3D Medical Application Center Delivers Custom Implants Faster with Geomagic Freeform
One of the many facilities that use Geomagic® Freeform® is the 3D Medical Applications Center at Walter Reed Army Medical Center, located in Washington, DC. The Center is the only one of its kind to serve DOD and VA hospitals countrywide. They create custom models and implants required to correct to injury and disease-related problems. The center’s director is Dr. Stephen Rouse, a retired military dentist. His partner is Senior Medical Engineer Dr. Erge Edgu-Fry, an atomic physicist by training. The two manufacture medical models primarily used for surgical planning. However, a considerable part of their work involves designing implants for soldiers wounded overseas.
The demand for implants is high and the correct fit is critical. Dr. Rouse and Dr. Edgu-Fry’s existing process included systems that could be hard to use and time consuming; parts could take several days to model. They wanted a faster, easier (and therefore less costly) way to create custom implants that would also allow them to produce more refined parts.
The process to create a custom implant begins with CT and MRI scans. These systems produce “image slices,” which then need to be converted into a 3D model and output as an STL file. In the case of a damaged skull, the center can then import STL skull data into Geomagic Freeform modeling software. From here, they quickly create and manipulate a NURBS surface that encompasses the defect area. The model matches the curvature of the remaining skull in addition to pre-injury photographic images of the patient. The NURBS surface is then thickened and converted to virtual clay. Using Freeform’s digital sculpting tools and Boolean operations, the original skull data is then used to remove geometry from the patch so it fits perfectly at the beginning edge of the defect area. Freeform digital carving and smoothing tools remove any remaining undercuts on the back side of the patch and smooth the entire patch.
The picture on the left shows a damaged skull that has been fitted with an implant using Geomagic Freeform. The smaller version shows the skull prior to the implant being placed. This very example would have taken Dr. Edgu-Fry about 1-2 days to model with their previous software, but with Freeform she was able to complete it in 2-3 hours.
Once the model is completed, the doctors create an epoxy resin prototype on a 3D Systems ProJet 7000. This prototype is then sent to a lab that uses the prototype to mold an implantable part, quite similar to the way dentures are made. Once this part has been completed, the center either delivers it by hand or sends it overnight.
Dr. Edgu-Fry first heard about Geomagic Freeform at the end of July 2005. She received eight hours of training later that summer. By the fall of 2005, she was using the system daily, and she had completed prosthetic parts for four skulls, a couple of them already on their way for surgical implantation. With a small amount of training, she became very productive and believes that tools like Freeform are ideal for rapidly creating custom implants. Now that the doctors are becoming more proficient on the system, they have started to use its techniques to produce other types of projects, such as a pelvic implant that they are currently working on.
With the Freeform system in their workflow, Dr. Rouse and Dr. Edgu-Fry estimate that it will take 2-5 hours per part, a significant time-savings over their previous method, which took two days or more to produce a hand-modeled implant. “Since using haptic devices with more effective software, such as Freeform, is so easy, I’ve been able to complete implants for skulls faster and that are more refined than before. Now I can easily set whatever thicknesses I need and make smoother parts,” said Dr. Edgu-Fry.