Though not broadly adopted yet, 3D printed spinal implants have the potential to change the landscape for spine-related surgeries, as they can be customized to fit the patient’s anatomy perfectly—unlike more commonly used off-the-shelf implants. However, a number of challenges still stand in the way of the broad implementation of the bespoke 3D printed implants, largely related to cost, complexity of process and standards.
Fortunately, innovative medtech, 3D printing and software companies are working to break down these barriers to make 3D printed spinal implants viable alternatives to more traditional implant systems. For instance, Irish Manufacturing Research (IMR) recently teamed up with generative software developer nTopology and UK-based metal AM company Renishaw to showcase the benefits of 3D printing spinal implants.
The partnership, which leveraged Renishaw’s metal AM capabilities, nTopology’s design and optimization software and IMR’s spinal implant design, demonstrated how the production process for spinal implants can be streamlined, facilitating the transition from implant design to final production.
The implant produced through the partnership is a titanium spinal device for the cervical spine which integrates a complex internal lattice structure generated by nTopology’s platform. The internal lattice, a feature which would be impossible to produce using traditional manufacturing processes, allows the implant to be more lightweight without sacrificing strength and performance. Moreover, 3D printed implants can also be designed to have porous external features that closely mimic real bone and promote bone regrowth in the body.
“AM can be used to manufacture spinal implants with lattice structures, which cannot be achieved with conventional manufacturing techniques,” elaborated Ed Littlewood, Marketing Manager of Renishaw’s Medical and Dental Products Division. “An implant with a lattice structure is lightweight, can be optimized to meet the required loading conditions and has a greater surface area, which aids osseointegration. Therefore, AM implants can be designed to mimic the mechanical properties of bone, resulting in better patient outcomes. But all of this comes to nothing if you do not have the tools to create the design.”
Matt Rohr, Application Engineer Manager at nTopology, added: “Traditional CAD tools weren’t built to design complex lattice structures; the job would be difficult or even impossible. nTopology was designed to complement existing workflows and make the job easier. We cut the design time of complex structures from days to minutes which was a crucial component in helping this project run to schedule.”
The streamlined design and production process for the 3D printed implants are obvious benefits within a medical context, where time is often vital. Further, because the 3D printed implants are customized to the patient and have optimized designs, they are easier to implant, requiring shorter surgery times and fewer revision surgeries down the line.
“Renishaw worked tirelessly with us on improving the AM process for producing the spinal implants,” said Sean McConnell, Senior Research Engineer at IMR. “Together, we designed a set of experiments that yield the most appropriate parameter settings for the product. As a result, we reduced the amount of post processing required on key features of the implants by a factor of ten.”
In addition to working on the 3D printed spinal implants with nTopology and IMR, Renishaw also recently teamed up with the University Dental Hospital of Wales to 3D print custom maxillofacial implants and surgical guides.
Overall, the improved process for 3D printing spinal implants could help accelerate the adoption of the bespoke implants for treating patients with degenerative disc diseases, herniated disc, spondylolisthesis, spinal stenosis, osteoporosis and other spinal conditions.