3D-Printed Spine Implant Fosters Bone Growth

Novel 3D-printed titanium spinal device corrects spinal problems.

by Lina Zeldovich
February 15, 2019

In January, surgeons implanted a novel 3D-printed titanium spinal device into a patient to correct spinal problems. Osseus Fusion Systems designed and 3D-printed the implant, called Aries-L Interbody Fusion Device, to mimic the natural architecture of bone matrix to provide better outcomes for people who suffer from spinal disorders.

“This design facilitates the bones to fuse together faster,” said Samuel Joseph, Jr., a surgeon who pioneered the use of the Aries-L with his colleague Andrew Moulton.

Spinal fusions are surgical procedures used to correct a number of spinal problems, including herniated disks, deformities, and broken or unstable vertebra. According to medical data sites, surgeons perform close to half a million spinal fusions in the U.S. each year. Interbody fusions constitute more than 70 percent, or 352,000, of them.

During interbody fusions, doctors place interbody devices—clips, screws, spacers, brackets, and other hardware—between the vertebrae, fusing them into one segment.

To prompt the fusing process, surgeons pack natural or synthetic bone graft material into and around the interbody device, said Chase Tipping, Osseus’s product development engineer. This serves as a scaffold for bone to grow between the two vertebrae and eventually fuse them into one continuous vertebra, which mimics the natural process the body uses to heal broken bones.

In order to foster an efficient fusing process, an interbody device must encourage bone cells “settling” on and around it. A variety of interbodies are available, but their fusing potentials differ. Traditional interbodies, typically manufactured from plastic, are nonporous and not easy for a cell to attach, which means they do not offer bone cells an easy opportunity to adhere and grow. Some devices use a titanium coating. The coating allows cells to attach to it, but in some cases flakes off, which is not a desirable surgical outcome, Tipping said.

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The creators of Aries devices, Eric Hansen and Robert Pace, founded Osseus in 2012 to develop next generation products for spine injuries that would offer better performance than the existing systems.

“Over the last five years, we have worked to fill our product portfolio with novel solutions for the most common spinal fixation and fusion procedures,” Tipping said. “When the time came to develop a line of lumbar interbodies, the major questions were what material, manufacturing technique, and post processing methods would result in an interbody with the most clinical benefits and fewest drawbacks.”

One such goal was to maximize fusion. Aries interbodies feature a surface topography that is ideal for bone cell adhesion and proliferation, Tipping explained. The interbodies are constructed of a three-dimensional, interconnected lattice network that looks like a bone matrix. The structure encourages the bone cells to grow onto and into the device, creating a more robust fusion than traditional interbody implants.

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Osseus prints Aries interbodies on an FDA-validated selective laser melting (SLM) 3D printer by sintering titanium particles into a solid shape. It uses an approach called powder bed fusion, in which a 30 micron thin layer of titanium powder is melted onto a previous layer by a laser beam, to custom shape the device. “It’s called powder bed fusion because it lays down a very thin layer of powder and prints in a series of layers, with the laser beam melting layer upon layer,” Tipping said.  

Already approved by the FDA, the Aries-L won thumbs-up from the two surgeons who used it. “What really separates this new 3D printed cage from the older cages that were made out of plastic is that the old material itself wasn’t biologically active,” Joseph said.

With the Aries interbody, the bone cells are prompted mechanically by the familiar environment of the Aries device that resembles bone matrix, so they colonize it.

“This device has got a similar architecture to the bones so the bone cells recognize it as a scaffold to grow through,” he said.

The device can be used to fix spine instabilities, fractures, and degenerative disk diseases, and to correct scoliosis in some adult cases, he said. The next step would be to build personalized devices based on the patients’ specific anatomy via information from their CT Scans, X-Rays, and MRIs.

“This probably will start happening in the next few years,” Joseph said.

Lina Zeldovich is an independent writer.

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