The art of rewiring – Jennifer Ernst on innovative amputation medicine

00:00:00: So if you perform TMR, the overlying skin, the sensory nerves will find the overlying skin.

00:00:07: And then, yes indeed, you have when you shower and water is running down your chest, you feel parts of your hand according to the nerve.

00:00:16: This is quite spooky.

00:00:26: Welcome to a taste of Bionics, the podcast where we explore how technology and biology merge.

00:00:36: My name is Ranga Yogeshwar.

00:00:39: Just imagine losing an arm or a leg and then, yes, later, regaining not only movement but feeling the sense of touch, weight, balance that tells your brain.

00:00:55: This is me again.

00:00:58: My guest today is Jennifer Ernst.

00:01:01: She heads the Innovation Amputation Medicine Group at the Hanover Medical School, and her work is redefining how we treat limb loss, not as a mechanical replacement problem, but as a dialogue between the nervous system and technology.

00:01:21: Jennifer, welcome to a taste of bionics.

00:01:25: Thank you very much and thank you very much for this brilliant introduction.

00:01:29: I hope it is brilliant.

00:01:31: We will see that there is even much more brilliance to come.

00:01:35: First of all, just a very personal question, Jennifer.

00:01:38: What made you enter into this field?

00:01:41: Because very often what I found out is people have their story which led them to do what they're doing right now.

00:01:49: This is a good question.

00:01:50: I've been asked very often because amputation surgery is not really like the want to go field for many surgeons.

00:01:59: Actually, for many surgeons, it felt like failure.

00:02:02: So when all the reconstructive approaches failed, But already in college I was fascinated by nerves and when I studied neurobiology, how they communicate to each other, how they regenerate the possibilities of reading their commands and signals, fascinated me.

00:02:22: And then later on when I studied medicine and I started my residency, I treated so many.

00:02:31: trauma patients with devastating injuries.

00:02:34: And I could see that those people, yes, the injured people, they need more than just a single surgery slash operation.

00:02:43: They need somebody who's like their mentor or advocate for the whole circle of rehabilitation, what sometimes takes.

00:02:54: their whole life.

00:02:55: Yes, I mean they need to have somebody supporting them to cope with it and to struggle back to life and therefore I often feel very honored that with the surgery and the best possible way I can support them to rebuild their new whole life.

00:03:17: Well, if you look at the website of NIEFA, the Niedersächsisches Zentrum für Biomedizintechnik, You also speak about bionics.

00:03:27: Let me just quote for us.

00:03:28: Bionics means that we change the human being, the human biology through an additional surgical intervention in such a way that it can communicate with the available technology in the best possible way.

00:03:43: thus creating a completely new interface of the residual limb for the absorption of information.

00:03:51: Bionics thus combines biology with technology, creating new care options and dimensions for people with disabilities.

00:04:01: So first of all, let's walk into this aspect of amputation.

00:04:10: Amputation, first of all, as a layman, you can just see, well, something is missing.

00:04:15: You miss a limb.

00:04:18: Well, if you look at amputation, it's not only mechanics which we can see, but it's also nerves, it's the muscles, it's the brain's map to the body which has changed.

00:04:28: Can you tell us more about that?

00:04:30: This is pretty interesting that you see it so differently because for actually... thousand of years or when the first amputation was documented back in the sixteenth century, it was just cutting off something what is bleeding, what is infected to make the injured people survive.

00:04:51: But it's more and this paradigm changed recently and actually technology pushed surgery to adapt to these possibilities.

00:05:02: So it's true, it's not only, I mean, the principle in the traditional amputation surgery is to take what is left over, so the remaining bone, the muscles, the skin, and to wrap it around the bone that we have got mechanically.

00:05:20: cushion.

00:05:21: But now with technology and starting in OR like with microscopes and later on with the prosthetic and assistive devices, we want to read all the information we have left over in the residual limb, meaning there are still all the nerves who supplied the missing part of the limb, so the hand or the foot or the ankle joint, the knee joint.

00:05:43: And we have the skin and the skin is like the biggest organ of our body.

00:05:48: So we feel through our skin and it's our immune system too.

00:05:53: So we want to use all the different compounds of the residual lymph.

00:05:58: So skin, bone, muscle to use them as interface to read out the information and to really take advantage of all the information they can deliver to the assistive slash.

00:06:11: prosthetic device.

00:06:13: Yeah,

00:06:13: let's walk step by step.

00:06:15: So first of all, just imagine you have a patient who has undergone an amputation and then something comes up which is called phantom limp pain.

00:06:28: So you don't have a hand, but you feel it.

00:06:32: You don't have a leg, but all the same, the body seems to be remembering this missing limp.

00:06:40: So the body, well, forgets, but the brain does not in a certain way, isn't it?

