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TED2014

David Sengeh: The sore problem of prosthetic limbs

March 17, 2014

What drove David Sengeh to create a more comfortable prosthetic limb? He grew up in Sierra Leone, and too many of the people he loves are missing limbs after the brutal civil war there. When he noticed that people who had prosthetics weren’t actually wearing them, the TED Fellow set out to discover why — and to solve the problem with his team from the MIT Media Lab.

David Sengeh - Biomechatronics engineer
Even the most advanced prosthetic isn't useful if it's hard to wear. This observation guides TED Fellow David Sengeh's work at the Biomechatronics group in the MIT Media Lab. Full bio

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Double-click the English subtitles below to play the video.
I was born and raised in Sierra Leone,
00:12
a small and very beautiful country
00:16
in West Africa,
00:19
a country rich both in physical resources
00:20
and creative talent.
00:23
However, Sierra Leone is infamous
00:26
for a decade-long rebel war in the '90s
00:28
when entire villages were burnt down.
00:30
An estimated 8,000 men, women and children
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had their arms and legs amputated during this time.
00:37
As my family and I ran for safety
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when I was about 12 from one of those attacks,
00:45
I resolved that I would do everything I could
00:47
to ensure that my own children
00:51
would not go through the
same experiences we had.
00:53
They would, in fact, be part of a Sierra Leone
00:56
where war and amputation
00:59
were no longer a strategy for gaining power.
01:01
As I watched people who I knew, loved ones,
01:06
recover from this devastation,
01:10
one thing that deeply troubled me
01:12
was that many of the amputees in the country
01:14
would not use their prostheses.
01:17
The reason, I would come to find out,
01:19
was that their prosthetic sockets
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were painful because they did not fit well.
01:23
The prosthetic socket is the part
01:29
in which the amputee inserts their residual limb,
01:31
and which connects to the prosthetic ankle.
01:34
Even in the developed world,
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it takes a period of three weeks to often years
01:38
for a patient to get a comfortable socket, if ever.
01:42
Prosthetists still use conventional processes
01:46
like molding and casting
01:49
to create single-material prosthetic sockets.
01:51
Such sockets often leave intolerable amounts
01:55
of pressure on the limbs of the patient,
01:58
leaving them with pressure sores and blisters.
02:01
It does not matter
02:05
how powerful your prosthetic ankle is.
02:07
If your prosthetic socket is uncomfortable,
02:10
you will not use your leg,
02:13
and that is just simply unacceptable in our age.
02:15
So one day, when I met professor Hugh Herr
02:18
about two and a half years ago,
02:21
and he asked me if I knew
how to solve this problem,
02:22
I said, "No, not yet,
02:25
but I would love to figure it out."
02:27
And so, for my Ph.D. at the MIT Media Lab,
02:30
I designed custom prosthetic sockets
02:33
quickly and cheaply
02:36
that are more comfortable
02:39
than conventional prostheses.
02:41
I used magnetic resonance imaging
02:44
to capture the actual shape of the patient's anatomy,
02:46
then use finite element modeling to better predict
02:50
the internal stresses and strains
02:53
on the normal forces,
02:55
and then create a prosthetic socket for manufacture.
02:57
We use a 3D printer to create
03:01
a multi-material prosthetic socket
03:05
which relieves pressure where needed
03:09
on the anatomy of the patient.
03:11
In short, we're using data
03:15
to make novel sockets quickly and cheaply.
03:17
In a recent trial we just wrapped up
03:21
at the Media Lab,
03:23
one of our patients, a U.S. veteran
03:25
who has been an amputee for about 20 years
03:27
and worn dozens of legs,
03:30
said of one of our printed parts,
03:33
"It's so soft, it's like walking on pillows,
03:37
and it's effing sexy."
03:41
(Laughter)
03:44
Disability in our age
03:48
should not prevent anyone
03:51
from living meaningful lives.
03:52
My hope and desire is that the tools and processes
03:55
we develop in our research group
03:59
can be used to bring highly functional prostheses
04:01
to those who need them.
04:04
For me, a place to begin healing the souls
04:06
of those affected by war and disease
04:11
is by creating comfortable and affordable interfaces
04:15
for their bodies.
04:19
Whether it's in Sierra Leone or in Boston,
04:21
I hope this not only restores
04:24
but indeed transforms their
sense of human potential.
04:28
Thank you very much.
04:31
(Applause)
04:34

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David Sengeh - Biomechatronics engineer
Even the most advanced prosthetic isn't useful if it's hard to wear. This observation guides TED Fellow David Sengeh's work at the Biomechatronics group in the MIT Media Lab.

Why you should listen

David Sengeh was born and raised in Sierra Leone, where more than 8,000 men, women and children had limbs amputated during a brutal civil war. He noticed that many people there opted not to wear a prosthesis because proper fit is such an issue.

Sengeh has pioneered a new system for creating prosthetic sockets, which fit a prothesis onto a patient's residual limb. Using MRI to map the shape, computer-assisted design to predict internal strains and 3D printing to allow for different materials to be used in different places, Sengeh is creating sockets that are far more comfortable than traditional models. These sockets can be produced cheaply and quickly, making them far more likely to help amputees across the globe. 

Sengeh was named one of Forbes' 30 under 30 in Technology in 2014, and in April 2014, Sengeh won the $15,000 "Cure it!" Lemelson-MIT National Collegiate Student Prize.

The original video is available on TED.com
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