3D PRINTING PROSTHETIC: NEW ERA OF MEDICAL SCIENCE
John Nhial was barely a teenager when he was grabbed by a Sudanese guerrilla army and forced to become a child soldier. He was made to endure weeks of walking with so little food and water that some of his fellow captives died. Four more were killed one night in a wild-animal attack. Then the boys were given military training that involved “running up to ten kilometres in the heat and hiding” before being given guns and sent to fight “the Arabs”.
He spent four years fighting, bombed from the skies and blasting away on guns almost too heavy to hold against an enemy sometimes less than a kilometre away. “I think, ‘If I killed that one it’s a human being like me,’ but you are forced,” he said. One day the inevitable happened: Nhial (not his real name) was injured, treading on a mine while on early-morning patrol with two other soldiers in a patch of Upper Nile state surrounded by their enemies.
“I stepped on it and it exploded,” he recalled. “It threw me up and down again – and then I was looking around for my foot. I tried to look for my leg and found that there was no foot. When I saw there’s no foot I feel shock. I was really confused. If I was not with the two others I would kill myself because I thought there was no use for me now, so I decide to die.”
His comrades carried him back to base camp, but there was hardly any medical care there. It took 25 days before he received proper treatment, during which time he developed tetanus on one side of his body. Finally Nhial was put on a flight to the Kenyan border, his life saved when he was handed over to a Red Cross health team. Now, a decade later, he lives in a Juba refugee camp, having suffered further troubles in the whirlwind of conflict that has engulfed the struggling new nation of South Sudan.
During one outbreak of violence he was rounded up with other Nuer – the country’s second-largest ethnic group – and taken to an army barracks. His life was only spared when he was dismissed as “useless” because of his disability. Today he plays wheelchair basketball for his country, although he relies on a prosthetic lower leg to struggle his way round the muddy, sprawling camp that entails long walks to reach the most basic services. It can be difficult to get to training. But at least his hands are free to carry things such as food and water, unlike those on crutches.
Mary Lam (not her real name), 34, who caught polio as a child and today works as a restaurant supervisor in the capital, Juba, expl
ained what it was like growing up reliant on bamboo sticks to haul herself around with a bad leg. She would get up much earlier than her siblings, since it took an hour to get to the classroom and they could rush there much quicker. “It was hard to go with my exercise book to school unless I tie it on my back like a baby,” she said. And it limited her use of her arms too. “When two hands are using the bamboos you are not able to do domestic work in the house.”
Stories of lives devastated by conflict or disease are all too common across low-income countries. Lack of an arm or leg can be tough anywhere, but for people in poorer parts of the planet, with so much less support and more rickety infrastructure, it is especially challenging. Some are victims of conflict, others were born with congenital conditions. Many more are injured on roads, the casualty toll soaring in low-income nations even as it plummets in wealthier ones. Every minute, 20 people are seriously injured worldwide in road crashes. In Kenya, half the patients on surgical wards have road injuries.
The World Health Organization (WHO) estimates there are about 30 million people like Nhial and Lam who require prosthetic limbs, braces or other mobility devices. These can be simple to make and inexpensive. As one veteran prosthetist told me, his specialism is among the most instantly gratifying areas of medicine. “A patient comes in on Monday on crutches that leave them unable to carry anything. By Wednesday they are walking on a new leg and on Friday they leave with their life transformed.”
Yet more than eight in ten of those people needing mobility devices do not have them. They take a lot of work and expertise to produce and fit, and the WHO says there is a shortage of 40,000 trained prosthetists in poorer countries. There is also the time and cost to patients, who may have to travel long distances for treatment that can take five days – to assess need, produce a prosthesis and fit it to the residual limb. The result is that unglamorous items such as braces and artificial limbs are among the most-needed devices to assist lives. Yet, as in so many other areas, technology may be hurtling to the rescue, this time in the shape of 3D printing.
Slowly but surely, 3D printing – otherwise known as additive manufacturing – has been revolutionising aspects of medicine since the start of the century, just as it has impacted on so many other industries, from cars to clothing. Perhaps this is not surprising, given that its key benefit is to enable rapid and cost-efficient creation of bespoke products. There are, after all, few commercial products that need to suit a wider variety of shapes and sizes than medical devices made for human beings.
Experts have developed 3D-printed skin for burn victims, airway splints for infants, facial reconstruction parts for cancer patients, orthopaedic implants for pensioners. The fast-developing technology has churned out more than 60 million customised hearing-aid shells and ear moulds, while it is daily producing thousands of dental crowns and bridges from digital scans of teeth, disrupting the traditional wax modelling methods used for centuries. Jaw surgeries and knee replacement operations are also routinely carried out using surgical guides printed on the machines.
So it is unsurprising the technology began to stir interest in the field of prosthetics – even if sometimes by accident. Ivan Owen is an American artist who likes to make “weird, nerdy gadgets” for use in puppetry and budget horror movies. In 2011 he created a simple metal mechanical hand for a steampunk convention, the spiky fingers pulled by loops through his own. He posted a video that – as is the way in our interconnected world – was seen by a carpenter in South Africa who had just lost four fingers in a circular saw accident. They began discussing plans for a prototype prosthetic hand, and soon that came to the attention of the mother of a five-year-old boy called Liam, born without fingers on his right hand.