00:06:46: True, that's true and this actually is an advantage.

00:06:50: It sounds weird because this, I mean a lot of patients when they hear how I'm gonna lose my leg, yes, they are frightened of all what's coming up to regain mobility and independence, but second question latest is and what about all the pain?

00:07:09: So there's a difference between phantom limb pain, what is really pain and phantom limb sensation and what you described is more or less phantom limb sensation.

00:07:21: So all the information of the missing limbs are still stored in our brain because we still have the peripheral nerves.

00:07:28: So there are missing pieces of the peripheral nerves.

00:07:32: It's what was in the amputated part of the extremity, but we still have the whole, like, highway from the mist-limbed through the spine to the brain.

00:07:47: And this can be very... I mean, this is an advantage when you later on try to control your new arm or leg.

00:07:56: So, if you still have the possibility to remember how it felt like, it makes later on in therapy rehabilitation way easier to regain the possibility of controlling the assistive device.

00:08:13: This reminds me of a talk I heard.

00:08:16: This is something like over ten years back.

00:08:20: I was in San Francisco and I attended a lecture by VS Ramachandran.

00:08:30: and he worked with mirrors and this was something mind-blowing to me.

00:08:34: so perhaps you can you can just walk us in.

00:08:38: you certainly know the technique but this is dealing with something very simple which is a mirror and this was a break true in first of all treating phantom pain.

00:08:51: Perhaps you can just explain how that works.

00:08:54: Yeah, it's still the gold standard.

00:08:56: So to mirror with a simple mirror, the missing limb, so the arm or the leg, because nerves are not only motor information, it's mainly sensory information.

00:09:10: So just to make it clear so that because perhaps people ask and says, what do you do with the mirror?

00:09:17: So I have two arms.

00:09:19: Now just imagine I have one missing and I place a mirror so that I sort of seem to see the missing limb, which is naturally the one I still

00:09:30: have.

00:09:31: And then if I do an action, it sort of, you know, while simulates that you have two arms instead of one.

00:09:38: That's, I think, the setup.

00:09:40: Exactly, you fool the brain and what you give back.

00:09:44: we still struggle with restoring sensation but one sensory input is visual input and this you replace by mirroring the healthy limb and trumping fooling the brain that there is still an arm or a leg.

00:10:02: And then through this additional sensory input you don't have, yes, when you see your residual limp, yes, you see the hand or the arm and this is increasing the sensory input to the brain and improving this miscalculation in the brain when one limb is missing or part of a limb is missing.

00:10:25: This is the mechanism of mirror therapy.

00:10:28: Same is happening when the people start to wear a prosthetic device.

00:10:34: They see a prosthetic hand or a prosthetic arm.

00:10:39: So this is based on the mechanism of mirror therapy.

00:10:43: So it's basically here, well, the compensation, the brain fooling, as you call it, by vision.

00:10:51: But you sort of go one step down and you say, I don't want to fool the brain in the sense that I now use a different sensor vision, but I use the nerve itself.

00:11:03: I stimulate the nerve and you sort of have a return of sensation.

00:11:10: You call this technique targeted muscle re-innovation, I believe.

00:11:14: So basically, you start looking at the nerve and looking at the input of the nerve if you do a certain action.

00:11:23: as a layman, what I understand?

00:11:27: Yes, this is true.

00:11:29: So we use the residual nerves within the residual limb and we rewrote them to a muscle which after amputation is biomechanically not any longer relevant.

00:11:43: So imagine you have lost your whole arm on the level of the shoulder, your pec major muscle and the latissimus dorsi muscle which are at the trunk on the chest.

00:11:54: You don't need them any longer because the original function of those muscles is to push the arm towards the body.

00:12:03: You don't have an arm, so those muscles basically lost their function and you can sacrifice them and re-root the hand nerves on the breast muscle or on the side, on the lateral side, on the latissimus dorsal muscle, on the shoulder muscle.

00:12:19: and then those muscles serve as bio-booster.

00:12:22: because we still have a lot to go and one challenge bottleneck still is to read the signals directly out of the nerves.

00:12:32: So there are certain approaches in many many research groups to try to read with electrodes the signals out of the nerve but nothing so far is ready to be used in real life and in clinical application.

00:12:47: So the muscle serves as kind of bio booster to code the motor signal.

00:12:56: A second technique called an analogy targeted sensory re-innovation is using skin.

00:13:04: we don't need any longer.

00:13:06: So first of all you need to denervate the muscle and the skin from the original task and then you rewrote very important fields like the fingertip nerves and hand opening and closing is a really important function and elbow flexion and extension to those muscles which you can sacrifice.

00:13:29: Now, let me just understand.

00:13:33: So you take, in fact, the nerve, which normally would connect to my, let's say, the finger movement, you reconnect it to a totally different muscle.

