Brachial Plexus Injury

Podcast Transcript

Neuro Pathways Podcast Series

Release Date: June 15, 2025
Expiration Date: June 14, 2026

Estimated Time of Completion: 30 minutes

Brachial Plexus Injury
Megan Jack, MD, PhD and Dennis Kao, MD

Description
Each podcast in the Neurological Institute series provides a brief, review of management strategies related to the topic.

Learning Objectives

• Review up to date and clinically pertinent topics related to neurological disease
• Discuss advances in the field of neurological diseases
• Describe options for the treatment and care of various neurological disease

Target Audience
Physicians and Advanced Practice providers in Family Practice, Internal Medicine & Subspecialties, Neurology, Nursing, Pediatrics, Psychology/Psychiatry, Radiology as well as Professors, Researchers, and Students.

ACCREDITATION

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• American Medical Association (AMA)
  Cleveland Clinic Center for Continuing Education designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
  
  Participants claiming CME credit from this activity may submit the credit hours to the American Osteopathic Association for Category 2 credit.

• American Nurses Credentialing Center (ANCC)
  Cleveland Clinic Center for Continuing Education designates this enduring material for a maximum of 0.50 ANCC contact hours.

• Certificate of Participation
  A certificate of participation will be provided to other health care professionals for requesting credits in accordance with their professional boards and/or associations.

• American Board of Surgery (ABS)
  Successful completion of this CME activity enables the learner to earn credit toward the CME requirements of the American Board of Surgery’s Continuous Certification program. It is the CME activity provider's responsibility to submit learner completion information to ACCME for the purpose of granting ABS credit.

Credit will be reported within 30 days of claiming credit.

Podcast Series Director
Andreas Alexopoulos, MD, MPH
Epilepsy Center

Additional Planner/Reviewer
Cindy Willis, DNP

Faculty
Megan Jack, MD, PhD
Center for Spine Health

Dennis Kao, MD
Plastic Surgery

Host
Glen Stevens, DO, PhD
Cleveland Clinic Brain Tumor and Neuro-Oncology Center

Agenda

Brachial Plexus Injury
Megan Jack, MD, PhD and Dennis Kao, MD

Disclosures

In accordance with the Standards for Integrity and Independence issued by the Accreditation Council for Continuing Medical Education (ACCME), The Cleveland Clinic Center for Continuing Education mitigates all relevant conflicts of interest to ensure CME activities are free of commercial bias.

The following faculty have indicated that they may have a relationship, which in the context of their presentation(s), could be perceived as a potential conflict of interest:

Glen Stevens, DO, PhD

DynaMed Consulting

All other individuals have indicated no relationship which, in the context of their involvement, could be perceived as a potential conflict of interest.

CME Disclaimer

The information in this educational activity is provided for general medical education purposes only and is not meant to substitute for the independent medical judgment of a physician relative to diagnostic and treatment options of a specific patient's medical condition. The viewpoints expressed in this CME activity are those of the authors/faculty. They do not represent an endorsement by The Cleveland Clinic Foundation. In no event will The Cleveland Clinic Foundation be liable for any decision made or action taken in reliance upon the information provided through this CME activity.

HOW TO OBTAIN AMA PRA Category 1 Credits™, ANCC Contact Hours, OR CERTIFICATE OF PARTICIPATION:

Go to: Neuro Pathways Podcast June 15, 2025 to log into myCME and begin the activity evaluation and print your certificate If you need assistance, contact the CME office at myCME@ccf.org

Copyright © 2025 The Cleveland Clinic Foundation. All Rights Reserved.

Introduction: Neuro Pathways, a Cleveland Clinic podcast exploring the latest research discoveries and clinical advances in the fields of neurology, neurosurgery, neuro rehab, and psychiatry.

Glen Stevens, DO, PhD: Brachial plexus injuries which affect the network of nerves supplying the arm and the hand can result in significant impairment. In today's episode, we dive into management of these injuries, which require careful monitoring to determine the appropriate course of action, including early surgical intervention for optimized long-term outcomes. I'm your host Glen Stevens, DO, PhD, neurologist, neuro-oncologist in Cleveland Clinic's Neurological Institute. And joining me for today's conversations are Dr. Megan Jack, MD, PhD and Dr. Dennis Kao, MD. Dr. Jack is a peripheral nerve neurosurgeon, and Dr. Kao a plastic surgeon, both members of the multidisciplinary brachial plexus program at Cleveland Clinic. Megan and Dennis, welcome to Neuro Pathways.

