3D Spinal Implants: A Glimpse into the Future

In their search for the latest medical advancement to restore health to their patients’ spines, surgeons may start looking to a printer for answers. A 3D printer, that is. 3D printing technology allows a surgeon to design a prosthetic that fits perfectly in a patient’s body. Given the sensitivities of the spine, the possibilities for 3D spinal implants are especially intriguing.

Dr. Ralph Mobbs, a neurosurgeon in Sydney, Australia, is the first surgeon in the world to implant a 3D-printed spinal implant. After removing a tumor in the neck of a patient with chordoma, a rare form of spinal cancer, he inserted the perfectly-fitted implant to successfully restore stability to the patient’s spine.

Dr. Mobbs believes many more procedures of this type are on the horizon, and he shared his thoughts on 3D spinal implants with SpineUniverse below.
The above photo show a 3D custom implant to reconstruct a vertebra destroyed by a spinal tumor. Used with Permission, © Neuro Spine Clinic, Dr. Ralph Mobbs, Neurosurgeon, NSW Australia.

What are the main benefits to using 3D spinal implants versus other implants (such as an artificial disc)?

Dr. Mobbs: The majority of spinal implants are inserted to stabilize the bones of the spine to correct a problem, then fuse the bones together. We use “off-the-shelf” implants, which are made in a variety of sizes and shapes, to suit most spinal problems that we face as surgeons.

At times, we see unusual problems, such as a congenital deformity, severe spinal degeneration, or destruction of the spine from a tumor. These issues are difficult or impossible to reconstruct with an off-the-shelf implant. This is where 3D printing of customized implants, which are made specifically for the patient, comes into its own.

The main benefit of 3D spinal implants is that we can print a unique implant that is specifically designed to fit perfectly into a defect to correct a problem. Looking ahead, there is currently research being performed on 3D printing of artificial discs.

What are the primary limitations of 3D spinal implants?

Dr. Mobbs: The drawbacks of 3D implants can be boiled down to four things:

1. Cost. As the implant is designed and printed for a single patient and operation only, it can be costly when compared to an off-the-shelf implant.
2. Time to plan and print the implant. The initial patient-specific 3D printed implants took us two to three months to design and print. With improvements in computer-aided design (CAD) software made specifically for medical design, along with faster printing machines, this time has been significantly reduced.
3. Regulatory framework for having customized prosthesis approved. There is still no standardized framework for approving patient-specific spinal implants.
4. Surgeon acceptance. Many surgeons do not feel comfortable with designing and implanting a customized spinal prosthesis. This will change rapidly as the demand for patient-specific implants grows.

The above photo show a 3D custom implant to reconstruct a vertebra destroyed by a spinal tumor. Used with Permission, © Neuro Spine Clinic, Dr. Ralph Mobbs, Neurosurgeon, NSW Australia.

Is there a difference in durability in a 3D spinal implant compared to more mainstream spinal implants?

Dr. Mobbs: No, there is no issue of durability or biocompatibility of 3D spinal implants. Patient-specific spinal implants are made of exactly the same materials as off-the-shelf implants. The big difference is that 3D-printed implants are made to fit perfectly for a specific patient and a specific problem.

Given how new this technology is, how do you discuss 3D spinal implants with patients who may be skeptical?

Dr. Mobbs: I have performed multiple cases using 3D printed prosthesis, so I show patients models of previous operations that I have done. After they see a model of a complicated reconstruction, they get it. I explain the significant benefits and that the materials in the implant are the same as other approved implants.

Are there situations related to spine treatment or special patient considerations where a 3D spinal implant would not be appropriate?

If a patient requires an urgent operation, and we do not have time to plan, design, and print a customized implant, then this technology is not appropriate. But, in the future, it’s likely that every hospital will have a printer, and customized implants may be available in several hours or less.

To move this technology forward, there needs to be advances in software to speed up the CAD design process to make it accessible to spine surgeons anywhere. This is real exciting stuff!
The above photo shows 3D printed vertebral replacement implants in preparation for surgery on a cancerous spine. Used with Permission, © Neuro Spine Clinic, Dr. Ralph Mobbs, Neurosurgeon, NSW Australia.