking a CT scan of the patient’s anatomy prior to surgery, establishing an exact digital twin of their body composition. This digital twin of the patient’s anatomy assists in creating a disposable surgical guide that is matched to the patient’s exact make-up for making optimal, minimal incisions and placement of the implant. These guides can assist the surgeon by taking ambiguity out of the surgical process.
Siemens currently provides Image-to-Implant software, which assists in automatic filtering and remediation of an image scan before producing the implant, to further refine the surgical planning process. All products from Siemens Digital Industries Software are part of the Xcelerator portfolio where cutting-edge software products are turned into problem-solving solutions.
Traditional methods for manufacturing surgical implants require casting and machining with multiple parts. Each cast requires a mold, with a single mold ranging in cost from $1 million to $5 million. Thousands of parts are produced from that one mold, thereby driving down the cost of each individual part and generating the proper return on investment.
Medical implants are commonly cast or machined because obtaining regulatory approval for additively manufactured implants to be used permanently or semi-permanently inside the human body is a lengthy and expensive process. However, these traditional manufacturing methods are not applicable to creating implants with special lattice structures. These structures are often added to implants to encourage bone growth to integrate within the implant.
Besides software improvements, new developments in materials are furthering the advancement of additive manufacturing in medical applications. Digital materials involve taking a known physical material, like titanium, and using printed structures to alter the behavioral characteristics of that material. The part is still produced from pure titanium. However, it behaves in a manner not typical of a pure metal. For example, in the future the internal portion of a knee implant might be printed with a lattice structure that includes a spring-back coefficient, allowing the knee joint to cushion the junction of the implant and surrounding bone structure.
Though printed implants are not yet widespread, we’re seeing groundbreaking technologies and research evolving from additive manufacturing innovations. Even standard practices of using pins to hold-in-place a broken wrist or ankle are benefiting from additive manufacturing for custom fitting and improved healing time and quality. However, there’s a vetting process for any new discovery—which is necessary but takes time. Once the hurdles of testing and establishing certification are crossed, we will eventually witness the fruition of this experimentation and investment.
Over one million knee and hip replacements are performed annually in the United States. Cosmetic surgery continues a decades-old trend of increasing additive manufacturing adoption. There could even be a day when body parts or facial features are printed with biological materials.
The explosion of additive manufacturing adoption is evoking much hype about its technological possibilities, especially in the health care industry. However, the realities of printing a part for the human body that is good for 10,000 cycles or a lifetime is an intimidating task. The medical industry is moving past a period of disillusionment with revised expectations of what is possible with 3D printing in the near-term versus some of the original unrealistic expectations. We’re witnessing a gradual resurgent interest in using additive manufacturing for medical purposes, but full-scale adoption will take time.
Every surgery has unique requirements, specific to the patient. Therefore, even though custom surgical guides are being additively manufactured, there is still considerable intervention required from the surgeon. Surgery will always be a customized process, unique to each patient and situation, operating on an individualized basis.
Additive manufacturing allows medical professionals to make custom products with a lot size of one for a small premium, on top of the cost for a mass-produced part. In many cases, the quality and speed of patient recovery has easily justified the small premium paid for custom implants and surgical guides. This small increase in a personalized additive approach could circumvent any money saved with mass production.
With additive manufacturing and custom medical products, it isn’t just about making better products, but driving towards better patient outcomes. Medical patients of all types can be the beneficiaries of customization, enabled by additive manufacturing, leading to less cost and positive patient outcomes. Jim Thompson is director of strategy for medical device and pharmaceutical industries at Siemens Digital Industries Software.
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