Dennis Kao, MD: Thank you.

Megan Jack, MD, PhD: Thank you for having us.

Glen Stevens, DO, PhD: To start the conversation. I'd like both of you and Megan, you can go first. Tell us a little bit about yourself, how you made your way here and what you do on a daily basis.

Megan Jack, MD, PhD: Sure. So I'm a neurosurgeon at the Cleveland Clinic. I've been here just about four years or so. I specialize in a very small field within neurosurgery where I focus on the peripheral nerve. So while lots of people do brain surgery and spine surgery, I get to focus on kind of the whole body, which is a lot of fun. So I initially did my MD-PhD and then completed my neurosurgery residency and did a fellowship at Mayo where I trained in peripheral nerve surgery and then came here.

Glen Stevens, DO, PhD: Great. Happy to have you. Dennis?

Dennis Kao, MD: So, Megan and I started about the same time at Cleveland Clinic. My training was in plastic surgery, then I subspecialized in hand and peripheral nerve surgery. And so my practice now is essentially a hundred percent hand and peripheral nerve surgery. I do anything involving the hand and then peripheral nerve. So Megan and I teamed up also with Dr. Greg Kwiecien. So the three of us now run the peripheral nerve clinic over at the Neurological Institute.

Glen Stevens, DO, PhD: When I first started, of course, that type of thing didn't exist at all. So it's great to have people interested in these types of things. So I am sure all the physicians out there listening, shaking a little bit when they're thinking about the brachial plexus and we all went through it. I mean, how many times have we drawn out the brachial plexus? And I'm curious, my mnemonic for remembering the brachial plexus, the roots, the trunks, the divisions, the cords, the branches was Robert Taylor drinks cold beer.

Megan Jack, MD, PhD: Oh, yes. Still very common.

Glen Stevens, DO, PhD: What was yours? Same one?

Megan Jack, MD, PhD: Yep, absolutely.

Glen Stevens, DO, PhD: Did you use the same one?

Dennis Kao, MD: Same one. Yeah.

Glen Stevens, DO, PhD: I've seen a bunch of different ones, but that's the most common one. That's the one that we used. I'm sure people out there listening to this probably can relate to it.

Megan Jack, MD, PhD: Yeah, there'll be no quizzes.

Glen Stevens, DO, PhD: When I used to hospital service, I'd always review the brachial plexus before I went on service so I could appear to be smarter than I really was. When I asked the residents the questions and I would quickly forget when I went off service again. So I'm hoping you guys don't quiz me too much out here. So let's go through some brachial plexus injuries and diagnosis, that type of thing. And I don't know, Megan, if you want to go through that to start, but tell us how the brachial plexus gets injured and what types of things you see.

Megan Jack, MD, PhD: Sure. I think it's important to remember that each injury is so unique to that patient. So we kind of approach it at that level. The brachial plexus obviously supplies all of the arm and some of the very common ones that we see are motorcycle accidents, motor vehicle accidents.

Dennis Kao, MD: And then a lot of people fall, and they had a shoulder dislocation or I guess the iatrogenic ones would be people who had shoulder replacement surgery or other types of surgical intervention that's close to the plexus and then inadvertently may be led to partial injury of the structures there.

Megan Jack, MD, PhD: But then typically what we're doing is seeing those patients we hope very early so we can follow their trajectory. Some patients will get better on their own, but others don't need surgery. And so...

Glen Stevens, DO, PhD: When we talk about injury, we have a nerve, we have myelin around the nerve, we have the axon itself. I assume any of these things can get affected? The myelin can get affected, the axon and it can be stretched or talk about the different types of injuries or way the nerve can get injured.

