Without a 3D workflow and the technology and support of 3D Systems, the alternative path to treatment would have involved bending a standard bridging reconstruction plate by hand until it approximated the desired form. However, with this conventional approach there would be no way to optimize the placement of the screw holes or harmonize screw hole placement with the rest of the reconstruction plate design, which could weaken the plate’s resistance to material fatigue fracture in the bridging area.
“Control over screw hole placement was of decisive importance in this case because the patient’s body no longer has the means to repair the bone, as is needed for the stable bio-integration of the screws, even with the use of an osteo-myo-cutaneous flap,” said Dr. Sun. “In jaw surgery there is no room for the slightest amount of malocclusion, so the 3D reconstruction had to be perfect, and the force bearing plate had to be as solid as possible to withstand the loading. That would not have been possible to the same extent without a 3D printing approach."
Once 3D Systems had been selected to assist Sam’s surgeons, two engineers from 3D Systems’ Healthcare team were assigned to the case and accompanied the entire procedure, from planning all the way to the operating room. After Sam’s medical imaging data had been transformed into a three-dimensional digital model, UZ Leuven printed a physical anatomical model of the jawbone in separate components using the 3D printer housed in their lab. Together these plastic jaw components were used to format the surgical cutting guide and design the reconstruction plate.
The 3D printed cutting guide allowed the surgeons to smoothly transfer their surgical plan into the operating room and precisely remove the remaining piece of jawbone. Prof. Dr. Schoenaers and Dr. Sun also designed the reconstruction plate, and provided the 3D design to 3D Systems for production and finishing as specified.
The medical team also used their early 3D printed anatomical models to pre-determine the placement and position of the screw holes. Screw holes for these types of reconstructive plates are typically located where the jawbone is the thickest and strongest, which means they should align as much as possible with the posterior cortical bone-edge of the ascending ramus of the lower jaw. To accommodate this ideal placement, multiple screws were required at different orientations. To ensure the screw threads were as sharp and accurate as possible, the final 3D printed reconstruction plate was milled as part of post-processing.