The sore problem of prosthetic limbs

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, he set out to discover why — and to solve the problem with his team from the MIT Media Lab.

I was born and raised in Sierra Leone,

a small and very beautiful country

in West Africa,

a country rich both in physical resources

and creative talent.

However, Sierra Leone is infamous

for a decade-long rebel war in the '90s

when entire villages were burnt down.

An estimated 8,000 men, women and children

had their arms and legs amputated during this time.

As my family and I ran for safety

when I was about 12 from one of those attacks,

I resolved that I would do everything I could

to ensure that my own children

would not go through the
same experiences we had.

They would, in fact, be part of a Sierra Leone

where war and amputation

were no longer a strategy for gaining power.

As I watched people who I knew, loved ones,

recover from this devastation,

one thing that deeply troubled me

was that many of the amputees in the country

would not use their prostheses.

The reason, I would come to find out,

was that their prosthetic sockets

were painful because they did not fit well.

The prosthetic socket is the part

in which the amputee inserts their residual limb,

and which connects to the prosthetic ankle.

Even in the developed world,

it takes a period of three weeks to often years

for a patient to get a comfortable socket, if ever.

Prosthetists still use conventional processes

like molding and casting

to create single-material prosthetic sockets.

Such sockets often leave intolerable amounts

of pressure on the limbs of the patient,

leaving them with pressure sores and blisters.

It does not matter

how powerful your prosthetic ankle is.

If your prosthetic socket is uncomfortable,

you will not use your leg,

and that is just simply unacceptable in our age.

So one day, when I met professor Hugh Herr

about two and a half years ago,

and he asked me if I knew
how to solve this problem,

I said, "No, not yet,

but I would love to figure it out."

And so, for my Ph.D. at the MIT Media Lab,

I designed custom prosthetic sockets

quickly and cheaply

that are more comfortable

than conventional prostheses.

I used magnetic resonance imaging

to capture the actual shape of the patient's anatomy,

then use finite element modeling to better predict

the internal stresses and strains

on the normal forces,

and then create a prosthetic socket for manufacture.

We use a 3D printer to create

a multi-material prosthetic socket

which relieves pressure where needed

on the anatomy of the patient.

In short, we're using data

to make novel sockets quickly and cheaply.

In a recent trial we just wrapped up

at the Media Lab,

one of our patients, a U.S. veteran

who has been an amputee for about 20 years

and worn dozens of legs,

said of one of our printed parts,

"It's so soft, it's like walking on pillows,

and it's effing sexy."

(Laughter)

Disability in our age

should not prevent anyone

from living meaningful lives.

My hope and desire is that the tools and processes

we develop in our research group

can be used to bring highly functional prostheses

to those who need them.

For me, a place to begin healing the souls

of those affected by war and disease

is by creating comfortable and affordable interfaces

for their bodies.

Whether it's in Sierra Leone or in Boston,

I hope this not only restores

but indeed transforms their
sense of human potential.

Thank you very much.

(Applause)