Megan Jack, MD, PhD: Yeah, absolutely. So the ways that we kind of think about brachial plexus injuries are, like you said, whether it's a stretch injury and the nerve is still in continuity and may ultimately recover kind of a damage to the myelin and the axon. Other ones are where they're actually ruptured, so the two ends of the nerve are not connected anymore. And so that's where surgery becomes imperative at that point in time. And then the most severe form is where the nerve rootlets are actually pulled from the spinal cord. And while we have less options for surgery in those instances, we still have a number of options to get back function for patients.

Glen Stevens, DO, PhD: I think the very first patient that I ever saw when I was a very young staff was a guy who had a motorcycle accident and avulsed his nerve roots and it was quite an impressive unfortunate scan and sort of like, "What can I do?" And it's sort of, "Boy, this is a serious problem."

I remember Asa Wilbourn who was before your time, he was really one of the pioneers in EMG electrical diagnostic testing. And he used to get very fired up when people would come in for a brachial plexus evaluation into the lab and he would read through the notes and somebody would write in the note neuropraxia. It was really one of his buzzwords that would just set him off because my collection was that neuropraxia was an implication that all would be fine. That it's a minor injury, probably a demyelinating type process, and it would remyelinate and you would do fine and he would get very unhappy about it because then that's in the medical record and you're saying this person really doesn't have a bad problem and then they test him and they actually have a bad problem. So I guess my advice channeling Dr. Wilbourn back many years ago, be careful using the word neuropraxia-

Megan Jack, MD, PhD: Hundred percent.

Glen Stevens, DO, PhD: ... when they're out there. I guess the other area outside of trauma are things that I would always quiz the medical students and residents on, and that is brachial neuritis, Parsonage-Turner, diabetic amyotrophy, those types of things, which can certainly affect other nerves as well. But tell us a little bit about that disorder.

Megan Jack, MD, PhD: Yeah, so-

Glen Stevens, DO, PhD: Do you see that?

Megan Jack, MD, PhD: We do, and we see it fairly frequently. Part of it is we have to sort of follow the history for that one. So typically it's seen in patients who have really severe pain and then ultimately as the pain resolves, they develop pretty severe weakness and it can look very much like a brachial plexus injury. And specific nerves are usually involved, but we see those patients regularly. I would say 80% of patients do get better on their own from that. It just takes a very long time given the injury to the nerves. But we do see a handful that don't actually get better. And we're actually, I have a study ongoing right now looking at that kind of the natural history. I think that's kind of the teaching, but we again see a handful of patients that at a year haven't really improved at all. And so I think there's controversy in our field about what do we do with those patients.

Glen Stevens, DO, PhD: Yeah, it's a good point. I don't see, I'm a neuro-oncologist, so nowadays I don't see any of that type of stuff. But I recall that sometimes I remember seeing a patient that had a brachial neuritis related to a surgery, and again, it's hard to know what the etiology is. I think a lot of them are viral induced or some type of antigen immunologic disorder where it attacks it, but then recovered and had another surgery somewhere later and had it again. And then it was a question of, well boy, if you need another surgeon, then what do you do? Do you plex these people or you give them IVIG?

Megan Jack, MD, PhD: Yep.

Glen Stevens, DO, PhD: What do you do?

Megan Jack, MD, PhD: We've had a number of patients like that where we've run into difficulties about the decision-making for surgery and what are the ultimate risks that go involved with that.

Glen Stevens, DO, PhD: And then it's weird because some people can also get bilateral brachial neuritis, which it's a bizarre disorder but-

Dennis Kao, MD: Could be bad.

Megan Jack, MD, PhD: And now we know there's a genetic condition for it, that there is a-

Glen Stevens, DO, PhD: A genetic condition for it as well. I always found it, fortunately in my limited career with it, I found it always very satisfying because you could, the story would always, usually would be so classic that when you do the EMG and it would have the classic nerves be affected by it and you could tell most people there's a good reason to believe you should get a nice recovery and most people would with it. But unfortunately you guys deal with some things much more serious than that as it goes through. So the diagnosis, you do the story, you listen to the history, obviously they had a car accident or motorcycle accident. You have imaging, you can see what's there. Do you work with a specific neuromuscular person in your brachial plexus group or it's just any of the neuromuscular folks?

