With more than 185,000 lower limb amputations every year in the US alone, and over 1 million carried out worldwide, prosthetics specialists struggle to keep up with the rising demand for their services.
The traditional method of creating prosthetic sockets, the part of the device that interfaces with the patient’s residual limb, involves plaster casting, hours of work, along with ample finesse and experience.
Specialists, such as those at Sanitätshaus Klinz orthopedics clinic of Bernburg, Germany, still employ plaster casting and other analog methods in their work, but for challenging projects, they frequently turn to their 3D scanner, the Artec Eva.
3D scanners have been a leading tool among healthcare practitioners. The Artec Eva quickly delivers color 3D scans with accuracy below a millimeter, making it ideal for capturing the organic surface measurements of patients’ residual limbs and other body parts.
The specialists also make use of the Artec Space Spider, for projects with intricate details that demand the utmost in precision. Originally developed for use on the International Space Station, the Space Spider is a popular choice among designers, engineers, and researchers in many fields.
The specialists at Sanitätshaus Klinz developed a unique prostheses for a patient. Wolfgang K. lost a leg after a forklift crashed into him, shattering his foot. When it came time for Wolfgang to get a new bath prosthesis, he was looking for one that could be used in the shower or while swimming.
It would need to be both waterproof and corrosion-resistant, even in salt water environments. When biomedical engineer Lisa Pabst saw his request, she decided to offer him something even better.
From their discussion, Pabst understood that Wolfgang’s passion was diving. So, she, along with Wolfgang and her colleague master orthopedic technician Carsten Suhle, came up with the idea to create a unique bath prosthesis with a maritime design that wouldn’t merely be cosmetic, but rather to have the prosthesis itself be a one-of-a-kind, maritime-themed design object.
“We wanted to pursue a different approach,” said Pabst, “to see whether it would be possible for us to integrate a prosthesis into our new design rather than adapting the design to an existing prosthesis.”
Their goal was to combine all the water-resistant durability of a bath prosthesis with the esthetics of a cosmetic prosthesis, so when it’s being worn under long pants, no one can tell that there’s a prosthetic limb underneath. All the cosmetic elements of the prosthesis would need to cover and protect the mechanical components of the device.
“We came up with the idea of using an octopus,” Pabst said. “The body of the octopus covers the upper part of the prosthesis, while the tentacles mimic the shape of the lower leg. A nostalgic diving helmet, entwined in tentacles, was added at the ankle. The ankle joint can be operated via the side openings of the helmet.”
The most vital part of any new prosthesis is the shape and fit of its socket, with a design that’s unique to each individual patient, where even a mildly incorrect fit can often result in patient discomfort and biomechanical dysfunction leading to future injury.
To help achieve a seamless fit for the new socket, Pabst used the Artec Eva to scan all of the surface geometry of Wolfgang’s residual limb in less than a minute. She also scanned his other leg, in order to use its precise volumetric and surface measurements for creating the shape and dimensions of the new bath prosthesis.
Right after the scanning session, prior to exporting the 3D meshes to Geomagic Freeform, the scans were processed in Artec Studio software.
The scans were aligned and registered, then merged together into one object. Finally, the texture was brought in and applied to the mesh. In Freeform, Pabst designed the prosthetic socket and sculpted the cosmetic elements of the design to life.
After importing and arranging the meshes in Freeform, Pabst built up the prosthetic shaft, shaping it to the adapter and preparing the design for the functional elements. She then shaped the outer dimensions of the tentacles to achieve the same overall circumference of the lower leg.
At this point, Pabst created the tentacles’ suction cups, then connected the shaft, octopus, tentacles, and diving helmet. After several other steps, she embossed the design with the Klinz logo and the patient’s name.
After 3D printing the exterior components of the new prosthesis, they were merged with the mechanical elements of the device and locked into place.
Pabst commented on the pivotal role that 3D scanning has gained in modern orthotics and prosthetics design, “Whenever you need to create an orthosis, or an upper- or lower-body prosthesis, with high-tech or low-tech materials, first you absolutely must have accurate measurements of the patient’s body where the new device will connect.”
“Without this foundation to build on, eventually serious problems will arise, from the fit of the device, to the patient’s physical responses to it. By starting off with Artec scans, every device we produce looks exactly like the other side and a natural extension of their own body. The difference this has made in our work is truly significant.”