She wanted a tiny version of their hand. But Owen realised the child would rapidly grow out of anything they made, so he looked at the idea of using 3D printing. “If we could develop a design that was printable, it would be possible to rescale and reprint that design as Liam grew, essentially making it possible for his device to grow with him,” he said. So the artist persuaded a printer manufacturer to donate two machines and developed what has been claimed to be the first 3D-printed mechanical hand. And crucially, rather than patent this work, Owen published the files as open source for anybody to access, allowing others to collaborate, to use and improve the designs.
This has grown into Enabling the Future, a community with 7,000 members in dozens of countries and access to 2,000 printers, who help make arms and hands for those in need. One school student in California even printed a new hand for a local teacher. Often they are aimed at children, since many dislike the weight, look and hassle of modern prosthetics, which can involve inserting the arm in a silicone sleeve and using straps across the back to hold the device in place. These body-powered hands cost thousands of pounds, yet must be replaced every couple of years as a child grows. The 3D-printed versions cost about £40, come in any colour and look like a cheery toy, so are often more appealing despite being less sophisticated.
Jorge Zuniga, a research scientist in the Biomechanics Research Building at the University of Nebraska in Omaha, heard about this project on his car radio. He was only half-listening, but arriving home he started playing baseball with his four-year-old son and observed how important the grabbing of an object was to his own child’s development. He spent the next month carefully building a prosthetic model that mimicked the human hand, only for his work to be dismissed instantly by his son. “He told me children wanted a hand that looked like a robot.”
From this conversation and the open-source designs available emerged Cyborg Beast, a project being heavily backed by his department to develop futuristic-looking, low-cost prosthetic hands. “You can do anything with 3D printing,” said Zuniga, who now heads a seven-strong team. “We believe it will revolutionise the prosthetics field. It will lower the costs worldwide and gives engineers, patients and doctors the chance to modify prosthetic hands as they want. And they can be any colour.”
When I told Zuniga slightly hesitantly that his design looked like a toy, he was delighted. “That’s great – we want children to see it as a toy,” he said. “This is a transitional device. Many children do not like prosthetics, however good they are these days, because they might have a hook for a hand and the harness needs help to put on, which children dislike. So this is to bridge the gap, helping them get used to the idea as they grow up.
“We have even had a child missing a shoulder. So we developed a device that weighs the same as the missing arm. This meant he not only got a new arm that helped daily life but it also improved his posture and balance, therefore was much better for his spine. This sort of thing can be done much easier with 3D technology. But of course the difference between a toy and a prosthetic arm is that you need professional involvement to enhance use of the devices and ensure they are fitting properly.”
It is remarkable that people who do not even own a printer can obtain a functional child’s hand for the price of a theatre ticket within 24 hours. Zuniga says at least 500 Cyborg Beasts are in use worldwide, and the design has been downloaded almost 50,000 times. He has taken it to his native Chile, where he runs a paediatric orthopaedic 3D-printing laboratory, and has had recent requests for the plans from Nigeria. “My concern at this stage is that some of the materials can melt in higher temperatures. It is not working well there yet, but this sort of prosthetic has huge potential to be used with better materials in the developing world. We are still in the infancy stage at this moment.”
Another place that has experimented with this technology is in the cruel, forgotten war cursing the Nuba mountains of Sudan, where an amazing American named Tom Catena has been working as the only permanent doctor for half a million people around his Mother of Mercy Hospital. Fuelled by his religious faith, for almost a decade this brave medic has ignored bombings, lack of electricity and water shortages to do everything from delivering babies to amputating limbs.
“It’s demoralising for us to amputate an arm knowing that there is no good solution,” Catena told me by email. “We have many arm amputees – both above and below the elbow as a result of the war here and general lack of medical care. This in an agricultural society, where nearly everyone is a subsistence farmer. If one is missing an arm, he is not very functional in this society. They become totally dependent on the family and they have a difficult time getting married (also very important in this society).”
The idea of using 3D printing to help arose when Mick Ebeling, an American film producer and philanthropist, learned about this work at the same time as he was hearing about the emerging work on low-cost prosthetic hands. Searching for information on Catena, Ebeling read about one of his patients: Daniel Omar, a 12-year-old boy who had wrapped his arms around a tree to protect himself during an aerial attack. His face and body were protected when a bomb exploded nearby – but both the boy’s arms were blown off.
Ebeling travelled out with printers and, working with hospital staff, fitted about a dozen people with new arms. “Unfortunately, as time went on, none of the amputees were using the prostheses as they felt they were too cumbersome,” said Catena. The doctor concluded that “the 3D model was good, fairly easy to make and inexpensive… although it hasn’t worked out so well here, perhaps with some tweaking, the 3D printers can be of great use for arm amputees.”