Megan Jack, MD, PhD: Yeah, I would say we regularly work with a number of them. We don't have one specific dedicated one. We would love that eventually, there were some talks about getting there-

Glen Stevens, DO, PhD: Hearing, if you're out there.

Megan Jack, MD, PhD: Exactly. Please come apply. We will take you. But we work with the neuromuscular neurologists for all of our EMG's. We oftentimes, we also rely on some ultrasound evaluation as well for many of our patients. And so we utilize their talents as well.

Glen Stevens, DO, PhD: And the ultrasound tells you about avulsions or it can tell you swelling in the nerve, all those things.

Megan Jack, MD, PhD: Yep.

Glen Stevens, DO, PhD: What does it tell you?

Megan Jack, MD, PhD: A combination of swelling. We're also, like you said, for Parsonage-Turner looking to see if there's hourglassing within the nerve. So yeah, we heavily utilize it for a number of different-

Glen Stevens, DO, PhD: And tell me about the hourglassing.

Megan Jack, MD, PhD: Yeah, so for Parsonage-Turner, some of the new features that-

Glen Stevens, DO, PhD: See, I'm not up-to-date on all the fancy lingo.

Megan Jack, MD, PhD: That's fair. So some of the new features that they have seen at certain institutions are that the nerve is actually hourglassed in the sense that there's areas where it's kind of pinched off or undergoes torsion. And so the thought processes that maybe that's contributing to the actual findings and by decompressing that it could improve their outcomes.

Glen Stevens, DO, PhD: So, there is some potential for surgical intervention if you see that?

Megan Jack, MD, PhD: Correct.

Glen Stevens, DO, PhD: If you don't do surgical intervention, any data to support follow-up ultrasound shows resolution as they resolve, or maybe these people don't get better, or we don't know?

Megan Jack, MD, PhD: Yeah, I'm not aware of the long-term studies. I think mostly if they're seeing it, they're intervening upon-

Glen Stevens, DO, PhD: So, they're jumping in. Interesting. Most common injury that you end up doing surgery on?

Megan Jack, MD, PhD: It's a combination. Most likely, probably upper trunk is one that we've very, probably the most common one that we will intervene upon. I think those are the nerves that go to the shoulder as opposed to if a patient has an injury that goes to the hand. Those can oftentimes be much more challenging just given the length of the nerve that goes to the hand to actually get back function. So we have pretty good surgeries for upper trunk, some surgeries for lower trunk.

Glen Stevens, DO, PhD: And are you seeing many tumors affecting the brachial plexus? I mean, they always just talk about Pancoast tumors and that type of thing in the trunk, and you can sort of define upper versus lower trunk and those types of things.

Megan Jack, MD, PhD: Yeah, absolutely. I mean, I think we have a large proportion of patients, particularly patients that have neurofibromatosis associated tumors or schwannomatosis associated tumors that we take care of. We're actually operating on one on Friday together where I'm taking out one in the arm and he's going to take out one in the finger. So yeah, I think we share those patients very well and we see them pretty regularly.

Glen Stevens, DO, PhD: And do you use electrical recordings during the surgery on the nerves to help you determine the integrity or what the signal's doing?

Megan Jack, MD, PhD: Absolutely. I think particularly for our brachial plexus patients, that's imperative to make that decision about are we going to graft an area. If there's electrical conductivity through it, obviously the patient has done the job and is healed, it just hasn't reached the muscle yet, so wouldn't intervene upon those. And re-utilizing, do you want to talk about stimulation for nerve injuries?

Dennis Kao, MD: Yeah, so I guess sometimes we do inter-op stimulations prior to neurolysis or exploration. And then-

Glen Stevens, DO, PhD: Tell us what neurolysis means. I mean, I know of course, but for our audience.

Dennis Kao, MD: So due to trauma or previous radiation, scar tissue can potentially form around the nerve and cause nerve compression and if the compression is enough, it can block conductivity or even lead to muscle atrophy. So neurolysis just means to surgically release a compression around the nerve. So we do that. And then also there are newer handheld devices, single-use devices that we can use to stimulate each nerve fascicles during surgery to help us figure out whether this nerve fascicle is working or not. And in some nerve transfer surgeries, that's what we used to determine what's an appropriate donor for us to transfer that functional nerve into a non-functional muscle.