00:13:44: And now if I. imagine or think, okay, I will move my fingers.

00:13:52: I sort of have a muscle here, which gets active.

00:13:54: Is that

00:13:55: how

00:13:56: I

00:13:56: think about finger movement?

00:13:58: and the chest muscle is twitching.

00:14:00: And now, first of all, this sounds a bit like, well, you displace a body.

00:14:07: So suddenly, you know, you think of a finger and a muscle here fires off and you tickle yourself in a different way.

00:14:16: First of all, this is, well, reconnecting muscles and nerves, but different muscles.

00:14:23: But what is the impact if I have an amputation?

00:14:26: What is the difference?

00:14:28: So with this reconnection, we are able to go on another level from the very tiny micro level nerves.

00:14:37: We out of a sudden increase the thickness when the muscles twitching, or we feel it in a bigger field.

00:14:45: on the skin, overlying the residual lymph.

00:14:48: And then we can use what medicine is using for a long time, for example, to track and to observe and to monitor the heart action, what is called EMG, electromyogram.

00:15:01: So we have electrodes, which you can stitch, I mean, on your or actually you can stick them to the overlying skin and muscle and then you are able to capture the electricity of the muscle.

00:15:18: through this EMG electrode and this is not invasive it's established it's pretty reliable.

00:15:25: it's not perfect yes but this enables that we can read the signals out of the hand which is missing or the foot or whatever.

00:15:35: yes so this rerouting we can do at different body parts.

00:15:39: it's always the same mechanism And this electrode is then connected to the prosthetic device.

00:15:46: And the prosthetic device, each EMG signal, the muscle signal, is coding a certain moving pattern.

00:15:56: And then this is the way how the empathy can still code hand movement even though there is no hand any longer.

00:16:06: So to make it very clear, you sort of take the nerve, you map the nerve to a different muscle as an interface if you want, and use the signal of the muscle then to electrically control your, well, prosthetic device.

00:16:25: Exactly.

00:16:26: That's sort of the electrical setup.

00:16:29: I'm a physicist, so we think perhaps more simpler, but so this is sort of an interface you use.

00:16:35: Exactly.

00:16:36: So a myocontrol prosthetic device.

00:16:41: This is a feasible, available option.

00:16:45: Patients can be treated after amputation.

00:16:48: What is already I mean kind of standard, not for everybody, because we have other boundaries to overcome like the health system, but this is a stable, safe connection of the body to the prosthetic device.

00:17:03: Now, just imagine I would be a patient and you just performed this sort of well, rerouting of the nerve.

00:17:11: If I touch sort of this muscle now, which is not my hand, would it also in the direction in the opposite direction give me the impression that oh i'm touching my finger.

00:17:25: is it just one way or two way?

00:17:27: yes so you can do this in a targeted way.

00:17:32: so to really define a skin territory where you connect a sensory part of a nerve and this is core tsr.

00:17:39: but as i said in the beginning the nerve is always mixed.

00:17:43: So if you perform TMR, the overlying skin, the sensory nerves will find the overlying skin.

00:17:50: and then yes indeed you have when you shower and water is running down your chest, you feel parts of your hand according to the nerve.

00:18:01: This is quite spooky sometimes.

00:18:03: Weird, isn't it?

00:18:06: You touch a certain body part and you sort of have the sensation that something else is happening in your body.

00:18:13: So you remap a bit our body in a certain way.

00:18:19: Now, just a question.

00:18:21: I mean, if you are performing these, well, the surgery, how... complicated.

00:18:29: Does it work with every person or are they just very specific patients where you say, okay, here it works and with others, no chance?

00:18:37: Yeah, I mean, there are certain requirements and to really use it as prosthetic control.

00:18:44: First of all, the cognition of the patient, you need to be sure that this is a long way because neurophysiology So nerve regeneration is unfortunately very slow.

00:18:56: So I mean the peripheral nerve in contrast to the brain has the ability to to regenerate what is good.

00:19:04: So it's growing every after an injury.

00:19:06: It's growing every day a millimeter more or less.

00:19:10: So the distances are quite big.

00:19:13: So fifteen, twenty centimeters sometimes say they need to overcome.

00:19:17: to recruit the whole muscle.

00:19:20: So the chest muscle is a good muscle.

00:19:23: It's big and up to fifteen centimetre of distances its nerve needs to regenerate.

00:19:28: So the patient has a very long surgery.

00:19:31: It's microsurgery.

00:19:33: It needs time.

00:19:34: It's a surgery in between four to six hours to reconnect the nerves to the residual muscles.

00:19:42: And then he will have a numb chest.

00:19:47: And then slowly the patient feels the regeneration process with so he can and this is what is in the rehabilitation protocol.

