Archives for posts with tag: amputees


One of the great challenges in biotechnology is interfacing synthetic materials with biological ones. Our bodies are designed with an extremely complex network of tissue, vascular, and neural structures to protect us and alarm us if there is something potentially dangerous to our system. If we sit for too long, for example, we feel discomfort and shift positions instinctively. If something is pressing against our leg and threatens to disrupt normal blood circulation, we perceive this threat with pain and pressure and respond accordingly.

Amputees and prosthetists have long been facing the issue of how to interface the residual limb with a prosthetic socket. Fitting for a prosthesis introduces a synthetic limb component to a biological one, and an improperly fitted socket can cause pain, pressure sores, and expose a residual limb to infection and tissue damage. And while there has been much improvement from the crude iron prosthetics that amputees once had to endure, there is still much room to improve to make the interface closer to a natural one.

One group at MIT has sought to address this disparity by developing a variable impedance prosthetic (VIPr) socket. Using MRI imaging and surface scanning techniques, researchers were able to find the tissue depth and where the socket was most likely to place pressure on the irregular bony areas of the residual limb. A socket was then 3D printed using this data to apply the least amount of pressure when fitted to the amputee.

After testing this socket on a below knee amputee, it was found that there was a 7-21% decrease in pressure on various bony areas of the leg compared to a regular socket during walking. While there is still no perfect socket or prosthetic interface for amputees, this is a step in the right direction to protect valuable and vulnerable human tissue.



What if there was a device which allowed amputees to feel their limbs again?

The loss of a limb or damage of the nerves that travel through our bodies can greatly diminish the human experience. The sensory system dictates how we respond to our environment, transmitting signals to and from our brains so we can move and feel. Pain, pressure, and temperature response are just some of the functions of the somatosensory system connected to our skin, allowing us to experience the world. In addition, our nerves have a motor component, sending signals from the brain to our muscles, telling them to work so we can move and perform tasks.

Nerves function much like electrical wires, transmitting signals between the brain and areas of stimulus, like an electrical wire between a socket and device. It is this electrical current which causes signals to be transmitted. After an amputation, the nerve is severed, not only disrupting the flow of a nerve signal, but also sometimes leaving amputees with a cruel phantom limb pain, as if the limb was still there. For those with limbs still intact who suffer from nerve damage, the physical limb remains, but its function is diminished without the motor and sensory signals being transmitted.

SENSY by Sensars is almost unbelievable in the amazing feat that it has sought to achieve, allowing amputees and those with nerve damage to feel again. Artificial sensors are implanted to connect to intact nerves, stimulating response in the brain as if there was an intact nerve in a limb. The sensors are connect to wires simulating an actual nerve, and those wires are implanted and connected to actual nerves within the body. Between the artificial sensors  and the residual nerve is an implantable neurostimulator which is bidirectional, sending and receiving signals from both the intact nerve and the artificial sensors.

The versatility of SENSY is also amazing. The company has a multi-functional product which targets both amputees and those with intact limbs who have nerve damage. There are 3 options, but the flow of information is essentially the same. A sensor (either from artificial skin, glove/sock, or “pacemaker”) sends a signal to a controller which is able to activate that signal to an implantable neurostimulator, which causes an electrical signal to communicate with the intact nerve. Once that communication is made, the connection is made between the artificial and biological part of the nervous system, and feeling is processed in the brain.

For amputees, Sensar has sought to decrease phantom limb pain and increase sensory feedback through sensors with a neuroprosthetic device which includes artificial skin. As we know, skin is very sensitive, and in this case will contain sensors which will prompt the prosthetic device to send signal through the artificial nervous system.

For those with intact limbs. the company is designing socks and gloves for those with upper and lower limb nerve damage. These socks and gloves contain sensors within the fabric which act essentially as sensitized skin, also sending signals to an implanted device which communicates with the intact nerves.

Finally, for those with an amputation but without prosthesis, the company has created an implantable pacemaker, essentially an excitable device like a sensor which also sends a signal to the nerve.

Go to the website to read about the full and brilliant description of this product, and watch the video for a visualization of how the artificial sensors are able to communicate with an intact nerve.Still in the prototype phase and not yet available for sale, SENSY will truly impact people’s lives once it is on the market.




In honor of the upcoming Maker Faire Bay Area, I’d like to revisit the great e-Nable community, which comes together to provide 3D printed prosthetics for hand and finger amputees. The e-Nable community includes many things; a collection of open source hand and finger designs accompanied by an international team of volunteers which include engineers, teachers, 3D printers, designers and of course receivers. Once someone in need of hand reaches out to the community, they can find someone nearby with a 3D printer and assistance for fit and assembly. There is constant growth with the core of providing affordable prosthetics; there are events, forums, and the designs are constantly being discussed and modified on its Google+ community.

When e-Nable first started, it was with a handful of people and designs. There are now more than 5000 volunteers, and the open source design categories have now grown to 9 on the website including hand, wrist, and partial hand prosthesis, with numerous variations of each. I’d like to spotlight the ‘Raptor Hand,’ a great complete hand prosthetic design which was made in mind for ease of fabrication.