Glen Stevens, DO, PhD: Yeah, I remember back it was always a big exam question in terms of someone had previous radiation therapy into the brachial plexus. What's the most common EMG finding that you see that will help you define, hey, it's really a radiation, or is there a tumor that's there that could be causing that type of problem? And of course, radiation-induced surgical options would be a little less, unless again, things were very scarred down and you went and were able to release something. But I assume that would, do you ever do surgery on post-radiation? It would seem a very complicated situation to get into.

Megan Jack, MD, PhD: It's very limited, unfortunately. I think the outcomes for that are very challenging because like you said, it is a scarring issue and that's the body's way of healing. And so ultimately it scars down even further with surgery.

Dennis Kao, MD: I think some people have tried, but nobody has reported good outcome yet.

Glen Stevens, DO, PhD: So, you mentioned a little bit about shoulder versus hand and the distance of the nerve. We talked a little bit about avulsions. Can we do anything for avulsions or do you just do some sort of muscle transposition to try and get some other muscle to just elevate the arm or something? But can you do anything with the nerve? If it's avulsed, the root is avulsed?

Dennis Kao, MD: Yeah. So it depends on how many roots are avulsed. So if all five roots are avulsed from the brachial plexus, then you don't have a lot of options on that side. But if you only have one or two root avulsions, you can use sort of the quote-unquote "extra", I guess disposable nerves from that side and reroute it into the nonfunctional nerves to provide some function.

Megan Jack, MD, PhD: Yes. Some more common ones would be like spinal accessory we have available as a donor, we have intercostals as a donor, occasionally long thoracic.

Glen Stevens, DO, PhD: And timeline? I have a motorcycle accident, I have also nerve root. I come to you, you say I could do surgery. When do you do the surgery? I mean, is this something that has to happen yesterday? Do you have to wait a month? Do you have to wait three months?

Dennis Kao, MD: So, if we know for sure that it's avulsed, then you don't really need to wait because it's never going to recover. But if you have, sometimes we would wait, give it two or three months, repeat another EMG to see if there's signs of improvement or reinnervation. And then usually if by six or nine months we don't see any evidence of reinnervation or improvement, we typically try to do surgery prior to 12 months.

Glen Stevens, DO, PhD: And growth rate of a nerve if you do some grafting is what?

Megan Jack, MD, PhD: It's about a millimeter a day.

Glen Stevens, DO, PhD: That's what I thought it was.

Megan Jack, MD, PhD: So, it's pretty-

Dennis Kao, MD: Slow.

Megan Jack, MD, PhD: ... slow. And you have to imagine if you're going all the way to even the forearm, that's a substantial amount of time. So we get to have a very long relationship with our patients. We follow them. We have patients that we followed for many years.

Glen Stevens, DO, PhD: And if you use one of these intercostals, is one nerve better than another nerve?

Megan Jack, MD, PhD: There are differences. Yeah, absolutely. So part of that is related to the motor content within that nerve. And also it goes back to the patient's age, the ability to learn the transfer, because you can imagine learning to take a breath while you're trying to move your biceps can be rather challenging.

Glen Stevens, DO, PhD: That would be complicated.

Megan Jack, MD, PhD: So, the plasticity of the brain also likely plays a role. I think those are some areas for research in the future to better understand how do patients integrate that new nerve transfer to ultimately have successful outcomes?

Glen Stevens, DO, PhD: Well, I guess this is the benefit of having a team and you have more than one person is that you can then toss it off and say, "Hey, what sounds like the best idea?"

Megan Jack, MD, PhD: Exactly.

Glen Stevens, DO, PhD: If you're only a team of one, it's-

Megan Jack, MD, PhD: Yeah, no, I think that's the best part is having a multidisciplinary clinic is that the patients really get to hear us talk about their disease and come at it and we sort of make decisions and they're also involved with that decision about what do we think the best option is for them and they get to help make that decision with us.

Glen Stevens, DO, PhD: You mentioned the use of stimulation during the surgery. I guess I just don't quite remember enough of the anatomy of it, but how many fascicles are there that are there that you would have to know that you're affecting or you would have to suture together?