00:19:57: They should do motor imagery of hand movements of leg movements wherever you do it here.

00:20:03: This is part of the rehab.

00:20:04: So we need patients who are very compliant understand the procedure Do their homeworks collaborate with us and this is for me the major requirement.

00:20:17: and then indeed I mean you need to select the patient who can tolerate yes a six hour surgery maybe here and so if somebody has a lot of comorbidities this might not be a good solution for this patient.

00:20:33: First

00:20:34: of all, the surgery, let's go step by step.

00:20:37: It's fascinating.

00:20:39: The surgery itself, I mean, this is, I imagine, you know, if you take... a technician an electrical technician he would rewire something.

00:20:51: this is something i can see.

00:20:52: but now you are doing this on a micro level.

00:20:57: so first of all the search itself.

00:20:59: you have to make sure i this is the nerve this is this specific nerve i can imagine this is.

00:21:05: Well, highly complicated identifying nerves, connecting nerves.

00:21:11: I don't know how you connect nerves.

00:21:14: This is technically, I mean, with electrical wiring, I could give you an answer, but here it seems to be more complicated.

00:21:22: So these six hours is really strenuous, very precise work.

00:21:28: It is, it is.

00:21:30: But the comparison to electrician is really good.

00:21:34: So we just renovated our house and when the electrician came, he was like, because we changed the room of the kitchen and all the wires needed to be rewired, I was thinking, actually, we have the same job.

00:21:49: So the comparison is a really good comparison.

00:21:54: And I use it when I explain the procedure to the patients.

00:21:58: So we are definitely rewiring.

00:22:01: And yes, we first of all need to identify the nerves, which are tiny.

00:22:06: They look like little white cables.

00:22:09: And then we stimulate them with electrical stimulation to identify which nerve it is.

00:22:17: And sometimes it's not possible because, I mean... the muscles are lost and when we stimulate the response of the stimulation is a muscle contraction.

00:22:27: So then we need to rely on our anatomy skills we have here and then we go to the target muscle, so muscle we want to sacrifice and we need to find the motor branch going into the original motor branch going into that muscle.

00:22:45: Then we dissect the original nerve and reconnect on the nerve which is entering the muscle, the target nerve.

00:22:59: I mean, actually the identified nerve to the target nerve.

00:23:02: The target nerve is the one already, you're still in the muscle of the original.

00:23:06: And then the hand nerve, for example, grows along the original nerves, yes, into the muscle and is re-enervating them according to the hand nerve function.

00:23:22: So you are the great, great, great granddaughter of Luigi Galvani.

00:23:26: You remember the experiment with the frog legs where he found out that while you have the nerve and the contraction of the frog, he used this to prove the presence of electricity.

00:23:36: But here, this is also an electrical signal in a way which sort of gives you the opportunity to interface it to an electrical device which then would control, well, a prosthetic hand or something like that, correct?

00:23:54: Exactly.

00:23:55: Now, you spoke about rehabilitation.

00:23:59: So after you did your intervention, the body has to remap and learn.

00:24:05: So this is, I think, so rehabilitation, I would call it reprogramming in the sense that, well, you now have to do exercises in order for the body to understand the new

00:24:16: map.

00:24:17: Exactly.

00:24:18: Exactly.

00:24:18: We still use the original highways.

00:24:22: This makes it so easy.

00:24:24: So before, I mean, there was my electric control too, but then the patient needed to learn, okay.

00:24:30: contracting my chest muscle means opening my hand.

00:24:34: Now with this new technique, TMR, rerouting the nerve, the patient thinks of hand moving, hand closing and opening.

00:24:43: And this is way more intuitive, as we say, and everybody is aiming for intuitive control, but still we need to train the patient.

00:24:52: So a key stakeholder in this whole process are the therapists.

00:24:58: We have the surgeon, we have the medical doctors, but very important, and therefore this is a team approach.

00:25:07: We have the CPR, the certified prosthesis and orthosis, and we have the therapist, the occupational therapist and the physiotherapist.

00:25:16: They need to support, and they're way better in that than I am, to rebuild the new body image.

00:25:25: Now, if you take the entire timeline, I mean, this is highly complex.

00:25:29: I mean, you spoke about the operation taking five, six hours already, and then you have, well, all the other steps of rehabilitation, of getting used to it, of retraining, of a nerve which is growing.

00:25:46: All in all, this entire process would take, what, half a year until you sort of feel the reaction and you sort of can use it?

00:25:57: First movement and sensation you feel after six months, but the entire... Yes, I mean, I always tell the patient it can take up to one and a half, two years.

00:26:10: until they can go home with the prosthetic device and use it at home in a reliable way.

00:26:18: And it's better because expectation management with all the media talking about high-tech prosthesis is important.

