Chuck and Chris on the Radial Nerve. Part II Nerve Transfers

Season 3, Episode 47.  Chuck and Chris  continue with this 4 part segment on radial nerve injuries.  In this podcast, we discuss nerve transfers as treatment for the radial nerve injury.  We plan additional episodes on tendon transfer and therapy in this series.

References:
Ray WZ, Mackinnon SE. Clinical outcomes following median to radial nerve transfers. J Hand Surg Am. 2011 Feb;36(2):201-8. doi: 10.1016/j.jhsa.2010.09.034. Epub 2010 Dec 18. PMID: 21168979; PMCID: PMC3031762.

Bertelli JA. Nerve Versus Tendon Transfer for Radial Nerve Paralysis Reconstruction. J Hand Surg Am. 2020 May;45(5):418-426. doi: 10.1016/j.jhsa.2019.12.009. Epub 2020 Feb 21. PMID: 32093993.

Subscribe to our newsletter:  https://wustl.us6.list-manage.com/subscribe?u=c6fe13919f69cbe248767c4e8&id=10e0c1dd85

See http://www.practicelink.com for more information from our partner on job search and career opportunities.
 
Please complete NEW Survey: https://forms.office.com/Pages/ResponsePage.aspx?id=taPMTM1xbU6XS02b65bG1s4ZpoRI9wlPhXnSF2MnEXxURVRNVDNBMEVSMU1CWFpIQVA4SEtMTFcyMS4u

As always, thanks to @iampetermartin for the amazing introduction and conclusion music.

Listings at theupperhandpodcast.wustl.edu.  

Transcript

Charles Goldfarb: 0:03

Welcome to the upper hand podcast where Chuck and Chris talk Hand Surgery.

Chris Dy: 0:07

We are two hand surgeons at Washington University in St. Louis here to talk about all things hand surgery related from technical to personal.

Charles Goldfarb: 0:15

Please subscribe wherever you get your podcasts.

Chris Dy: 0:18

And thank you in advance for leaving a review and leaving a rating wherever you get your podcast.

Charles Goldfarb: 0:24

Oh, hey, Chris.

Chris Dy: 0:25

Hey, Chuck, how are you?

Charles Goldfarb: 0:27

I'm really good. I'm glad to be back at it with you're talking about your favorite subject.

Chris Dy: 0:31

You know, I do like nerve. Guilty as charged. And I can't believe I've dragged you into another three part, maybe four part series about nerves. And we're in the middle of our radial nerve series. So are you enjoying it so far?

Charles Goldfarb: 0:44

I'm enjoying every second of it. And I think it's great. So today we're going to talk about nerve transfers, specifically radial nerve transfers, which I think for the audience will be helpful. Many of us know a bit more about transfers for dealing with other areas and radial nerves, I believe seem a little newer. And then we're going to talk about tenant transfers, where I can contribute a little bit more. And then Macy has agreed and is excited about talking about therapy after tendon or nerve transfers.

Chris Dy: 1:16

Great. Well, I see that Macy took the Reply tactic as opposed to the Reply All tactic in terms of our inquiry. So I'm excited. I didn't know if he had agreed or not, she always does, it's just a matter of finding the time. So I mean, before we jump into nerve transfers, I mean, what do you what do you think the role is of you know, exploring nerves. We talked a little bit about that earlier in the last episode about you know, in the setting of something that occurs potentially I energetically and there's a question of whether there was intact but do you think that there's a role for nerve exploration and grafting? You know, that was something that before nerve transfers came up and you know, is isn't wasn't an option before tenant transfers?

Charles Goldfarb: 1:55

Yes, I have to make an editorial comment before I jump into that when you talk about Reply All I don't know about you well one of my pet peeves are needless Reply All and there's like 100 people on the email and I seem to be getting those regularly and it is certain people that do it. So I know it's not you I hope it's never me. Anyways, I had to get that off my chest

Chris Dy: 2:17

there were three people on the email I don't think that's not that one. I'm happy I'm happy to not have a happy to have less email that's fine with me as long as the job gets done

Charles Goldfarb: 2:29

I mean, the ones it's like have a good Thanksgiving or whatever and then like all of a sudden everyone's saying 200 Anyways, okay backup,

Chris Dy: 2:36

but before we get into that, I have started to use the tactic of the BCC for large groups which neutralizes the reply all having people

Charles Goldfarb: 2:46

Proactive. I you know, one of the one of the things I enjoy most and have seen really good results with is the autographed for radial nerve injury, whether that be ballistic I androgenic, or or just sharp laceration. I think the the at the autographs into positional cable grabbed can be really effective. I think it's for the reasons you mentioned. And on our first episode is the distance required for the nerves recover to start regenerating muscle is shorter, but I liked that procedure.

