Replacing knees, hips and other bones has become commonplace, but surgeons have to do a lot of bone cutting to attach the man-made parts, which come in standard sizes, to the body. The makers of rapid prototype systems say they feel they can change that by creating bone replacements built to fit each patient's body.
Researchers say bones can be scanned and modeled so the rapid prototype machines used in design and manufacturing can build parts that will fit into the body more easily, saving surgeons time and reducing trauma for the patients.
Many companies are now looking at ways to build custom parts that will go into bodies. "There are all kinds of initiatives going on. We're working with over a dozen medical companies that are analyzing the materials," says Kirby Quirk, sales manager at Stratasys Inc. of Eden Prairie, MN.
A key reason for interest is the emergence of rapid prototyping gear that creates parts with metals rather than plastics. While plastics are extremely strong, metal components are more commonly used for bone replacements.
Researchers hope metal replacements can mimic the success plastic components have had in some medical applications. Suppliers like 3D Systems Corp. of Valencia, CA, have made major inroads with plastic parts such as hearing aid bodies.
"The hearing aid industry has been turned on its head by rapid prototyping," says Todd Grimm, president of T. A. Grimm & Associates, Inc. of Edgewood, KY. Companies now routinely measure the person's ear and create a housing that fits perfectly in the ear using rapid prototyping machines, he explained.
But when the industry looks deeper into medical applications, a major difference is that hearing aids aren't as strictly regulated by the Food and Drug Administration as bone implants are. However, European companies are already building a few custom parts in this manner, so advances should come quickly, Quirk notes. Some suppliers say they could receive initial FDA certification early next year, he adds.
He said he feels that since titanium-based metals built from powders by rapid prototyping machines can be hardened to nearly the same properties as conventional metals, approval could come fairly quickly. "The FDA doesn't care about the manufacturing techniques, they care about the end part and the processes used to assure consistency," Quirk says.
Observers predict that unless the FDA balks at certification, the technique will probably see widespread acceptance, though it won't happen overnight. "This is very likely to happen in a broad sense, but there are a lot of barriers," Grimm says. Foremost among them is that busy doctors are often reluctant to take time to try new technologies, he adds. Another way rapid prototyping suppliers hope to get into metal-part medical applications is to make devices, such as scalpels, that aren't regulated by the FDA.