A game-changer in prosthetics has been introduced to the world, and for the first time, amputees are regaining sensation through an electrical signal from their prosthetic arm. Max Ortiz-Catalan, a professor of bionics, explains the process of implanting these mind-controlled bionic arms through direct skeletal attachment. The researcher takes us through every step of this groundbreaking advancement in bionic medicine, from surgically implanting electrodes to fitting the prosthesis and training for everyday use.
Director: Lisandro Perez-Rey
Editor: Jordan Calig
Expert: Prof. Max Ortiz Catalan
Line Producer: Joseph Buscemi
Associate Producer: Kameryn Hamilton
Production Manager: D. Eric Martinez
Production Coordinator: Fernando Davila
Post Production Supervisor: Alexa Deutsch
Post Production Coordinator: Ian Bryant
Supervising Editor: Doug Larsen
Assistant Editor: Justin Symonds
Director: Lisandro Perez-Rey
Editor: Jordan Calig
Expert: Prof. Max Ortiz Catalan
Line Producer: Joseph Buscemi
Associate Producer: Kameryn Hamilton
Production Manager: D. Eric Martinez
Production Coordinator: Fernando Davila
Post Production Supervisor: Alexa Deutsch
Post Production Coordinator: Ian Bryant
Supervising Editor: Doug Larsen
Assistant Editor: Justin Symonds
Category
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TechTranscript
00:00 you're looking at a game changer in prosthetics.
00:02 - The only one today using electrodes implanted
00:05 in the nerves and to have sensation.
00:07 - The developer of this bionic system
00:08 is speaking to us from Ukraine,
00:10 where war has led to a crisis.
00:12 - There is more than 15,000 people
00:14 with amputations in the country.
00:16 - Let's walk through every step needed
00:18 to implant his bionic arm into a patient.
00:21 - Bionic basically means that it's a combination
00:23 between biology and electronics.
00:25 - But traditionally, prosthetic arms are a pretty low-fi.
00:28 Some are purely aesthetic, made in silicone,
00:30 but not functional.
00:31 Then there are functional mechanical ones,
00:33 powered by a wire and a patient's own movements.
00:36 - You can think about a claw or a hook
00:38 that can open and close,
00:39 and it has a system of gears like brakes for your bicycle.
00:43 - Then you have fancy electric prostheses,
00:45 where a patient can control the fingers independently
00:48 via electrodes placed on the surface of the skin.
00:51 But how do you keep the arm in place?
00:53 - This is normally done with a socket,
00:55 something that is on your skin, putting a lot of pressure.
00:58 - It's uncomfortable and heavy,
00:59 so that's why the first step
01:00 in installing Dr. Ortiz-Catalan's bionic arm
01:03 is osseointegration,
01:04 or implanting a titanium structure directly to the skeleton.
01:08 - Osseointegration made a big splash in the medical field.
01:12 The first application were dental implants.
01:14 - Eventually, scientists applied this to prosthetics
01:16 after discovering in the '50s
01:18 that if you attach titanium inside bone,
01:20 the bone cells can grow directly on the titanium,
01:23 making a very strong attachment to the residual limb.
01:26 - Say you have a transhumeral amputation above the elbow.
01:29 The surgeon will place a titanium implant
01:31 that looks like a screw inside the center of the bone,
01:35 and you leave it there for a few months.
01:36 In that period, the bone cells grow
01:38 around the titanium implant,
01:40 and then you place a portion of the implant
01:43 that comes out through the skin,
01:45 and that's where you're gonna connect your prosthesis.
01:47 - Implanting into a residual limb
01:49 that has been amputated below the elbow
01:51 has its own challenges,
01:52 because there are two smaller bones,
01:54 the radius and the ulna,
01:55 and they move independently from each other.
01:57 - So they will move like this,
01:58 they will move like this,
02:00 and they will also move in their own axis.
02:02 So we develop an artificial joint
02:04 that allows for those movements to take place
02:07 while preserving a natural orbit for the movement.
02:10 - Now, the next step is to surgically implant
02:12 the electrodes inside the body.
02:14 - We will place electrodes in the muscles
02:17 and the nerves around the residual limb.
02:20 Electrodes on the surface of the skin
02:21 are susceptible to electromagnetic interference.
02:24 Stuff all around us, like tools or computers,
02:27 can create noise interference,
02:28 radiating to the electrodes
02:30 if they're merely sitting on the surface of the skin.