Chris Dy: 3:28

Yeah, and I think physiologically, it makes a lot of sense why that works better than for median and owner. You know, and I think that, you know, that surgery is probably one that is not done as much as it used to be, and it probably should continue to be done, the person who would be doing that surgery is probably not the person who's considering nerve transfers. That being said, doing neurotransmitters does get you closer to target. But if the nerve train, if you are, depending on where you are with your injury, you may not be able to restore things like wrist extension fully with the nerve transfer. And you can see that many of the people that are doing nerve transfers are also combining it with a PTCRB tendon transfer at the same time, which I think is a very reasonable and appropriate thing to do. And you can also plug into the ecrb nerve. But you're not going to get the ecrl there because we know that that integration tends to come in higher up sometimes even above the elbow. In terms of where it comes off the radial nerve, I think the hard part about the nerve grafting bit is that you really don't know how much to cut out and where to cut it out. So you're going a lot based on look and feel and a lot of dogmatic kind of stuff. So that's what makes a very tough decision, because

Charles Goldfarb: 4:33

I have two questions. The first is I'd like you to talk about how the graft versus autographed in this situation and we'll paint a picture of a 45 year old male with a gunshot wound injury to his radial nerve which occurred, I don't know six weeks ago. So that's one question autographed for sale grip and talk about positioning on the table. If you favor an autograph to kind of how you think about that and what you do with it positioning the lower extremities.

Chris Dy: 5:02

So I have bias I tend not to use. I mean, I don't use aloe graph for mixed or motor nerves. There probably is some stones being thrown at me from some colleagues across the country. But I don't think the data is there. I know that there are some papers that are published, I don't think they're the highest quality evidence. And I will leave it by stating that I think there's a lot of bias in what goes into that database, but it is prospectively collected, I get it I understand Allah graft is a convenient choice. And a good choice in a lot of situations. For me, I'm not using it for mixed or motor I get that other people do. So that that's the first question for me, it's autographed. And then to the second question for positioning, I like doing this kind of case, if we're going to do an autographed in the lateral position. With either, you know, on a bump in the arm, the effected arm hanging over the bump, or on an arm holder, and that gives you access to the, to the ipsilateral lower extremity for harnessing your nerve in a position that's not going to give you cervicalgia

Charles Goldfarb: 6:05

I learned a new word. Cervicalgia

Chris Dy: 6:09

But it's, it's in the old ICD 9 and 10. I promise.

Charles Goldfarb: 6:14

I don't want it, I know that I don't want it. I like the positioning, though. And you know, and for other nerves, like you're doing a median nerve auto graft, that kind of supine position and gets really tough. I think for the radial nerve, it is easier because lateral is just a simpler approach.

Chris Dy: 6:29

Yeah, cuz I mean, honestly, even if you're doing say, for example, humeral shaft fracture, or just us fracture, many people will position a lateral position anyway, just because it is easier to get to where you need to go on the humerus and on to the nerve. Now, if you're trying to combine nerve grafting and nerve transfers, which I have done in, I think one or two patients, what I've done there is this position of initially in that position, but also told the our staff that we're going to then deflate the beanbag and roll out into a supine position with a hand table. But the hand table obviously isn't there to start for the nerve transfer part of it. The other thing you can do for exploration, if you're not going to be if you're not anticipating a nerve graft, and you're just trying to normalize is to do it supine, but take one of the arm holders that you you or one of your colleagues would use for like a shoulder scope case, put it on the opposite side of the table and use that as to hold the arm across the chest, I found that pretty helpful for this kind of exposure, as well as even for like a triceps accent or nerve transfer, if you want to just want to stay supine, and you don't want to go prone, for example, if you don't like going prone, patient can't go prone, or you think you might have to do some work from anterior as well.

Charles Goldfarb: 7:40

Good, good suggestions. All, I'll say that. To put it back to sports a little bit, I do a lot of elbow arthroscopy, and will often combined procedures. And when doing so I will do a lot of different things through that in that lateral decubitus position over an arm holder. And one of them is transpose the ulnar nerve. And, and certainly the anatomy is different. The precautions are different. But you can you can get it done and done safely and done well and done expeditiously. But it is a little bit of an acquired skill. To get comfortable with the different positioning.