00:26:28: We have great opportunities way better than ten, fifteen years ago, but we don't want to disappoint our patients and therefore it's nice, maybe this can happen quicker, but there are some factors which we cannot influence, like reimbursement questions and sometimes they need a break because they are struggling with the new situation and then they can't have this cognitive overwhelming and challenging training every day.

00:27:05: So it's good to do it in a chilled way, to smoothly support them adapting to the new possibilities.

00:27:15: That's a very important point you mentioned, which is,

00:27:18: well,

00:27:19: have clear expectations.

00:27:21: This is perhaps also the reason why we do this podcast, A Taste of Bionics, which is not pinning up a future, which is easy to know.

00:27:31: This requires, as we understood, hard patient work, a lot of resilience.

00:27:37: But at the end, you gain something.

00:27:40: Now, do you have an example of a patient where you could give us the idea of the before and after this treatment?

00:27:49: Yes.

00:27:51: What is very nice, so when we have two different groups of patients, so the group of patients, we do all this.

00:28:02: the bionics, yes, within the primary amputation.

00:28:05: This can be a tumor patient.

00:28:08: This can be a trauma patient.

00:28:10: So coming in, needing treatment, immediate treatment or very, I mean, very soon treatment.

00:28:18: And then we do all this as much as possible.

00:28:22: rerouting the nerves and then there is a technique for the muscles called Amy and etc.

00:28:29: in one in the primary amputation.

00:28:31: So then the patient does not have any comparison I mean because that patient has never experienced the traditional on average amputation.

00:28:43: And then we have the patients who are already amputees and who have problems and we have talked about so far about the gain of function.

00:28:55: But what is very important and this is a major motivation to go for that second group of patients, the amputees who are already amputated in a traditional way.

00:29:06: It's pain.

00:29:07: So you can have pain after amputation, like phantom limb pain.

00:29:13: You can have pain from the nerve and what is called neuroma pain because nerves, they are very, very, very motivated structures.

00:29:25: they grow, as we have talked about, and when they grow, uncoordinated, because they're only cutted and they are, I mean, lying there without any work, yes, not attached to their muscle, to their end organ or the skin, they signal to the brain, yes, sorry, I don't like it, I don't like it, I'm unemployed and give me something to do, and this is called neuroma pain, it's a tingling, it's an uncontrolled electricity.

00:29:52: what the patient feels.

00:29:54: And often those nerves are lying very close to the skin and pressure is something what nerves do not like.

00:30:03: So when they try to put on their prosthetic device and the socket, this pressure is eliciting electricity and this pain.

00:30:12: So this is actually the common way that the patient come to our outpatient clinic and say, I have nerve pain, I have phantom limb pain and can you please help me?

00:30:24: And there are ways to adapt the socket, the prosthetic device, yes, to relieve them from the pressure points, but we have those techniques and this is what we've learned in the run of this, I mean in the course, out of the experience with this new surgical techniques, that those are decreasing.

00:30:45: Amputation associated pain like residual limb pain, like phantom limb pain, like neuroma pain, those are the three big classes of pain.

00:30:56: Empathies can be confronted with.

00:30:59: So there, I can imagine, I mean, you have had patients.

00:31:06: Do you have a story of a... person who came there with an amputated leg in a well traditional or old-fashioned and Then you sort of you know intervene and they feel relieved.

00:31:22: I mean How is that for the patients themselves?

00:31:26: It's I mean this is something that's always the nicest moment.

00:31:30: when they first come in and they look tired they have I mean rings shadow rings around their eyes and they complain about pain and they are in a wheelchair and when they come for the post-op control some months later they're walking.

00:31:50: and I remember that one patient I have never seen him in his prosthetic device always in his wheelchair.

00:31:58: and then I met him for his follow-up and he was standing in front of me and I told him, oh my God, Mr.

00:32:07: X, epsilon, you are so tall.

00:32:09: And he said, yes, I'm so tall.

00:32:12: This is what the girls like.

00:32:14: And now I'm back to impress them.

00:32:17: And this is, I mean, it was funny, but it showed, I mean, everybody wants to be.

00:32:24: I mean, nobody wants to be in a wheelchair.

00:32:26: Nobody... I mean, this is the way how you talk to the patient.

00:32:28: When they're on the wheelchair, you talk down to them, yes, because you're usually standing, yeah?

00:32:33: And those are the little details which really, I mean, impact their life.

00:32:41: Nobody wants to feel like a patient for its whole life, yes, or somebody needing help, support.

00:32:48: Pain can be a power drain and you cannot sleep and this is changing the personality.

00:32:54: So all those effects, those techniques can have, yes, on the different categories of life.

00:33:00: So in other words, what is very important here is that you have a sort of a... broad impact of your work.

00:33:09: So it's not only looking at nerves and stimulation of muscles, but it's psychology.

