How many times did you go in for a fitting before your prosthesis finally fit right? It usually takes several fittings and adjustments to get a socket fit that's great, but probably not perfect. The typical sockets being made today aren't easily adjustable once laminated. But Lizbeth López, a Brazilian biomedical engineer who lives in Mexico, saw a way to change that. She created a custom transtibial leg socket using 3D printing technology.
“The main objective of this work was to fabricate a complete functional prosthesis, in this case oriented to transtibial amputees as the first group of test patients,” López told 3dprint.com. “The project began as a personal motivation to design and fabricate a prosthesis well adapted to the health needs of the patient.”
Proponents of 3D printing believe the technology should be used to print prostheses that more accurately conform to the limbs they will attach to. The technology is already being used to make prosthetic hands and fingers, but 3D printing hasn’t quite entered the lower-limb prosthetics market. Too many still question whether 3D printed prosthetics for lower extremities can withstand weight and pressure.
López explained that before the printing she tested the socket design so she could be confident about its mechanical resistance. Once the engineering was approved, they began a more than 20 hour process of creating the custom component.
"We decided to use a laser scanner and CT to capture the stump of the patient,” López explained. Later, the data from the CT was used to create a digital 3D reconstruction which was then compared with data from the laser scan. The next phase of the design process was based on the real anatomical data of the man who would wear it. After those initial scans were taken there was no need to meet again until the initial fitting.
On that day, the results surprised everyone. Although one screw did need to be adjusted, it was completely comfortable according to the man who wore it. He was used to trying on the prosthesis over and over in search of the right socket fit. Sometimes he grew frustrated while waiting days between fittings. A 3D printed socket took all of that out of the picture.
Lopez's success may eventually make the need for multiple fittings a thing of the past.
“That’s really good because then we have a great approximation to the fantastic and ‘futuristic’ idea that it’s going be possible to adapt many prosthesis to many patients in one single day," she said.
Check out the video of López’s patient trying on his prosthetic leg on 3dprint.com.