Chris Dy: 8:20

I've had to do that, especially when helping colleagues who are already in the bar and going to do other things. And there's nothing like doing one of your favorite surgeries upside down. That's exactly right. All right, keeps it keeps you on your toes for sure. And the last thing, the last thing I could add is that I haven't done this yet. But one thing I learned on my visit to the Mayo Clinic is that I think it's for the for the spider arm holder set, they actually have a leg attachment to hold the leg for several harvesting, if you are so inclined, you're doing that in a supine position. I have not found that set yet. I haven't needed it yet. But that's a good thing to keep in mind.

Charles Goldfarb: 8:57

I'm old school, I usually hold the leg for somebody else to harvest. But I like that there's solutions to these challenges. All right, so talk to me about your personal indications for radial nerve transfers.

Chris Dy: 9:14

So I think that it's got to be like many nerve transfer things. It's got to be the right patient, somebody who is willing to put in the time, knowing that it's going to take probably nine months for the lights to come on at least to start to see some renovation in after a nerve transfer. And then probably 12 months to really see what kind of you know, response or reiteration they're gonna get and it seems to seem mature. So it is a big time investment. For you know, I think a functional outcome that can be fantastic. I mean, I saw a patient back in clinic on Monday, who was 15 months out, you cannot tell the difference between the suicides. I mean, it's amazing. So huge, huge upside. But, you know, it's a very long time to wait and you have to have the calculus of factors that is favorable to nerve regeneration. So a young patient typically is better. a nonsmoker, somebody who is generally healthier, and somebody who has the willingness, the personality and the resources to go to therapy. And not only to go to therapy, but to also do the exercises at home. Now, that collection of factors does not often come together in one particular patient, and you're lucky if you get most of them. But that's the biggest thing, then the injury itself has to be amenable to it musculotendinous needs to be in good shape can't be tons of trauma, and that area obviously has to have good donors. So, typical suite of neurotransmitters for this would be for medium to radio, would classically describe the Dr. McKinnon was fcr to pi n and FDS to ecrb. Dr. Patel, he does things a little bit different. But when he does it, he also typically now I believe, will add the the AI N PQ branch the distal as he calls it and transfer that directly into deep portion of the pi n, which is essentially going to the first compartment right as opposed to the finger extensors this one targeting the thumb.

Charles Goldfarb: 11:10

Nice.

Chris Dy: 11:11

Well, hey, before we get any further, we should talk about our friends over practice link

Charles Goldfarb: 11:16

Absolutely. The upper hand is sponsored by practice link.com, the most widely used physician job search and career advancement resource.

Chris Dy: 11:25

Becoming a physician is hard. But finding the right job does not have to be joined practice like for free today@www.practicing.com.

Charles Goldfarb: 11:35

Talk to me about two different things one, when you would consider adding that pronator, Teres ecrb splinting transfer in this situation. And then two, let's talk a little bit about technical for your preferred transfers.

Chris Dy: 11:51

Sure, I, I tend to follow Dr. McKinnon's advice, because I think it's a good one to add the tenant transfer at the same time because you're not going to want to go back typically, because to do that, and then transfer you will be in the area where you're close enough to where you've done your nerve transfers, where it's gonna affect your willingness to go back and do what is a very solid and reliable tenant transfer the PT to Ecrb or ecrl, wherever you want to put it, you tend to weave it into the side. And patients do like having that internal splint. And hopefully, whatever you get from the nerve transfer will augment that. I think that, you know, one consideration that needs to be stated is that one of the reasons why people don't do nerve transfers, is because they have concerns about sacrificing a future donor. So you know, if you, you know, you're already doing your PT to ECRB tenant transfer that so that's good if you're doing it at the same time, but then you don't want to lose innovation to your fcr. If you want to do that for an EDC tenant transfer, or some people use FCU, that's clearly not going to be affected here and your overall reflection power may decrease. And then you don't want to affect too much of your FDS function because that can be a great donor as well. That being said, there are more redundant fast skulls and the textbook describes in terms of branches coming off to the fcr branches coming off to the FDS. And I think it is helpful, you know, as you're doing the surgery to dissect out multiple branches and make sure that you have multiple portions of the median nerve that are that are innervating, the things that you are potentially sacrificing because taking a fascicle that goes FC to fcr wanted to go FDSs is totally fine. As long as you still have another one going into it and sometimes even if you don't, but I think I think it is helpful to check.

Charles Goldfarb: 13:32

Okay, perfect. For those of you who don't live in this world, Chris is giving an incredible amount of information in a very short period of time. So I'm probably going to have to rewind the listen to this because this is not the world I live in. I live in the pronator Terry's to ecrb world, but the rest of it a little less,

Chris Dy: 13:49

and I can't wait to hear your pearls on that. Because that I think is a very, that's a hard surgery to do really well. And then to add that into a bunch of other stuff, just you know, it doesn't get the credit it deserves.

