Potential of 3D printing in prosthetics

The power of 3D printing has been felt far and wide in a vast number of sectors in recent years. The field of prosthetics, or limb extensions/replacements, is no exception to this. A traditionally manufactured prosthetic can cost upwards of several thousand dollars and must be highly customized to fit a unique user. There is also the issue of growth, as prosthetics designed for children will be outgrown in a number of months, racking up further costs.

The design freedom granted by additive manufacturing has been known to come in very handy for applications such as this, as the technology is not limited by the geometric constraints of a production line and conventional manufacturing methods. Design iterations can be made on the fly, and pivoting mid-product lifecycle doesn’t set the project back all that far.

Virtually anyone with a dream and a 3D printer (and some CAD software) can produce their own prosthetics, with basic assemblies costing less than around $100. Of course, for a long-lasting and reliable piece of kit, costs may end up significantly more than this but even higher-end products will benefit from material and time savings. In fact, the concept of 3D printed prosthetics, although niche, makes up large parts of business models for certain specialist companies, and is the topic of extensive research - we'll have a look at a few of these cases shortly.

3D printed prosthetics in the industry

Just last year, UNYQ, a San Francisco-based company specializing in 3D printed medical wearables, announced the launch of the UNYQ Socket, the company's very own 3D printed prosthetic leg socket. The UNYQ Socket is one of the various products that the company has since added to its Prosthetics Wear line, intending to eventually provide a complete, 'aesthetically unified' prosthetic leg product by the end of 2021.

For context, a prosthetic leg socket is the section of a prosthesis that attaches to the residual limb. The UNYQ Socket has been implemented with various features designed to provide benefits for both the amputee and the clinician that are not present in traditional prosthetic leg sockets.

Using 3D printing, the socket is designed to be lightweight, replacing the metal material often found in a traditional prosthetic leg, whilst also improving on the style of existing options. Furthermore, the 3D printed prosthetic leg socket has also been integrated with sensors to record the user's activity, such as the number of steps and potential calories burned, allowing users to keep track of their fitness and exercise.

Elsewhere, New Zealand-based medical startup myReflection has previously announced the development of personalized breast prostheses for cancer patients post-mastectomy, using 3D scanning and 3D printed molds. The prostheses are made from a 3D torso scan and are designed with an inner core and an ISO-certified outer silicone, meaning they’re fully compliant with stringent medical regulations.

Since similar traditional prostheses don't last all that long, users are often hit with concern when deterioration sets in, as they'll have to pay for the next one out of pocket. The material used by myReflection is reportedly very stable, elastic, and tear-resistant, so it can last around for years and is designed to be loseable and ultimately replaceable.

Pediatric prosthetics

The world of pediatrics, or child care, is where 3D printed prosthetics really shine. Researchers from the University of Lincoln, UK, have previously developed a prototype for a 3D printed, sensor-operated prosthetic arm designed for children under two-years-old. Dubbed the Soft-Grasp Infant Myoelectric Prosthetic Arm (SIMPA), the prosthetic was created using 3D scanning, additive manufacturing, and an armband-based Surface Electromyography (sEMG) system.

What makes the SIMPA special is that it is a myoelectric prosthetic, a type of prosthetic controlled by electrical signals in the muscles, and commonly given to adults but not children due to the difficulty and expenses of down-scaling. This is due to the rate at which a child grows, which calls for the constant replacement of such a device. To add to this, in cases where young children with upper limb amputation have prosthetic devices, the child is prone to develop their own methods of grasping objects which can limit their motor neural skills.

The manufacturing technique even has its uses in warzones. Syria Relief, a UK-based charity working in Syria, has previously appealed for the UK’s Department for International Development (DFID) to provide funding for 3D printed prosthetics for children affected by conflict.

It is estimated that over 30,000 people have lost limbs in the Syrian conflict, and the average number of people per month receiving a prosthetic limb is 60. For children alone, a traditionally manufactured electronic arm costs an eye-watering £1000 and can take weeks to produce. Syria Relief believes that a one-off investment in 3D printers can help alleviate pressure off doctors, and meet the needs of prosthetic users in the country.

The future of 3D printed prosthetics