Dennis Kao, MD: It becomes more applicable when we do distal nerve transfers. So distal nerve transfer is a relatively new technique that's been probably developed within the past 20 or 30 years. So in a past when people have a brachial plexus injury, you are identifying the injury in the neck area. You're going in there to resect the neuroma and do grafting. And so the nerve regeneration will have to start from neck and then regenerate all the way down to your target muscle. But if you have other functional nerves, for example, for the biceps, if you have no biceps function and due to a C6 injury in the past you would have to repair C6. But now people can actually take a fascicle from the ulnar nerve or a median nerve, which may still be functional and then reroute it into the biceps. But the area of the transfer is closer to the elbow, so much closer to the target muscle itself. So the regeneration time is much shorter.

What that means is you can reinnevate the muscle much faster than before. So you have less muscle atrophy. When we do those kind of surgeries, you have to go into the median nerve and you have to pick out which fascicle you want to harvest. That's when we do the very specific stimulation to see which one has more motor function. Because for median nerve you can have a sensory fascicle. If you take that, it's not going to work.

Glen Stevens, DO, PhD: So how long are these surgeries?

Dennis Kao, MD: That depends.

Megan Jack, MD, PhD: It varies. Yeah, sometimes it's a couple of hours, sometimes it's an all-day affair. So eight plus hours.

Glen Stevens, DO, PhD: Now I am not going to remember this correctly at all, so you may have no idea what I'm talking about, but I heard someone give a talk a few years ago about peripheral nerve injury. And my recollection was that instead of grafting the ends together, they were wrapping it in something and I can't remember what that was. And this allowed the nerves to end up actually growing towards each other and forming a graft. Have you ever heard of this or am I involved with something that I know nothing about?

Megan Jack, MD, PhD: No, no. You got it correct. But it's controversial in our field. So wrapping nerves is challenging. So there's different conduits that different companies make that sometimes they're made of collagen, but they're typically proprietary.

Glen Stevens, DO, PhD: It just provides a nutrient environment, doesn't it? That-

Megan Jack, MD, PhD: Theoretically.

Dennis Kao, MD: But essentially the wrap, it guides the regenerating nerve to go to the target. So you can either do that by suturing the nerve to make sure it stays in that direction or put it in a tube and just force it to go along the path of the tube.

Megan Jack, MD, PhD: Getting the two ends close enough together that the nerve will grow.

Dennis Kao, MD: Yeah, the nerve is pretty smart-

Megan Jack, MD, PhD: Yeah, they are very smart.

Dennis Kao, MD: ... finding their target.

Glen Stevens, DO, PhD: Yeah, whether I guess it's a good thing or a bad thing. It was just a bit fascinating to me that you could sort of do this, right? That it would just sort of work its way over-

Megan Jack, MD, PhD: Absolutely.

Glen Stevens, DO, PhD: ... to where it needed to go. It sounded almost too easy. I'm sure it's-

Megan Jack, MD, PhD: The nerves make us look good.

Glen Stevens, DO, PhD: ... very complicated as it goes through. Are we doing this at all or we don't believe that the technology's at a point yet that we're doing that here?

Megan Jack, MD, PhD: I think we have mixed results at this point in time. So I think microsurgical suturing is the technique that we use the most. There are, again, new agents on the field that sort of bring the nerves together, whether that's a wrap, whether that's kind of like teeny tiny little hooks that go into the nerve to pull things together, or sometimes we use glue. So there's various different techniques. I don't think we have great data to suggest one's better than the other yet.

Glen Stevens, DO, PhD: So independent of just using a microsurgical technique to put things together, is there anything that we can, nutrient wise, that we can put in the milieu around it that's helpful otherwise? Or again, this is not something that's-

Megan Jack, MD, PhD: Not something that's for prime time yet. I think there's a lot of different research ongoing, whether that's putting different types of cells in different conduits, so like Schwann cells or things that help nerve growth factors or things of that nature. But nothing that is marketable as of yet.

Glen Stevens, DO, PhD: And I assume that you're working quite a lot with physical therapists, occupational therapists?