Charles Goldfarb: 13:59

One question about the PT to ECRB for you is when the nerve when the radial nerve transfers recover, I agree that you will get better wrist extension. Do you ever get wrist flexion? Back? And I'll say, I never really care about reflection, honestly, because we don't do much in reflection. But do you lose that permanently? In this patient population?

Chris Dy: 14:20

I think you do you do some because you spent so much time focusing on wrist extension. I admit, I honestly don't really ask. Because you know, for the reasons you stated, but I think there are some patients that get very focused on numbers and perfection. That that point typically our therapy colleagues have steered them towards thinking about extension more than anything else, especially if they've had a surgery intentionally for extension. And that brings me to the point that you know, you talked about indications. When I see somebody in clinic if I'm fortunate enough to have either Macy and clinic or Jamie Findyce in clinic with me or Kathy Dahm who lives in this world and understands these patients. I asked them as a colleague and I said can you go see this page? shouldn't let me know what you think. So I did that in clinic recently with Jamie, and she saw patient and I left the room saying, I want you to talk to our therapy expert, because I'm not sure which one you're gonna want to pick. And she had an answer for me as soon as I walked back in, so it was great. And we decided that patient is better off attending transfers. So I think that's a huge part of it, because they'll get a sense of patient goals, expectations, what the recovery trajectory will look like leveling with the patients. And I think that's a hugely important piece.

Charles Goldfarb: 15:29

I love that. So true. The collaboration and partnership is really important. Alright, let's talk a little technical. So we'll maybe not talk about PT to ecrb, because we can hit that in the tendon transfer, you know, segment which will follow this one. But let's talk about your other nerve transfers, just take us through them, specifically what you do and how you do it.

Chris Dy: 15:54

So you're going to rely on a nerve stimulator typically to help you. So there are couple things that go with that. So you need to ask your anesthesiologist not to give any long acting paralytics because that can affect the how well you're able to stimulate. short acting for induction totally fine should be gone by the time you are working. placement of your tourniquet, you know, tends to be that we think that tourniquet related ischemia occurs at least half an hour after the tourniquet comes up. Sometimes it can go even longer. It's actually something that we're studying right now. But you need to be very efficient as you dissect. I mean, literally like you talk about the entire plan, you tell the or like I'm going to be kind of on edge for the first 30 to 45 minutes as we're getting started. Because I need to get this these things done. I will with most trainees, I will actually write out the entire list of steps need to happen and give them a schedule in which this is going to happen. Because I prefer to do this dissection under tourniquet as much as I can. Because I think that 30 to 45 minutes under tourniquet saves me probably an extra 30 to 45 minutes if I wasn't doing anything on a tourniquet. So typically, I am the one leading the dissection in this particular scenario, I do make the curve S shaped incision that Dr. McKinnon describes the essence of it kind of depends on what I'm trying to do and where I'm trying to go. I think you can even incorporate the Bertelli addition to this transfer from anterior only although sometimes going dorsal Lola will be helpful for that. And then you know it is speed dissection. So the things you need to get out, you need to decompress and expose the media nerve, you need to get out your donors and stimulate your donors to make sure they're healthy. So that typically involves you know, decompressing those Certus getting the media nerve out getting to the FDS arch. And at that point, you'll have seen the branches coming off of the median nerve, obviously, being very careful with them, you'll have seen the AI on itself, making sure you protect that. Then you need to tag those, identify those, tag those and then you need to get to your targets. Some people go to the targets first, but you need to get to your targets to make sure they are indeed not responding. So exposing your radial nerve. I tend to use the superficial radial nerve as a guide just even though it's dissecting or distally. Coming more approximately. That's a relatively expeditious dissection to get back to the radial nerve proper, find ecrb branches coming up before the pi n comes off finding the pi n, you can dive right to the radial nerve and go to the piano I just find the SRM to be a very helpful guide doesn't take me much longer and saves my frustration.

Charles Goldfarb: 18:26

I think that's well said and I totally agree with you. I mean, I have to I don't do nerve transfers because I like to send them to you. But when I decompress the radial nerve, I tend to go dorsally now but when I go vole early, I love that approach and it's so easy to find the superficial branch and trace it back. So big S shaped volar incision and start to identify your targets and just take us through the two main focus areas for your nerve transfers.

