3D PRINTING IN SPINAL SURGERY
Firefly lights the way for spine surgery with 3D prints
Spinal Elements, the California-based company responsible for helping make medical-grade PEEK plastic the industry standard for spine surgery implants, is working with Mighty Oak Medical’s custom made Firefly Technology. Firefly provides 3D printed guides for surgeons that are designed to match the exact contours of a patient’s vertebrae.
The guides are created using images form a patient’s computed topography (CT) scan, which is rendered in a CAD program, then 3D printed in a plastic that received FDA approval in January of this year. The guides are used to improve a surgeon’s ability to navigate the placement of screws within a spinal-fusion operation. Such an operation is done when bone and tissue in the spinal canal narrow, squeezing nerves or the spinal cord, often the cause of fractures or a condition. Spinal fusion is considered to be major surgery, and often takes several hours to complete. These guides are one solution to help speed up the operation process, improve accuracy and therefore reduce some of the risk and discomfort involved. They also don’t require any intraoperative imaging (iMRI scans) that are not only expensive, but can also cause damage through exposure to radiation.
Judging by Spinal Elements’ success in the field of spinal surgery, Mighty Oak Medical are in good hands, and this Firefly Technology could yet become a standard practice around the globe. Heidi Frey, President of Mighty Oak Medical, commented the following on the partnership:
We are excited to partner with Spinal Elements on this technology. We feel confident that once surgeons experience the ease of use and accessibility of the FIREFLY® system, they will gravitate towards predetermined screw sizes and trajectories, implemented with 3D printed patient-specific guides, as a preferred course of treatment for their patients. Spinal Elements, being a technology leader, is a natural partner choice for us to market this technology.
Spinal Elements is currently exhibiting Firefly Technology at the North American Spine Society (NASS) Annual Show in Boston, running until Saturday the 29th October. It is the second company to be exhibiting 3D printing technology that we at 3DPI have come across. Medical giants Stryker are also exhibiting their 3D printed Tritanium lumbar support cages at the show.
Design and fabrication of 3D-printed anatomically shaped lumbar
cage for intervertebral disc (IVD) degeneration treatment
Spinal fusion is the gold standard surgical procedure for degenerative spinal conditions when
conservative therapies have been unsuccessful in rehabilitation of patients. Novel strategies are
required to improve biocompatibility and osseointegration of traditionally used materials for lumbar
cages. Furthermore, new design and technologies are needed to bridge the gap due to the shortage of
optimal implant sizes to fill the intervertebral disc defect. Within this context, additive manufacturing
technology presents an excellent opportunity to fabricate ergonomic shape medical implants. The
goal of this study is to design and manufacture a 3D-printed lumbar cage for lumbar interbody fusion.
Optimisations of the proposed implant design and its printing parameters were achieved via in silico
analysis. The final construct was characterised via scanning electron microscopy, contact angle, x-ray
micro computed tomography (μCT), atomic force microscopy, and compressive test. Preliminary
in vitro cell culture tests such as morphological assessment and metabolic activities were performed to
access biocompatibility of 3D-printed constructs. Results of in silico analysis provided a useful
platform to test preliminary cage design and to find an optimal value of filling density for 3D printing
process. Surface characterisation confirmed a uniform coating of nHAp with nanoscale topography.
Mechanical evaluation showed mechanical properties of final cage design similar to that of trabecular
bone. Preliminary cell culture results showed promising results in terms of cell growth and activity
confirming biocompatibility of constructs. Thus for the first time, design optimisation based on
computational and experimental analysis combined with the 3D-printing technique for intervertebral
fusion cage has been reported in a single study. 3D-printing is a promising technique for medical
applications and this study paves the way for future development of customised implants in spinal