00:33:16: It's the whole way you feel, which is a loop where people perhaps even get better and better.

00:33:22: I mean, if you feel better, you have more energy, you have more resilience, and you carry on.

00:33:28: So this is also cutting this sort of loop, which normally goes in the other direction.

00:33:34: Yeah, the best outcome is when you can, yes, interrupt this vicious circle of pain, inability, lack of sleep, medicaments, not being able to participate in life, not being able to work, et cetera, et cetera.

00:33:53: And mobility is a big supporter of regaining your body image because we define ourselves through mobility.

00:34:02: Now, we spoke about, well, the nervous system reconnecting, suppressing pain in a way.

00:34:12: But let's talk a bit about feeling.

00:34:15: So, I mean, one thing is, can I activate, for example, a prosthetic arm or a hand?

00:34:24: The next step would be sort of the opposite direction.

00:34:28: Can I sort of... regain feeling of saying, hey, this is really my arm.

00:34:34: I feel it that way.

00:34:36: Yes.

00:34:37: So it's possible.

00:34:40: It's not possible in the very authentic way.

00:34:45: This is something we definitely need to work on.

00:34:48: But there are some, let's call it easy basic primitive ways of restoring sensation.

00:34:58: Actually the here we have the possibility to go to.

00:35:04: I mean a nerve for example the hand nerves.

00:35:07: I mean we have multiple hand nerves and we don't have the amount of targets you need to to mirror the fingertip and the palm and everything in that.

00:35:19: Yes, I mean, how do you call it solution resolution?

00:35:22: Yes, so we need to decide what is important and what do we want to remap when we decide which enough to target.

00:35:31: And then you have this hand map.

00:35:34: Let's stay on the arm.

00:35:35: It's always a very easy.

00:35:38: or easier explanation.

00:35:40: When somebody is forearm amputated, you have kind of a reflection of the hand after this procedure.

00:35:47: When you take the sensory nerve, you connect it to the skin.

00:35:52: We still need the interface.

00:35:55: So how do we stimulate this skin?

00:36:01: according to the function of the prosthetic device?

00:36:03: So when the prosthetic hand is grasping that those Spots are stimulated via and so there are different ways via electrical stimulation via Vibrotector stimulation We are pretty far away from mechanical stimulation.

00:36:23: What is actually the most authentic intuitive and original way?

00:36:29: because make Cannotactile actuators are very complex and you need to build them into the socket and there are some bottlenecks from a mechanical standpoint how to later on build the prosthetic device.

00:36:43: So a common way is to use Vibrotactile stimulation.

00:36:47: Vibrotactuators can be very small and they work reliable and then the touch of the fingertips is coded into vibration and the vibration is stimulating those skin territories.

00:37:00: Hmm.

00:37:01: So it's literally, uh, we, this is also very individual because, you know, one person is different.

00:37:08: Every patient is different.

00:37:10: So you don't have a standard technique which you use, but this is, you have to decide on every patient.

00:37:17: Okay.

00:37:17: How do I map it to?

00:37:18: what muscle here with the other person, perhaps do another, uh, part of the skin.

00:37:24: So, uh, there is no standard right now.

00:37:28: or do you see alleys where slowly we have sort of standard procedures in such amputations?

00:37:36: There are some recommendations.

00:37:39: and which muscle and which nerve target to which muscle or which nerve, sensory nerve is important.

00:37:47: For example, when you let's go back to the hand.

00:37:50: So the thump sensation and the second digit, the index finger is very important because most of the grasping patterns are translated by this pinch.

00:38:03: So the pinch is something new.

00:38:04: I mean, the sensation of this is very important.

00:38:07: Then the elbow function is very important because it's nice to have hand movements, but it's important to be able to to put it where you need it.

00:38:19: So elbow function is something what is really important.

00:38:23: Hand closure is very important.

00:38:24: So we go into surgery, we see how many targets we have and then we decide according to the most important functions what to connect with, which structure connect to what?

00:38:40: muscle and nerve and skin.

00:38:43: you know jenny our podcast is called a taste of bionics biology and technology and if i listen to you i think so.

00:38:54: first of all one must be aware of this sort of miracle of nature of this wonder of complexity of nerves.

00:39:02: so i think so most lemon.

00:39:04: underestimate the complexity of the body.

00:39:10: Is this hybris in a sense that well we have a highly complex biology and now we sort of use technology to slowly adapt?

00:39:20: or do you see an alley where with progresses in technology in computers and electronics in some years we even might be able to at least come closer to what nature has

00:40:02: let?

00:40:02: the empathy communicate with?

00:40:05: the assistive device are still not as perfect as biology, as evolution of humankind was actually enabling us to do all the things we do in our daily life.

00:40:20: So I hope for that.

