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3D printing opens up new avenues for prosthetics. Sustainable, individual and efficient prostheses are created from powder. Partial Hand Solutions uses SLS printing and can better care for patients thanks to the digital workflow.
3D printing has fundamentally changed orthopedics. With this technology, it is possible to manufacture prostheses that are individually adapted to the patient. This works thanks to the digital workflow. The prosthesis is first designed digitally: the patient’s body measurements are taken using a 3D scan and transferred to a CAD program. The prosthesis is designed there and then only has to be transferred to the 3D printer. Depending on the type of production of the 3D printer, various post-processing steps are then necessary.
A new way to make durable and affordable prostheses is with SLS 3D printing. Selective Laser Sintering (SLS) takes place in a powder bed, usually using nylon powder. The powder is located in the so-called pressure chamber. Here, a laser melts individual particles of the powder layer by layer and thus combines them into a three-dimensional structure. The surrounding powder has a stabilizing effect so that no additional support structures are necessary. After printing, the powder must be removed in a special chamber so that it does not get into the airways. No other reworking is necessary, but the products can, for example, be painted if necessary.
New workflow improves patient care
Partial Hand Solutions specializes in the manufacture of prostheses for hands and arms. Founder Matthew Mikosz has been making patient-specific prostheses for many years, but has always faced the challenge of making an affordable but durable prosthesis. Until recently, he had an external supplier manufacture his orders using injection molding. However, they were never accurate enough, and production and delivery often took two weeks – and thus far too long.
Mikosz therefore turned to 3D printing, specifically SLS printing. Such devices have often been far too expensive for small and medium-sized companies. However, the manufacturer Formlabs recently launched the Fuse 1, an SLS printer that offers an alternative. The printer has a comparatively small footprint, is easy to use and affordable for smaller businesses.
Partial Hand Solution primarily manufactures prosthetic fingers for soldiers, but also supplies children with finger prostheses. Because of the very different stages of development, it is difficult to work with templates – so 3D printing comes in handy here. After modeling, printing and cleaning, Mikosz colors the prostheses in a solution of paint and hot water. Immediately afterwards they are ready for use. The finger prosthesis is very stable and durable thanks to the nylon powder. Of course, it can be moved individually by the little patient.
Efficient, sustainable and individual prostheses
As a small company, Partial Hand Solutions relies on being both sustainable and efficient. A large powder bed, from which products are only partially made, seems contradictory at first, but that is deceptive: On the one hand, the algorithm of the print preparation software arranges as many parts as possible in the pressure chamber, and on the other hand, the unused powder is removed when sifting, collecting and filtering the unused powder, collected and can be reused. This results in a recycling rate of 70 percent.
Mikosz can now do without the external supplier of the injection molds and manufacture the prostheses completely in-house. This also means that his patients will receive their prostheses faster. The products made from the nylon powder have similar thermoplastic properties as classic injection molded parts. They are also biocompatible and sterilizable.
Mikosz recently made an elbow prosthesis for a ten-year-old boy. Here, too, he used SLS 3D printing – prefabricated parts for adults are often used for prostheses for children. However, these make the prosthesis too heavy for children. Thanks to the 3D printed parts, the prosthesis became lighter and therefore more comfortable for his young patient to wear. SLS 3D printing opens up new avenues for prosthetics – this not least increases patient care.