02:32 This will cause the prosthetic to become uncontrollable.
02:34 Even just moving your arm around
02:36 can throw off a conventional sensor.
02:38 - If it lifts a little bit,
02:39 it generates this, what's called a motion artifact.
02:41 If you move too fast, if you sweat,
02:43 the prosthesis become less controllable.
02:45 - With electrodes implanted directly inside muscles
02:48 on nerves, you don't have any of those problems.
02:50 - If you have an amputation where the hand is gone,
02:52 you have many muscles here
02:54 that help you to control the fingers of the hand.
02:56 So there's a lot of sources
02:57 that you can use to drive the prosthesis.
02:59 - But in the case of an amputation above the elbow,
03:02 you don't have as much to work with.
03:03 So the team has to get creative
03:05 and rejigger the body's original biological wiring.
03:08 - You have the biceps, and the biceps has two heads.
03:11 So it's not enough information
03:13 that we can extract from the muscles
03:14 to drive all the missing joints.
03:16 So a solution for that is you can take a nerve
03:19 that used to go to the hand,
03:20 and then you transfer it into one head of the biceps.
03:23 So then when the patient thinks about closing the hand,
03:25 this part of the muscle will contract, the short head.
03:28 - There are three big nerves in the arm,
03:29 the radial, the ulnar, and the median,
03:31 which allows you to control these three fingers.
03:33 Basically, a nerve is a collection of axons
03:36 which are bundled into fascicles.
03:37 - So if you think about my fingers
03:39 as the bundles of the nerve,
03:40 what you can do is split them.
03:42 You take one of those bundles
03:43 to connect with that muscle that is available there.
03:45 And then for the other ones,
03:46 we can borrow a piece of muscle from the legs.
03:49 It's called a free muscle graft.
03:51 And then we transfer that to the arm
03:53 to connect to one of these fascicles.
03:55 - Next, you insert a metal electrode into the muscle
03:58 and connect that to the connector
04:00 inside the titanium implants.
04:01 - So it has a wire,
04:03 and that wire is covered by materials that are biocompatible,
04:06 meaning that they're well taken by the body.
04:08 - The signals that come from your brain
04:09 to control your limbs travel through nerves,
04:12 but these organic signals are relatively weak,
04:14 about 10,000 times smaller than the strength
04:16 of the signals generated by these new electric plugs.
04:20 So in a way, the implanted electrodes
04:22 use the muscle like a loudspeaker,
04:23 amplifying the signals from the brain to the muscles
04:26 and to the prosthesis.
04:27 - The implantable part has no batteries.
04:30 All the power happens in the prosthesis.
04:32 You can think about it as a USB port into the nervous system.
04:36 - The next step involves training the AI
04:38 in the Bionic Hand CPU
04:39 to understand what the signals from the brain mean.
04:42 - The way we control our limbs
04:43 is by electric signals coming down
04:45 through the nerves to the muscles,
04:47 and these come in the form of electric impulses.
04:50 Those signals are captured
04:51 by the electronics of the prosthesis,
04:53 so they travel down to the prosthesis
04:54 where there is the brain of the prosthesis,
04:56 understands what those signals are.
04:58 - But that CPU in the prosthesis
05:00 doesn't automatically know
05:01 what those patterns of activation mean.
05:03 The AI needs to be trained.
05:04 - What we do is we tell the patient,
05:06 "Try to close your hand," and then we record signals.
05:09 And then we say, "Try to open your hand,"
05:10 and we record the signals.
05:11 - And then the team labels that action for the AI,
05:14 translating neural signals from the brain
05:16 into code that is now understood
05:18 by the tiny computer in the prosthetic arm,
05:21 which then engages its robotic motors
05:23 to move in specific ways.
05:25 The next step involves training the patient using software.
05:28 - This was actually the first time
05:29 we saw the patient after the surgery.
05:31 We connected it to a virtual reality system.
05:33 - Those two cables coming out of the implants
05:35 are sending signals wirelessly to the computer
05:37 where they are interpreted
05:39 and used to control a virtual limb.
05:41 This trains the muscles
05:42 and makes the signals more distinct and reliable
05:44 in preparation for when the patient gets their bionic limb.
05:47 But this training also addresses another challenge
05:50 that arises from amputation.
05:52 - After you have an amputation,
05:53 there's pain that remains
05:55 from something called phantom limb pain.
