Rapid innovations in 3D printing are not only taking the medical world by storm but redesigning the possibilities for ultra-cheap custom prosthesis and adaptive devices. So much so, that gone are the days of basic hand prosthesis in a standard design with limited functionality. The speed and nominal cost at which custom components can be produced using 3D printing have fast-tracked the advent of reliable, durable, realistically shaped, functional prosthetic devices all over the world.
South Africa has been at the forefront of this new order of hand prosthesis. Motivated by need to offer a better solution at a lower cost, mechanically operated hand prosthesis for the public health sector and simply for those in need but without means, three separate innovative designs have taken the industry to a new level and put hope and cost savings back into the hands of the people they’re trying to help.
For amputees and those born with congenital abnormalities such as Symbrachydactyly, a condition typically characterised by the lack of finger bones or fingers altogether, the arrival of more affordable, more functional hand prosthesis that can be produced quickly, opens the door to leading a more fulfilling life. That is exactly the premise for Richard van As, a local pioneer in the mechanical hand space and founder of Robohand – a world first in customisable, anatomically driven mechanical hands and fingers produced using low cost 3D printing technology.
A helping hand
Van As started exploring the possibilities for prosthesis design after losing several fingers in a carpentry accident in 2012. His research led him to collaborate with Ivan Owen, a puppet maker from the US, and together they developed the prototype for Robohand. Van As understood the limitations of standard prosthesis first hand as his injury wasn’t suitable for what was available, nor did it give him back any of the functionality that he needed.
After creating the first aluminium hand using 3D printing, his work to help other limb different individuals spurred the prototyping of the Robofinger and Roboarm. All of the designs developed by Robohand use medical grade hardware and splinting material to ensure the safety of the wearer and the fingers and other components printed by 3D using a bio degradable plastic made out of corn starch which is both cheap and durable.
To date, Richard and his team have helped more than 500 children and adults take back some of their quality of life. Each Robohand is produced specifically for the wearer at a cost of R5,000 putting the prosthesis well within the reach of those who can afford it and subsidise those who can’t. Their motto: “enable one, enable many” is backed up by the fact that they’ve made their designs open source and available on an online platform that can be downloaded for free, allowing anyone to create their own basic Robohand.
Making the CUT
While van As has since produced Robobeast, his own 3D printer that is commercially available to subsidise those who can’t afford to purchase their prosthesis, other innovators in the space are working with the Centre for Rapid Prototyping and Manufacturing at the Central University of Technology (CUT) in Bloemfontein to produce their prototypes. As is the case with award winning Engineering Professor at UCT, Dr George Vicatos and MSc student Severin Tenim. The duo collaborated with CUT to develop the Tenim Hand, a low cost prosthetic that earned them the Cutting Edge award at the 2014 Popular Mechanics FutureTech event in Cape Town.
Described as a ‘mechanical prosthetic’ that uses a metal cord at the wrist to control the fingers and thumb’s grip and release function. Meaning that by pulling the cord, the fingers can be open, partially open or fully closed. The cord works together with a button in line with the fifth metacarpal – or little finger – that locks or releases the hand when the button is pressed. The thumb is attached by a swivel to rotate and move towards or away from the fingers.
What sets this device apart from other mechanical hands is that each individual finger can be moved separately from the others, as opposed to opening or closing the entire hand at the same time. According to Dr Vicatos, there is no other mechanical hand that is as close to the anatomical function of a human hand.
Before 3D printing, typical low cost hand prosthesis were either a hook or spilt finger prosthesis which are activated manually by movements in the wearers shoulder that moves a cable causing the hook or split finger to open to allow the wearer to hold something or pick up an object, for example. But in order for the wearer to continue to hold an object, the shoulder must continually activate the mechanism keeping the hand open.
As with all prosthesis, the patient has to learn how to manipulate the device but wearing and manipulating it for long periods often results in muscle fatigue, irritation at the shoulder and axilla, or armpit, and can lead to skeletal and neurological problems. But for the wearer, the ability to close the hand is the most important aspect of functionality. The Tenim Hand is activated by the same principle as the standard hand prosthesis so the patient doesn’t have to learn new techniques, but it boasts a more efficient actuation, usability and less discomfort.
The Tenim hand also allows wearers some of the fine motor skills that standard prosthesis can’t, such as the ability to pinch, grasp, and even hold delicate objects without breaking them. And because the prosthesis can lock in a closed position, it will continue to hold an object without having to constantly activate the cable, allowing the shoulder to relax.
Dr Vicatos credits using locally designed and manufactured parts instead of imported equivalents as key to producing an affordable prosthesis. The hand design is currently being assessed for efficiency and a provisional patent was filed in July 2014 in the UK. Once the prosthesis becomes commercially available, Dr Vicatos estimates they will cost R25,000 – a sum that is much more attractive to the public sector and medical aids than the R50,000 starting point for hand prosthesis using mechanical activation.
Another duo taking hand prosthesis one step further hail from the University of KwaZulu Natal (UKZN) is MSc graduate, Drew van der Riet, and his supervisor, Professor Riaan Stopforth. They recognised that sensory feedback is the biggest limitation of modern prosthetics and developed a modular device that operates on a bio-mechatronic system, incorporating mechanical engineering, electronics engineering, computer engineering and biology to produce a more human-like prosthetic – the Touch Hand II.
The hand consists of a mechanical exterior with an electronic interior allowing wearers to control the movement of the fingers by way of small electrode pads positioned on the amputee’s residual muscles. The hand uses Electromyography (EMG) signals produced by skeletal muscles in combination with bio-mechatronics, an interdisciplinary science that allows devices to interact with human muscle, skeleton and nervous systems, to give wearers back the sense of touch.
Wearing Touch Hand II will mean that amputees will not only benefit from improved functionality but can also sense vibration, temperature, texture (such as rough or smooth surfaces), and pressure – allowing them to hold delicate objects without breaking them.
Stopforth and van der Riet have established Touch Prosthetics, a company aiming to drive the field of prosthetics technology, making it more accessible to the general public through affordable, modular advanced prosthetics produced with 3D printing.
Having already won several awards and accolades for Touch Hand II, the team are leading the way for true robotics-based projects in South Africa and hope to change as many lives as possible in the process. According to van der Riet, by using 3D printing, and more affordable censors and components, Touch Prosthetics can restore an amputees hand function and sense of touch for just R10,000 in comparison to the cost of a standard hook prosthetic which costs between R10-R15,000.
Sensory prosthetics produced internationally can cost between R300,000 and R1 million but van der Riet explained that by leveraging a modular design, the advanced prosthetic is affordable because each additional feature can be sold separately, meaning that wearers can upgrade their hand as opposed to buying a new one. Giving wearers the ability to choose the amount of censors they want and can afford is another level in the customisation many are trying to offer wearers, but have not yet been able to achieve.
Currently, Touch Hand II is being tested by John Harris, an amputee for 20 years, who learnt to use the device in under an hour. Touch Prosthetics are using test results to develop the Touch Hand II further to generate interest from both the public and private sector, funding organisations and research bodies to help them bring the sense of touch to market.