by Elizabeth Hofheinz, M.P.H., M.Ed.
In 2016, additive orthopedic production was responsible for nearly half a billion in revenue opportunities for printer hardware and software, materials, clinical engineering services, outsourced production, and other segments. This production area is estimated to grow at a 26% compact annual growth rate over the next decade, generating more than $1 billion in revenue opportunities by 2026.1
And while such additive manufacturing was initially limited to plastics and polymers, according to the American Society of Mechanical Engineers, now it can “produce reliable, high-performance, and FDA-compliant metal components from metal powders. This is of keen interest to orthopedic device manufacturers, who have long favored metals for their products, but could only produce them using subtractive machining methods, which are expensive and time-consuming.2”
With such promising developments on the horizon, a team of researchers from Rothman Orthopaedics and the Department of Orthopaedic Surgery at the Sidney Kimmel Medical College, Thomas Jefferson University in Philadelphia, Pennsylvania took a deep dive into 3D printing in orthopedics. Their Current Concepts Review article, “Technology and Clinical Applications,” appears in the May 20, 2020 edition of The Journal of Bone and Joint Surgery.
Co-author Pedro Beredjiklian, M.D. is Senior Vice President of Clinical Affairs and Chief of the Hand Service for Rothman Orthopaedic Institute. He told OSN, “Three-dimensional printing has been called the ‘second industrial revolution’ and we feel that this technology is poised to revolutionize medicine.”
Of the process, the authors wrote, “There are several ways of creating a file that can be modeled and printed. First, any object can be created de novo using computer-aided design (CAD) software. Second, a 3D scanner (or any camera with photogrammetry software) can be used to scan an existing object and convert it into a printable file. Third, there are online libraries (for example, www.thingiverse.com and www.3dprint.nih.com) that contain printable files. Fourth, anatomic models and guides can be generated from Digital Imaging and Communications in Medicine (DICOM) files. DICOM images from computed tomography (CT) and magnetic resonance imaging (MRI) scans contain a substantial amount of digital information, and as such can be used for creating high-quality patient-specific models and cutting guides.”
“Most of the 3D-printing processes involve the deposition of layers of the material that has been chosen to generate the print. For this to occur, the STL file has to be sliced into multiple layers, which the 3D printers can then deposit onto a printing plate…There are several software packages that can take an STL file and break it down into layers, which the 3D printer can use and deposit one on top of the other to generate the desired object…”
Preoperative planning and surgical training
Discussing one way that 3D printing is useful in orthopedics, the authors wrote, “A preoperative understanding of complex pathology aids in choosing the proper anatomic approach, provides an overview of the osseous work planned, and allows for customized implant selection and fit.”
Regarding the extent to which orthopedic trainees are exposed to 3D printing, Dr. Beredjiklian told OSN, “Not at all. We feel that 3D printing will have a huge impact on surgical education and training, and we now have several pilot studies evaluating this impact. Every hospital and residency program should have a 3D printer.”
As for what specifically may be helpful in training, the authors noted, “Accurate renderings allow for reproduction of age and pathology- specific (such as osteoporotic or dysplastic) bones, which Sawbones models (Pacific Research Laboratories) may not adequately reproduce.”
Intraoperative tools
Citing work by Sugawara et al, the authors mention that this team “developed 3D-printed aiming guide templates for fixation of the thoracic spine3. Templates that fit and locked onto the lamina during the procedure provided multistep guidance during pedicle screw navigation. This technology has the potential to lead to a reduction in the rate of iatrogenic injury to adjacent structures, radiation exposure, and operative time, although this has not been proven in the clinical setting.”
Arthroplasty guides
While 3D printed arthroplasty guides are now in use for the knee, hip, ankle, and shoulder, the authors indicate that it is unknown whether they actually improve outcomes.
Grafts
With nearly 1 million bone grafts performed annually in the U.S.4, surgeons are greatly in need of grafts or substitutes.
The authors of the Rothman study wrote, “…The development of bioactive scaffolds that can enhance bone growth and offer both mechanical and osteoinductive properties is therefore likely to meet an important clinical need. Three-dimensional bioprinting involves the use of tissue-specific cells, with or without biomaterials that function as an extracellular matrix. This bioink is then used to create a 3D object that is generated from a CAD file modeled to generate a printable STL file…”
Looking forward
Dr. Beredjiklian, also a Professor of Orthopaedic Surgery at the Sidney Kimmel Medical College of Thomas Jefferson University, was asked, “Of all the things that still need to be proven in a clinical setting with respect to 3D printing, what are the most critical and why?”
“We need to show that 3D printed patient specific implants are superior to standard implants in terms of functional outcomes and longevity,” he replied. “This will have a tremendous impact on the economics of health care delivery in orthopaedics.”
Concerning the availability of this technology, he told OSN, “The cost of 3D printing continues to drop as technology improves. Even if this technology is not directly available, its impact can be felt remotely (e.g. prosthetic limbs for children in third world countries).”
Co-author Alexander Vaccaro, M.D., Ph.D., M.B.A., President of Rothman Orthopaedic Institute, told OSN, “In spine surgery we hope to someday have a mechanism to print spinal implants on a demand basis off preoperative advanced imaging studies to improve outcomes and reduce complications.”
Additional authors include: Mark Wang, M.D., Ph.D., Kevin Lutsky, M.D., M.B.A., and Michael Rivlin, M.D.
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