05:57 - Which is caused by the brain getting confused
05:59 and imagining that the missing limb is frozen
06:01 or twisting in awkward ways.
06:03 - So I developed some technologies
06:05 to treat phantom limb pain.
06:06 We coupled those with virtual augmented reality
06:09 so the patient can engage the same neural resources
06:12 that were used to control the hand.
06:14 This helps them reduce their pain.
06:15 - This training is useful in fine tuning the algorithms
06:18 that will drive the robotic motors.
06:19 But working in the virtual world is one thing.
06:22 Without their bionic arm attached,
06:23 patients will do relatively well because there's no load.
06:26 So the final step involves fitting the prosthesis
06:30 and testing in the real world.
06:32 Patients come into the lab, put on their bionic arm,
06:34 and perform daily tasks like packing a suitcase
06:37 or picking up small objects.
06:39 - These are tasks that can tell you a little bit
06:41 about the function the patient has with the prosthesis.
06:44 - The team then makes adjustments and runs further tests
06:47 that evaluate and help improve
06:49 one of the most jaw-dropping features of the prosthetic,
06:52 its ability to feel objects in its grasp.
06:55 - When the prosthesis make contacts with the object,
06:58 there are sensors in the fingertips.
07:00 And then the brain of the prosthesis
07:01 has also a neurostimulator,
07:04 which delivers electrical pulses to the nerves.
07:06 - And because the brain receives this data from a nerve
07:09 that used to be connected to the biological limb,
07:12 it will interpret it as coming from the bionic hand.
07:15 - If I have a biological receptor in my index finger
07:18 that has a nerve that goes all the way up to my brain,
07:20 if I put an electrode along that nerve,
07:23 it doesn't matter where I stimulate,
07:25 the brain will create a sensation
07:26 as coming from the fingertip.
07:28 It's an automatic sensation that rises in consciousness.
07:31 - The bionic hand uses sensors in its thumb and index finger
07:34 to send an electrical signal through the prosthetic
07:37 and then along the original severed nerves
07:39 straight to the brain.
07:40 But the information from the fingertips is not as nuanced
07:43 as what a biological fingertip feels.
07:45 - For us, we have hundreds of sensors that travel
07:48 in hundreds of neurons.
07:50 Today, we don't have that resolution
07:52 at the neural interface.
07:53 - We're still a long way off from the type of sensation
07:55 seen in the artificial limbs in "Star Wars."
07:58 This hand only provides rough sensations,
08:00 but they're still useful because now a patient can feel
08:03 when there's an object in their hand
08:04 and if that object is slipping away.
08:06 But what about batteries?
08:08 They have to power the CPU and the motors
08:09 that drive the prosthesis, right?
08:11 - You can have interchangeable batteries
08:13 and whenever the prosthesis run out of battery,
08:15 they just switch it.
08:16 A battery will normally last a full day.
08:18 It's very much like our phones.
08:19 Everything is self-contained.
08:21 - So the days of patients carrying heavy backpacks
08:23 full of computers or bulky batteries are gone.
08:25 These days, Dr. Ortiz-Catalan really only sees patients
08:28 a couple times a year, when something breaks
08:30 or if he needs to fine-tune anything.
08:32 But these high-end bionic hands can come with a price tag
08:35 of over $10,000.
08:37 - But hopefully, like any other technology,
08:39 more is available, the less the cost will be.
08:42 We created a human-machine interface,
08:44 which means we can connect the prosthesis
08:46 or we can connect to your steering wheel of your car
08:49 and you can drive it by thinking about movement of the wrist.
08:51 You can integrate it to whatever your imagination wants.
08:54 - Cool, so can we make humans stronger, cyborg-style?
08:58 - There will be companies that think
09:00 about human augmentation, making a human jump higher,
09:03 run faster, carry higher loads.
09:05 You can have one prosthesis that's much stronger
09:08 than a human hand, but you cannot have a prosthesis
09:11 that is as dexterous as a human hand.
09:12 That's something that we haven't achieved
09:14 from the robotic side.
09:16 Personally, I got involved in prosthetic devices
09:18 because I wanted to solve problems.
09:21 And I'm in the business of bionic medicine.
09:23 There's so many problems out there that have not been solved
09:26 when it comes to disabilities,
09:28 that I feel that it's more important that we focus on that.
09:31 (upbeat music)