00:40:22: we have a groundbreaking technique and this might be that we read the signals of nurse in a reliable way.

00:40:32: or that we have a lot of sensors which can anticipate the movement or the patient wants to do.

00:40:42: So I don't know if this I can imagine are two LA's who might improve faster than hopefully expected the technology in this whole field.

00:40:54: Well, you see in the world of... AI, people very often speak about the digital twin.

00:41:01: So you have reality and then you map reality in an isomorphic way to the digital world, the world of, well, different variables and so on.

00:41:15: This is slowly.

00:41:16: the granularity of this is getting smaller and smaller.

00:41:22: Do you see in the future developments where this sort of mapping will be crucial for patients not only in controlling an artificial limb, but also to regain a sense of feeling your body?

00:41:41: Yes, it's quite interesting and it's good that we have the option with the digital twin not skin.

00:41:48: So because then we can...

00:41:50: Yeah, it could be a digital skin in fact.

00:41:52: Yeah,

00:41:53: it could be a digital skin too.

00:41:56: But the digital twin idea does allow for test run without involving human beings.

00:42:04: And this I think it's great.

00:42:06: Yes, all the simulation and so on.

00:42:10: Can enable experiments we need to test run without involving human beings and to accelerate technology research and development?

00:42:25: Jenny, you are also training surgeons around the world.

00:42:29: So you have many young colleagues.

00:42:35: How do you sort of... get away with the balance between technology the fascination of nerves of science on one side and empathy towards the patient on the other side?

00:42:47: because i think so we should not get lost into.

00:42:50: you know just looking at the technology it's all.

00:42:54: it's a human question at the end isn't it?

00:42:57: it is it is.

00:42:58: and to select and to recommend and to give the options i mean you need I mean, it's good to pre-select the options for the patient, yes, because we talked about expectation management.

00:43:13: Yeah, so why to offer something more that's not reachable for this patient to a patient when he comes with a problem or she comes with a problem.

00:43:22: So, you need empathy, but you learn it.

00:43:27: I think this is a major requirement when you work as a medical doctor.

00:43:31: And in this field, It's so amazing and this I can see in the residents who are with me working and in the beginning they sometimes don't know what amputation means.

00:43:45: I mean they have this picture we all have in our mind and society has in mind of completely I mean just losing something.

00:43:54: And then they see the in the outpatient clinic every Monday we are together with the therapist and with the technicians and engineers and we combine clinical research with patient treatment with clinical routine.

00:44:09: And they see how the patient develops, they see the possibilities of technology, but we see the patient for a very long time.

00:44:18: So in the beginning we see them like once a month.

00:44:22: And we see the small steps the patient is accomplishing every time, yeah?

00:44:27: And then we schedule a follow-up once a year and we call it like in German it's called TÜV, so the car needs to go to the checkup every year or every other year.

00:44:38: And those patients come and then we check if everything is fine.

00:44:43: And so it's amazing to see.

00:44:45: I mean, they have this... Yes, I mean... injury or trauma or tumor.

00:44:54: and then they have this whole reputation protocol.

00:44:57: and then they come again and sometimes they bring their kids, they bring their new spouses, they bring whatever or they show us what they have done or they sent us pictures from competition where they participated or that they went back to vacations and diving, scuba diving.

00:45:15: or surfing, skiing, etc.

00:45:18: And this makes it for us very easy to have empathy and to be humbled, actually.

00:45:27: So what I understand is also this is a long-term relationship.

00:45:31: This is not, you know, the fast and Well, one spot change, but this is a long, long process.

00:45:40: Well, if you could change a thing, I mean a policy, a training rule, a funding structure, what would help the most patients the fastest?

00:45:52: What is... Well, do you have suggestions?

00:45:57: Yeah, what is actually, I think... quite easy to establish and would have a lot.

00:46:02: So at least in the German system, healthcare system, I think it's true for many countries.

00:46:09: We have the clinical sector and we have the outpatient clinic sector.

00:46:15: And the communication between when the patient is in-house, in-patient and outpatient is so separated that it causes a bunch of administration and a zillion of documents to be filled out for the patient, what is really slowing, yes, and sometimes, I mean, stopping the process of rehabilitation.

00:46:41: So, if there might be, I mean, for a certain kind of injury, like an amputation, a healthcare advocate who supports the patient to manage all those administration things, like getting back the driver's license, yes, I'm talking to the insurance, yes, or making sure that the following steps are done by the patient itself.

00:47:05: I think this would improve the quality and the satisfaction of every stakeholder involved in this process.

00:47:13: So in other words, the big challenge is not only biology, it's bureaucracy, it's, well, getting a system to run faster, which is true in many areas, but naturally here it's very existential.