Once the Raptor design is selected as the design of choice, it is accompanied by the Handomatic web application which allows a user to input hand measurements to create custom files for 3D printing the final product. The e-Nable site provides users with a list of materials needed and links for where to get them, as well as a diagram of parts, instructions for printing, and the great instructional video below:

The site also provides a helpful diagram of how all the parts fit together:

Raptor Hand Parts - Exploded View


Raptor photo source

Above Knee


This post is to highlight a product which is simple, beautiful, and readily available for the general public. While we often get caught up in the glitz of newer technology, the reality is that with government rules and regulations, it is often a significant amount of time before end users have access to many newer products. If you are an amputee, for example, UNYQ has provided an immediate solution for the minimal shape and aesthetics of current prosthetics.

To lose a limb not only has high physical, but also psychological cost. Beyond the physical healing of an amputated limb are also everyday questions and glances as a reminder to the injury. UNYQ has designed numerous customized prosthetic covers to add style and dignity beyond the functionality of a lower extremity prosthesis. Customers simply go to the site, take measurements and photos of their unaffected leg, and provide some information about their current prosthesis. One of the great attributes of UNYQ is that it provides prosthetics covers for both below knee and above knee amputees.

Once the measurements are completed and design is chosen, the prosthetics covers are printed using ABS (Acrylonitrile butadiene styrene), a type of plastic material used for 3D printing. The beauty of the designs really is stunning; there are many to choose from, and the themes range from camouflage to runway with the additional option to design your own. For someone dealing with loss of limb followed by essentially a peg prosthetic replacement, these covers recover some of the physical dignity and beauty that may feel lost with the injury. One can wear jeans and fitted clothing and regain some of the symmetry lost with the amputation, or reveal the design when wearing shorts or shorter clothing.

The other great attribute of UNYQ is the relatively low cost; it can be partially reimbursable by insurance. Please visit the site for more details and to brows the designs and personal stories on the website. There are options for men, women, and children.

Above Knee



3D printing is truly changing healthcare, allowing us to print everything from hearts to skulls to exoskeletons to hands. This revolution has paved the way for making replacement limbs for amputees financially accessible. In England, a young roboticist has made it his mission to begin a project to provide a low cost, open source 3D design kit for those with missing hands. Through crowdfunding, Joel Gibbard of Open Bionics was able to create a low cost robotic hand kit, including designs for both a robotic myoelectric hand and a prosthetic hand.

The robotic hand is titled the Adams Hand, using electric motors to replace muscles and steel cables to replace tendons. Movement of the intact muscles of the forearm and wrist enable synergistic movement of the device, meaning that an action such as bending the wrist would engage the bending of the 3D fingers and hand. With grabbing an item, the fingers stop once there is an object impeding their movement. Thus, the hand is able to master the task of grasping a fragile, uneven object such as an egg.

The project is geared both toward amputees and researchers for use in advancing the field of robotics.

A DIY kit includes Adams Hand, Servo, Wrist (with generic connector), wire tendon, mounting screws, servo horn, and instruction manual.  A price is not yet set. Please see the video below.

As technology and the 3D printing boom in healthcare moves ahead, it’s inspiring to see that some are still thinking of people that may not have access to all the great healthcare opportunities that come with more resources.

The age of robotics has created a new kind of athlete, and the possibilities are quite amazing. 2016 will mark the first Cybathlon, to be held in Switzerland. This will be a competition for parathletes, called “pilots,” using robot-assisted technology. The competition is an Olympics-style event, featuring six different competitions, or “disciplines.” Each discipline features pilots with a specific category of injury using an appropriate device. In this competition, both the pilots and robotics companies are allowed the opportunity to win a prize. This competition is not only a victory for the advancement of robotics beyond basic function, but more importantly for athletes with life altering injuries such as amputations and spinal cord injuries.

The first competition will is an “Arms Prosthetic Race,” which features two events. Those with amputation of the arms using upper body bionic prosthetics to complete a two hand course using a loop around a wire, and a “SHAP course ADL” which is an upper body obstacle course requiring pilots to perform a series of tasks, grasping different kinds of objects in order to progress to the next.

The second discipline is a BCI (brain computer interface) race, in which participants mentally race avatars through a variety of obstacle courses. This discipline is for those with spinal cord injury at neck level, which has left them paralyzed from the neck down.

The discipline close to heart, however, is the “Powered Exoskeleton Race.” Did we ever think we would see a day when athletes with spinal cord injuries leaving their lower body without motor control would run in an Olympic-style event? This discipline will feature an obstacle course including stairs, ramps, slopes, narrow beam and others, ending in a final sprint. Wow.

For those with spinal cord injuries leaving their trunk and upper body motor control intact, Discipline three features an FES (Functional Electrical Stimulation) bike race. An FES bike assists lower body movement while the trunk and arms work to help control the bike around a race course.

A Leg Prosthetics Race and Powered Wheelchair Race comprise two other disciplines for those with lower body injuries.