NuVasive 3D Prints Microporous Surfaces and Optimized Lattices for Better Spinal Implants

NuVasive is a California-based medical device company specializing in spinal surgery. The company offers the gamut of tools surgeons need to plan and execute spinal procedures. From surgical planning software to implants and tooling for those implants, they offer the entire solution. They also have services for patient monitoring, X-ray enhancement, and a platform solution called Pulse. Minimally invasive techniques for the spine include: XLIF, ACDF and ALIF.

For us, the most interesting thing they have is Modulus. Modulus is a titanium implant that has been optimized for the right porosity for bone fusion. The company touts better “ongrowth, ingrowth…the greatest integration strength in 12 weeks,” compared to other implant materials. Furthermore, “the increased surface area and wicking capability of the porous surface improves blood-to-implant contact compared with traditional interbody implants.” Modulus was created to try to get as close to the modulus of bone as they can. 

The company achieved this by creating algorithms that design a proprietary structure to optimize the function of the implant. It is important work that can take existing techniques and procedures and enhance them. At the same time, one can patent and protect these types of structures and algorithms. This makes it exciting from a business point of view.

I always tend to complain that no one does any internal topology optimization and here is a titanium sponge that has been designed throughout with lattices to mimic exactly the stiffness of bone so that it can operate well with native bone—just enough to move when it should, but not too much to deform or too little that it breaks other areas within the body. This kind of engineering can be a revolution when compared to other parts, such as heatsinks, engines, and combustion chambers. To create a material for every part or application gives one the power to have the perfect properties in each case.

Additionally, parts feature optimized radiolucency to make implants easier to see on imaging and optimized the surface. There is a lot of hype with lattices right now and, in many cases, people use them because it’s a fad. Here, however, we’re seeing lattices used to great effect to reduce the volume of titanium required, as well as wettability, optimized viewability and stiffness of the part.

From a cost perspective, including print time and material usage, lattices make a lot of sense here financially. But, what is also happening is that lattices are implemented to create the real value of the product for clinicians and patients. The company relies on 3D Systems, specifically DMP Factory metal printers. 3D Systems has, for years, been active in design, development and the manufacturing of medical devices and have an outsourcing service manufacturing medical devices, as well.

We interviewed Ryan Donahoe, Vice President of Spine R&D at NuVasive, to find out more.

“NuVasive began investigating metal additive in 2016 as the design and manufacturing capabilities required to develop high quality, porous spinal implants, capable of enhancing bone growth, converged,” Donahoe said. “We currently have four product lines on the market utilizing metal additive manufacturing that support a variety of spinal fusion procedures in the neck and lower back, with more in the development pipeline.”

Why is it advantageous to use 3D printing? Is it faster to design and develop devices with 3D printing?

“NuVasive has recognized two primary advantages to 3D printing. Whether it is a plastic or metal 3D printer, rapidly prototyping complex geometries leads to more design iterations and faster commercialization timelines. The second advantage, specific to metal 3D printing, is the design freedom to create devices that can drive more value to the patient than traditionally manufactured devices.”

Has it changed the design of your devices?

“NuVasive developed a line of metal 3D printed interbodies that combine a microporous surface and an internal, optimized lattice structure that emulates the stiffness of bone. These characteristics result in devices that exhibit favorable X-ray imaging and creates a favorable environment for bone in-growth.”

What are the challenges when manufacturing with 3D printing?

“There are numerous challenges associated with 3D printing, from understanding design limitations, to developing production capacity, to ensuring final part quality. Specifically, one of the most challenging aspects of 3D printing with titanium for medical devices has been developing a fundamental understanding of machine performance. This is critical to designing safe and effective implants.”

Will 3D printing make more device designs possible?

“Absolutely, 3D printing is an enabling technology that we use at NuVasive to drive meaningful improvement to patient outcomes.”

What opportunities do you see for the technology in regards to personalized medical devices?

“Personalized medical devices are entirely possible with the trajectory of the technology. You see it already in other areas of orthopedics, but it’s still in its infancy within spine. The challenge will be aligning the economics with the potential clinical benefits, but there is a lot of opportunity to drive value with this technology!”

I really love this as an application. Here we’re seeing 3D printing unlock real value and advantage in a fast growing market that is also an exacting and critical application. This is a fantastic story of 3D printing bringing real change and improvement to lives and industries.