00:47:28: If you look into the future, you mentioned, well, cyborgs, there are always people who sort of say, oh, could you also enhance something with a, well, a person who did not suffer an amputation?

00:47:44: Is that also an area where you are thinking of, or is this just, well, science fiction and something which is not correct here in this context?

00:47:55: This is some very delicate discussion, I think, we can slip into.

00:48:03: Yes, I mean, augmenting humanity.

00:48:06: I mean, let's call it like this.

00:48:09: But hearing aids and glasses, I mean, this is already augmenting humanity.

00:48:17: So, this is a discussion we need to talk about before we are stepping into those possibilities.

00:48:27: I think we are far away of that.

00:48:31: people come and want to have an amputation to be faster.

00:48:36: I mean, let's get back to how perfect evolution is and how perfect our body is and a healthy body is something everybody should be very thankful for.

00:48:53: Yes, but I think especially when we look towards the aging society, maybe what we learned out of the field of amputation or spinal cord injury treatment with assistive devices can help to improve the quality of life of our elderly people living with us.

00:49:18: augmenting humanity too, in a light way maybe, but this is not only quality of life for them.

00:49:26: We reduce the risk of falling, the load for the hospitals of those people in the hospital, and there might be a sustainable effect when we use technology to augment humanity in a quality and way.

00:49:44: Yeah, well, it sounds strange, but you already gave some very clear aspects.

00:49:49: I mean, my spectacles, hearing aids, some patients even have, you know, if you just look at what we did with the heart of stents of, you know, technology entering that field.

00:50:04: So could you think of, I mean, just this is, well, looking into the future.

00:50:11: of an application where you would say, Ranga, you are right now a grandfather.

00:50:18: I'm a young mother.

00:50:20: And in some years, Ranga, you will suffer this and that, and I could help you.

00:50:25: What would that be?

00:50:27: I mean, let's... So certain developments of reestablishing the... ability to walk might help you.

00:50:39: So imagine, I mean, this is a very biological process that even you are a very sporty person and you live healthy and you go to the gym, muscle mass is decreasing over time.

00:51:00: You can decelerate this process, but you cannot stop it.

00:51:04: And imagine, I mean, you can put on a bandage or orthotic device, an exoskeleton, and you're still able, with this assistive device, to go out for a walk and have fresh air, move yourself.

00:51:19: I think this would be, this is a scenario we should think of when we talk about augmenting humanity.

00:51:29: And I think this is not so far away.

00:51:33: And there's a wide field of application.

00:51:38: Aging Society will be a big challenge for us.

00:51:41: So in the future, if I look at my personal future in,

00:51:45: I don't

00:51:46: know, perhaps twenty years, I could have an exoskeleton because I'm unable to really walk.

00:51:53: And this exoskeleton, thanks to your research, would also give me some feeling, some stimulation.

00:52:01: Is that a vision or is that just, well, wishful thinking?

00:52:05: Yes.

00:52:05: I mean, we could support those people to regain mobility.

00:52:15: and then with all the effects coming with mobility.

00:52:19: Yes, we get stimulation, sensory stimulation, but it's just the easy way to be able to go out and breathe in free, I mean in air, in nature, to connect with other people, to leave home, to leave loneliness.

00:52:37: Those are all factors which... Out of the sudden, might be able with the simple fact to go out for a walk again.

00:52:49: Well, all these stories remind us that beneath all signs, it's I think so also about dignity, agency, the feeling of well, being a whole person as such, which is the underlying motivation, isn't it?

00:53:06: Yeah, exactly.

00:53:08: Very nice words you found to describe that.

00:53:11: Well, Jennifer, for our listeners, engineers, clinicians, what is a piece of advice?

00:53:22: I mean, we will have many people in that field also listening to this podcast.

00:53:28: What is a piece of advice you would give these people?

00:53:34: To never forget the respect towards the human body.

00:53:38: and mine

00:53:39: and for the human perhaps itself.

00:53:41: The human body and the mind.

00:53:43: Yeah.

00:53:43: Yeah.

00:53:44: Well, Jennifer, thank you for the science, but also for as I just mentioned, the humanity behind it.

00:53:52: Your work shows that Bionic is not a doll replacing people by machines.

00:54:00: It's about, I would put it that way, letting people feel human.

00:54:07: Again and well it's great that you were with us.

00:54:12: great research and we speak.

00:54:15: in twenty years I got that idea of the exoskeleton.

00:54:19: and well once again thank you to everybody listening.

00:54:24: if this.

00:54:26: Episode inspired you well.

00:54:28: Share the episode and explore naturally.

00:54:32: Jennifer's research.

00:54:33: I am Ranga Yogeshwar.

00:54:35: Thanks for joining Taste of Bionics.

00:54:38: And many, many thanks to Jennifer.

00:54:42: Stay curious.