U.Va. technology strengthens patients’ backbones
CHARLOTTESVILLE — It may not turn you into a cyborg or the Six Million Dollar Man, but it could help you walk straighter and ease skeletal back pain.
University of Virginia physicians have begun using a new, 3-D-printed, titanium back spacer designed to fit individual patients suffering from spinal deformities, whether from natural causes or traumas.
The spacer is designed to realign the spine to a more normal position and allow bone to grow through it to create a natural fusion in the spine.
Carlsmed, Inc., which creates the device, known as the aprevo implant, announced the first successful use of the implant in February during a surgery at the University of California San Francisco Medical Center.
U.Va. physicians are also early adapters of the device and were involved in its research and creation.
“It’s a spacer, and it’s currently approved for spine deformity cases, which are basically misalignments of the spine,” said Dr. Justin Smith, a professor of neurosurgery at U.Va. Medical School and director of U.Va. Medical Center’s spine division.
Smith said surgeries to correct misalignments often require cleaning out the remnants of spinal discs, nature’s spacing devices in the spine. Titanium rods, screws and either plastic or titanium spacers are used to shore up the spine and to realign it.
The idea is to put the spine right, add spacers to keep it straight and to have the body grow bone over the hardware to create a strong support where the disc once was.
“We’re often putting rods and screws in to reconstruct the spine with the goal of getting the bones that the rods and screws span to knit together solid as one, or to fuse,” Smith said. “The problem is that the rods and screws we put in are metal, and metal is imperfect. If the bones don’t knit together solid across those (devices), then the metal has to carry the body’s stress indefinitely. The metal can then fatigue, fracture and fail or the screws can pull out or rods can crack.”
An estimated six million adults have mild to severe spinal deformity, and 1.6 million seek treatment for the condition, either surgery or other treatment, each year.
Prior to aprevo, most spacers were off-the-shelf, devices made from surgical plastics and metals in particular sizes. While those implants have different heights to fit different length spines, they’re basically pre-formed blocks.
Aprevo is different, said Smith, who worked with Carlsmed to develop the device.
“They make it fit the exact shape of the surface of the bones above and below it so when it goes in, it hugs the bone above and below and has the maximum amount of contact,” he said. “It gives the best chances of healing and creating a solid fusion over time.”
Smith said CT scans and standing X-rays of a patient are sent to Carlsmed, a San Diego-based medical technology company. The company uses the scan and X-ray images to create a 3-D model and designs the implant based on the model.
The modeling is accurate down to the bumps and texture of the surrounding bone.
“The company plans out how the alignment of the spine should be and then designs the spacers to go between the bones to help maximize the correction of the spine,” Smith said. “Sometimes the implant will be a wedge shape instead of a block to help maximize the correction of the spine.”
The company then uses 3-D printers to make the patient-specific designed implant out of titanium.
“They’re often unusually shaped. The surfaces are often irregular and rough and mimic the bony surfaces,” Smith said. “Then the company sends the design to the 3-D printer where they can print any shape they want.”
In 2019, Carlsmed completed a merger with a Seattle-based spine imaging system company to create the medical industry’s first personalized surgical workflow platform.
“Imaging for severe spinal deformities is primarily used for diagnostic purposes only,” Mike Cordonnier, cofounder and CEO of Carlsmed said in the 2019 announcement. “This enables creation of devices and surgical plans in a build-on-demand business model. This technology leap addresses a giant opportunity to use meaningful data for improved patient care.”
In December 2020 the device and company received approvals from the U.S. Food and Drug Administration. Two months later, it was being used in surgeries.
“It’s kind of an exciting advancement,” Smith said. “In the past we just put in a block that did not necessarily provide optimal correction of the deformity did not really contact the bones optimally and didn’t really favor the healing process like the new implant does.”
The technology to make the implants was not readily available until the development of 3-D printing for titanium structures, Smith said.
“To be able to 3-D print titanium cages is relatively new. It’s been around for a just a few years,” he said. “Before that technology we couldn’t really create the unusual surfaces and shapes that match each individual patient.”
Smith said the device promotes fast healing and recovery and creates fewer complications from surgery and reduces the need for additional surgery
“The two goals of spinal deformity surgery are to get realignment and ultimately get the bones to heal together solid, and this actually helps with both of the goals,” he said. “It’s an exciting advance, and it’s pretty exciting that U.Va. is on the forefront of it.”
In July, the company announced it was working with the International Spine Study Group Foundation to study adult spinal deformity and collect data on surgical treatment with similar devices.
Long term outcomes data will be collected to determine how much, if any the devices improve patient outcomes and reduce surgical complications.
“There is a general trend to more personalized care in medicine. It makes sense that implants we would use for spinal surgeries to become more personalized as well,” Smith said. “I have a feeling more and more surgeons are going to be using the implant. The technology is good and it’s going to prove beneficial.”