The use of 3D-printed spine devices and implants has grown in recent months, allowing for more customized surgical planning. Many spine surgeons see potential in 3D-printed technology but also foresee challenges that will need to be addressed to ensure its success.
Here's how 15 spine surgeons see 3D printing evolving in the next three years:
Note: Responses were edited for style.
Alan Dang, MD. University of California San Francisco Medical Center: More and more residents and fellows are using 3D-printed precision anatomical models for patient education and surgical planning, and these models will continue to see increased use, particularly in complex cases. On the implant side, which is more broadly applicable, 3D-printed implants will mature in the same way traditionally manufactured implants did. Most 3D implants today are made of titanium alloy. Over the next three years, there will be more latticed and 3D-printed interbody devices made with polyaryletherketone-family materials, along with surface enhancements. Spine surgeons will then have wider implant choices to choose from.
Peter Derman, MD. Texas Back Institute (Plano): 3D printing has allowed for the creation of spinal implants with unique structures and surfaces for optimizing fusion. I think that the next step in the utilization of this technology will be the widespread manufacture of truly patient-specific implants. While "off-the-shelf" options generally suffice, 3D-printed implants will feature geometries tailored to a patient’s anatomy and the desired correction. Stiffness could be modified based on bone density. However, logistical hurdles must first be addressed. These include developing systems by which patient imaging can be obtained by manufacturers and translated into implant designs, likely with the aid of artificial intelligence. The implants then need to be printed, sterilized, packaged and shipped, and the entire process has to occur within a reasonable turnaround time. Despite these challenges, I think that it’s just a matter of time before surgeons are able to provide 3D-printed custom implants to their patients.
Samuel Joseph, Jr., MD. Joseph Spine Institute (Tampa, Fla.): In the next three years I see 3D printing as growing significantly to fill the need of patient-specific implants. This will be carried into pedicle screws, cervical plating, as well as cage design. With better technology, including AI and preop planning, we will be able to develop implants that reduce OR time, cost, as well as allow us to restore appropriate alignment with reduced complications.
James Harrop, MD. Thomas Jefferson University Hospitals (Philadelphia): I think 3D printing will have an expanding role in spine surgery in both the short, and more importantly, in the long term. I believe technology will advance in the next three years; however, it will really expand and develop as we better understand bio materials. In addition, the improved understanding of sagittal balance and design of patient-specific implants will be synergistic. The hope is that with robotic technology, improved understanding of deformity anatomy and optimal patient-specific sagittal and coronal balance, the ability to create patient-specific implants will accelerate the field. In the future, we will evolve away from picking a product off the shelf to designing a specific operation for a specific patient and use a custom implant.
Nitin Khanna, MD. Orthopedic Specialists of Northwest Indiana (Munster): 3D printing has to be viewed as an important piece of the puzzle as we march toward truly patient-specific spine surgery. The ability to print a "generic" 3D interbody cage is just scratching the surface of this technology. As we integrate machine learning, 3D preoperative planning with patient- specific rods and sagittal alignment goals,we will soon be able to also identify and 3D print the ideal cage from an end plate coverage, stiffness match and coronal/sagittal-specific parameters standpoint.
As the technology progresses, patient-specific 3D disc replacements can be built with the ultimate goal to build a truly biological disc replacement. One day in the not-too-distant future: tissue engineering after expanding a patient’s own cells and 3D print tissue that can rebuild a human disc. This patient-specific human disc can then be replaced, restoring the physiologic dynamics to the spine.
Ronald Lehman, MD. Columbia Orthopedic Surgery (New York City): 3D printing will continue to evolve in spine surgery over the next few years in several ways. We have seen current implants that rely on 3D printing to better replicate the microarchitecture of the end plate, (and interdigitate and attach to the end plate itself) to facilitate fusion. However, the ability to design, plan and print patient-“specific” implants will only continue to address a need that we have. This will be beneficial for trauma, tumor and deformity cases in particular, as we use similar 3D-printed, patient-specific implants in orthopaedic trauma and tumor for years. I was first introduced to this technology while at Walter Reed Army Medical Center during the wars in Iraq and Afghanistan, as it was used for addressing critical size bone defects and for amputees. The advances in surgical planning software will further allow us to determine patient-specific goals for spine surgery, educate and train on the surgical plan and design and produce 3D-printed implants or guides to facilitate that plan and ensure it is executed accordingly.
Philip Louie, MD. Virginia Mason Medical Center (Seattle): I think 3D printing will continue to grow over the next three years and will serve as a useful adjunct to other technologies (especially navigation-based).
The unique ability that 3D printing provides in preoperative planning, as well as the benefits in safety and time-saving during surgery, have been well-documented. It is my hope that the field of spine surgery will follow the footsteps of other specialties that are now incorporating customized implants based on a patient's unique anatomy, especially in the deformity setting.
As surgeons continue to improve radiation safety and minimize exposure, 3D-printing capabilities will continue to provide a lower cost and effective platform to aid in surgery. Ultimately, the customization of implants and the ability to complement other spine surgical technologies to improve the safety and value of spine surgery will be what I am most intrigued about.