Megan Jack, MD, PhD: We do.

Dennis Kao, MD: Yes.

Glen Stevens, DO, PhD: Do you have dedicated folks within your program?

Megan Jack, MD, PhD: We do. So we have dedicated hand therapists that are primarily focused on the upper extremity injuries and really focused on that nerve re-education afterwards, particularly if we do a nerve transfer to learn how to drive the new transfer. So if we're taking a nerve that typically goes to the wrist and allows wrist bending and we've moved it to elbow bending, a patient has to relearn how to do that. So they're dedicated for that.

Glen Stevens, DO, PhD: Now do you have a separate lumbar plexus group or it's the same looking group?

Megan Jack, MD, PhD: Yeah, correct. Well, that's more PT than OT, but yeah, no, lumbar plexus is even more challenging. Lower extremity nerve transfers are definitely not as successful as nerve transfers of the upper extremity. So we're just kind of starting at the baseline with that about what's the best way to treat those kind of patients because it's very challenging.

Glen Stevens, DO, PhD: The ideal injury to treat is what? Not that anything's ideal, but if someone-

Megan Jack, MD, PhD: One that the patient's going to recover on their own, they will almost always do a better job than we can get surgically. So if it's not a severe injury and they can recover pretty quickly over the course of the first few months, if we can see them improving their function, that's probably the best way to do that.

Glen Stevens, DO, PhD: And Dennis, you mentioned a little bit about sensory nerves. Do you ever transpose sensory nerves or it's purely motor?

Dennis Kao, MD: We do do sensory nerve transfers if the patient really wants it.

Glen Stevens, DO, PhD: And how does that work out?

Dennis Kao, MD: I would say most patients would get some recovery, but cortical re-education becomes quite challenging. If they are younger, I think the outcome tends to be better because then the brain can make the switch. But as people age and it's less adaptable, then sometimes it may work, but they don't like it. For example, for hand surgery, the pinching surface are very important. So especially between the radial aspect of the index finger and then the ulnar aspect of the thumb. So if they lost sensation on the radial aspect, you can actually transfer the nerve on the ulnar side to the radial side-

Glen Stevens, DO, PhD: Just over the other side, and then they could pinch or-

Megan Jack, MD, PhD: Feel a little bit better.

Dennis Kao, MD: But then sometimes when it's working, when they pinch, they feel like the thing is-

Glen Stevens, DO, PhD: On the other side-

Dennis Kao, MD: ... touching their other side.

Glen Stevens, DO, PhD: Yeah, that would be a really strange thing.

Dennis Kao, MD: And they hate it. So if they can't make the switch, sometimes they feel like the surgery, it's working, they can feel they are touching something, it just doesn't feel right.

Megan Jack, MD, PhD: I think the good news about sensory is there's less rush for us. Sensory can recover even sometimes we think many years after an injury, whereas motor, we're pretty much trapped for about a year when-

Glen Stevens, DO, PhD: Yeah, I guess that's the other important thing I need to ask you is what's the end point of we shouldn't be doing this?

Megan Jack, MD, PhD: Yeah, we typically say it's challenging because we don't know a hundred percent for each patient, but we typically say we like to do surgery before a year, and typically the most optimal time is three to six months often. We definitely probably would not offer any surgery after 18 months for a motor injury. We just know that the end plates of the muscle just will not recover even despite getting a nerve to grow there.

Dennis Kao, MD: But I guess part of that also depends on what function we are trying to get back.

Megan Jack, MD, PhD: Sure.

Dennis Kao, MD: So, the few exceptions that we offer surgery, even two or three years are from their injuries. I think the most successful one would be for elbow flexion because then even though their biceps and their brachialis has atrophied, it is technically possible for us to take a fresh muscle from their leg and transfer it to the arm and make it work if we can find a good donor nerve to drive that muscle. But because we are transferring a big bulky muscle, so I guess it works better when you're just replacing a single motion for elbow flexion or extension. But when you try to replace intrinsic hand function, which may take eight or 10 muscles or the shoulder, which may require four different vectors, it's very difficult to reconstruct.

Glen Stevens, DO, PhD: Need an engineering degree.