Chris Dy: 18:56

So, in terms of the targets, you typically want something that's going to provide wrist extension. So to augment your tendon transfer so there tends to be an ecrb branch that comes off close to where the SRN and the pi n are branching, if not sometimes a trifurcation. Sometimes it comes off the SRN, sometimes it comes off the PIN and sometimes it comes in even higher up just being aware of those variations. You know, I think that the more dissections you do, the more comfortable you're identifying that branch and getting used to its size. These are things that you clearly do not want to blow through and cauterize and all that kind of stuff because you need them. And then you know so I think finding that and then finding the pi n and you know you can find some branches to the supinator that come off before the pi n gets deeper into the fat underneath the fascia. And those are helpful use in other settings that can be helpful to use for finding your PII and proper. And then I do a complete radial tunnel release. But usually I'll wait to do that decompression until I've gotten everything done that needs to be done under tourniquet in the first 30 minutes. So when I'm setting the timer, when the tourniquets going up, I ask the anesthesiologist to set it for every 10 minutes to go off so that I know, I actually will write down the time that we start the case on the drapes, so I can keep in mind and as I glanced up at the clock on the wall, I kind of know where I am. And you know, it is kind of a time trial, which part of me enjoys until I stop enjoying it. And then, but once that's done, then I take a deep breath, we can relax and then finish the case. But in terms of the median, I think finding the orientation, you know, the branches coming off, it's always good to practice that when you're doing median nerve decompressions in the forms, it's more reps with that anatomy and seeing it and then you have the benefit of having typically, you should be having a healthy donor and using your nerve stimulator to help you. Dr. McKinnon has some really nice topography maps that have been helpful to me, but it honestly it's just more kind of visual memory as the more cases you do.

Charles Goldfarb: 20:53

I love it. That's a good, that's a great overview. And what's your Do you have one or two key articles that will be helpful for those who may have done some of these but want to refresh the technique.

Chris Dy: 21:05

Right. So I think that Zach Rey And Susan McKinnon wrote the first article on this. And that's a great technique article that's in JHS. And we can put that in the show notes, I'll pull it up and send it to you. And then I think the modification that Bertelli added is very useful. And I think the rationale for that modification was that and when he studied has results, both from nerve transfers and tendon transfers, he noted that there was a lag in the thumb MP extension. So typically that the the first compartment wasn't getting reintegrated enough. And you know, so he went back to the lab as he is a great anatomist, and, you know, looked at the branching pattern. And it's been described before, but there tends to be a component of the pi n f on the dorsal side that splits off that he called a DPI n, you know, and goes to the first compartment goes to the third compartment and then the superficial part tends to go the EDC and ECU. So that's super helpful. And then you're able to transfer directly into that into that deep branch. And the thing that reaches is the aim the same nerve, you would get first supercharged so the PQ branch, and you can actually pluck that nerve either. You can get it from dorsal if you're dorsal by working through the interosseous membrane, or you can just find it visually since you typically are that distal anyone with your dissection with the pronator teres tend to transfer and just get it vote early. And honestly, it's easier to find that vote early, you just want to make sure that you're dividing it after the FPL receives this last innovation, which typically are it's just something to think about as you're neuralyzed to get proximately to get your swing distance. These are super fun transfers, definitely something that you want to practice in the lab for so for sure.

Charles Goldfarb: 22:42

I love that I can tell the audience without a doubt, nothing will make Chris happier than getting questions about this technique. So email us at handpodcast@gmail.com Reach out to us on social media. And otherwise, I think we should wrap this one up.

Chris Dy: 22:58

Yeah, I think it'd be great to hear more about the tendon transfer part of it. So as this series comes out, if they're, it'd be great to address any listener questions and a wrap up as well. So hopefully this, this will be a fun holiday treat for all.

Charles Goldfarb: 23:12

Perfect. Take care. Thanks.

Chris Dy: 23:15

All right, you too.

Charles Goldfarb: 23:16

Hey, Chris. That was fun. Let's do it again real soon.

Chris Dy: 23:19

Sounds good. Well, be sure to check us out on Twitter a@handpodcast. Hey, Chuck, what's your Twitter handle?

Charles Goldfarb: 23:25

Mine is@congenitalhand. What about you?

Chris Dy: 23:28

Mine is @chrisdymd spelled d-y. And if you'd like to email us, you can reach us @ handpodcast@gmail.com.

Charles Goldfarb: 23:35

And remember, please subscribe wherever you get your podcast

Chris Dy: 23:39

and be sure to leave a review that helps us get the word out.

Charles Goldfarb: 23:42

Special thanks to Peter Martin for the amazing music. And remember, keep the upper hand. Come back next time