Matthew McDonnell, MD. University Orthopaedic Associates (Somerset, N.J.): 3D printing has a number of emerging uses in the field of spine surgery. We have the capability to print and precisely reproduce a model of the spine which can be used for preoperative planning purposes for complex spine deformity and tumor cases. A surgeon can actually hold an exact replica of a patient's spine in his or her hands, prior to a surgical procedure, to have a better understanding of a patient's unique anatomy. Additionally, 3D models can be used in the setting of resident and fellow training. Spinal implant companies are already 3D printing titanium metal cages. The 3D printing process allows them to build implants with complex geometries and porous surfaces that facilitate quicker and improved spinal fusion rates. I suspect in the future, 3D printing will be used to produce custom implants that are patient- and anatomy-specific. If custom implants can be introduced into the field in a way that allows for improved patient outcomes, while decreasing costs, the use of this technology is sure to expand in the upcoming years.
Issada Thongtrangan, MD. Microspine (Scottsdale, Ariz.): I see the continuing growth in 3D-printed spinal implants. In my opinion, the ideal implant must have an appropriate porosity for the bony in-growth and on-growth as well as matching the modulusticity of the bone. However, advanced technology is not cheap, but I predict that the cost will go down with the competitive nature of the market.
Robert Watkins, Jr., MD. Marina Spine Center (Marina del Rey, Calif.): 3D printing will become more prevalent as costs come down and speed of production increases. The ability to create unique shapes, with unique surfaces and preservation of large gaps for interbody fusions makes the additive production technique beneficial compared to the typical subtractive techniques of current production.
Usman Zahir, MD. ScopeSpine - The Orthopedic Group (Dulles, Va.): 3D printing will continue to help in the transition from moving spine surgery from the inpatient to outpatient ASC setting. Apart from the benefits in custom implant design and reduced need for storage and inventory I find promise in the use of small 3D-printed spine molds for intraoperative targeting for instrumentation. Custom spine targeting molds help reduce operative time and radiation exposure in performing less invasive midline approaches taking into account each patient's unique anatomy. Many robotic and navigated spine platforms are too expensive for many ASCs. 3D printing offers a very practical, efficient and cost-effective solution.
Brian Gantwerker, MD. Craniospinal Center of Los Angeles: With the advent of 3D printing, spine surgery has been poised to fully adopt this exciting technology. While 3D printing has been promised to revolutionize the field of spinal surgery, it has been somewhat slow to come into its own. Currently on the market, there are several manufacturers that use 3D printing with the promise of better bone conduction and stronger implant integrity.
In the next three years, I believe we will see wider adoption among the "big box" manufacturers. What we need to see is the wide availability of custom 3D implants. In conjunction with robotics, low-cost, better-fitted interbody and vertebral body/corpectomy cages would make implant fit better and reduce the likelihood of different implant complications, such as pseudoarthrosis, kick out or windshield wiper failures. Along with the precision of the robotics doing the tissue removal, 3D custom implants could significantly positively impact patient outcomes.
Charles Sansur MD. University of Maryland School of Medicine (Baltimore): 3D printing in spine surgery will enable us to provide better options for our patients in a variety of ways. It provides us with the ability to match the patient’s bone quality with the modulus of the implant. We will have a greater ability to fill voids in oncologic cases as well as complex deformity cases. The improved porosity and surface texture available in 3D-printed implants will ultimately result in better fusion rates and hopefully better outcomes in our patients.
Miki Katzir, MD. University of Nebraska Medical Center (Omaha): As a spine oncology neurosurgeon, I perform corpectomies, partial or complete, through both intralesional and en bloc fashion. I don’t know how economical it is but implanting a custom-made 3D printed vertebra could be beneficial specifically in those patients with abnormal anatomy like severe kyphosis or scoliosis at the area, for which there isn’t a perfect fitting standard cage.
I do think that the currently available cages fit OK to 80 percent of the patients, but for the remaining 20 percent we must be creative. Currently I’m using polymethylmethacrylate cement for those patients, Polymethylmethacrylate is easily moldable inside the corpectomy cavity, but it comes with its disadvantages, as: not promoting fusion across the space, does not anchor into the endplates and rarely, exothermic injury to the surrounding structures. Cancer patients live longer and longer in these days where we have very advanced immunotherapy and stereotactic body radiotherapy. It seems like the current cage technology lags. An interesting thought I recently started thinking about is a 3D printer located in the OR core, for example after we are finished with the corpectomy, we scan the patient with our mobile CT scanner of our choice, transfer the data to the printer and in 20 to 30 minutes we have our custom made perfectly fitting cage. Only the future can tell whether it is the future or just a dream.
Arya Varthi, MD. Yale School of Medicine (New Haven, Conn.): I believe that 3D printing will have an expanded role in both spine surgery over the next three years. From an educational standpoint, 3D printing can be used to create models that allow for trainees to better understand anatomy and hardware placement. From an operative standpoint, there are several uses of 3D printing. Patient-specific pedicle screw insertion guides can be utilized to improve the speed and accuracy of screw placement. 3D printing can be used to create models that surgeons can study preoperatively in large deformity cases. The possibility of more widespread use of 3D printing technology to create patient-specific implants exists over the next three years.
Note: This article was updated 9 a.m. April 30 to include additional responses.