Megan Jack, MD, PhD: Pretty much. The type of injury is also important too. Spinal cord injury, we can often intervene years later, but a ligature brachial plexus injury within a year is optimal.

Glen Stevens, DO, PhD: Is there any cadaver use of nerves, or no?

Megan Jack, MD, PhD: There are companies out there that have them. I think it's really, probably the data suggests it's much better for sensory nerves. I think most of us would not really utilize it in a mixed motor nerve. We think the outcomes are probably not as good. So typically that's where we would utilize a sensory nerve donor from the patient. The sural nerve would be the most common one that we use.

Glen Stevens, DO, PhD: And we also hear a lot of organ transplants or things that are potentially possible from other species, any other species that we could get a nerve from?

Megan Jack, MD, PhD: Not on the market that we've used. So nerves can be rejected. So I know that Schwann cells are very immunogenic, so that would be the concern too. Even the graphs that we use from cadavers, they basically have cleaned out all of the cells. So they're basically just a scaffolding for a nerve to grow through. So they don't even really have any of the quote unquote "nerve cells" or functional cells in it.

Glen Stevens, DO, PhD: Any notable research going on here or elsewhere in the field? Where's the field going?

Megan Jack, MD, PhD: Yeah, I think there's a bunch of different research that's going on. We're primarily looking at just our patients and trying to monitor what are the best transfers and what are the best outcomes for the types of surgeries that we're doing. I think the field is kind of, like Dennis mentioned, talking about stimulation. I think that's probably the best option we've had to improve nerve regeneration that we've seen in a while. And so utilizing that intraoperatively and trying to come up with the best mechanism to do that is I think where the field is at right at this point in time.

Glen Stevens, DO, PhD: Any final takeaways for our listeners? Things we haven't covered that you feel are important?

Dennis Kao, MD: I would say it's always best to refer early if you're uncertain, because then that way we can at least review the patient chart. And the worst thing would be they come in and we said, "Oh, we'll see you in three months, we'll recheck you." But it's much better for us to see them early and refer them to get the appropriate testings. And rather than seeing them late and saying, "Well, we should've seen you six months ago."

Megan Jack, MD, PhD: I agree. I think our field's constantly changing and we're getting new and better surgeries, and we have a lot of different, through our multidisciplinary clinic, we have a bunch of different specialists in each of their own fields, and so we really come at it with what's the best option for that patient. And so referring them early, giving them the best option to have, whether that be nerve surgery or whether that be secondary kind of reconstruction, I think it's important to not say, "Oh, it'll get better in a year." We really do have better options for our patients-

Dennis Kao, MD: It's just neuropraxia.

Megan Jack, MD, PhD: ... Brachius neuropraxia. So I think send them on, give them the best option to get their arm back and then ultimately their life back. It is life-changing.

Glen Stevens, DO, PhD: Yeah. I think certainly in the field that I'm in, clear expectations of what risks are and what potential benefits are really what's most important for patients. Because if their expectation is different than the likely outcome, no matter what happens, they're going to be unhappy. So I think that we just need to be very clear with what our expectations are and what we expect is going to happen with the patient.

Megan Jack, MD, PhD: I think that's half of what our clinic is, is talking about what's the reality of the function you're going to get back. It's not perfection.

Glen Stevens, DO, PhD: And then they have to decide do they want to go through it?

Megan Jack, MD, PhD: Sure. Absolutely. Because they're oftentimes big surgeries.

Glen Stevens, DO, PhD: Yeah. So Megan and Dennis, thank you for taking the time to talk to us today and share your success and all the great things you're doing. I love the multidisciplinary approach that you've achieved and look forward to your continued work in this area. Thank you.

Megan Jack, MD, PhD: Thank you.

Dennis Kao, MD: Thank you for having us.

Closing: This concludes this episode of Neuro Pathways. You can find additional podcast episodes on our website, clevelandclinic.org/neuropodcast, or subscribe to the podcast on iTunes, Google Play, Spotify, or wherever you get your podcasts. And don't forget, you can access real-time updates from experts in Cleveland Clinic's Neurological Institute on our Consult QD website. That's @CleClinicMD, all one word. And thank you for listening.