Thank you for the opportunity to be part of such an austere panel. It's really an honor to be in this group. So I was charged with discussing the technical aspects of nerve repair, which is, admittedly, a slightly broad topic. At least from my disclosure, it's research support. That's about it. But what I've kind of distilled it down to, I think you can sum it up in kind of four main points that I generally think of for any sort of nerve transfer or nerve repair. And it really comes down to these things. So I'll briefly go over each of these, although with the caveat that any of these topics could, by their own right, be an entire ICL or greater. And so I won't do them justice. But I'll try to give you some pearls and some general ways of thinking about things. And when you think about nerve repair, especially for damaged nerve and how to treat damaged nerve, I think it's important to understand that the degree of disruption of the internal architecture of the nerve is what determines the severity of injury. We're used to looking at the clinical manifestation of that injury. But when you start thinking about how is that actually manifesting inside the nerve itself, it really comes down to which part of the nerve is affected. And if you have something like a myelin injury, then they're going to have a temporary conduction block or a neuropraxic type injury. But as you start getting to more and more severe degrees of disruption within the internal portion of the nerve, you're going to have more and more deficits. And you're going to have a less reliable recovery of that nerve. So really, the kind of go, no-go for when I think about it is if the endoneurial tubes are intact, that nerve is probably going to get better. It may take time, but that nerve should recover a reasonable amount of function. And the idea is that with those endoneurial tubes intact, the axons have no other choice but to go down the right path and to regrow and to hit their targets. Once you have a loss of those endoneurial tubes, then you're going to have some disorganized repair and regeneration of that nerve. And really, in the most severe examples, you'll have this kind of scarred edge of the nerve. And that's what you really want to avoid, especially when you're starting to think about how to get a nerve transfer and get a healthy recipient nerve for that nerve transfer. So just in a graphical form, a way to think about this is as you go from left to right and up to down, myelin, up to epineurium, as you have increasing degrees of tissue damage, your chance of recovery decrease, and that's increasing grades of nerve injury. And if you think of this more on kind of a microscopic level, this is from a study where they did a rapid stretch entry to a nerve in a rat model and then looked at what was damaged. And they stained the different parts of the nerve for endoneurium, perineurium, and epineurium. And this is out of Utah. And it's interesting. The sham is on the left, and so that's a totally healthy nerve. But then you start looking at how the nerve is organized as you go into increasing degrees of disruption. And it's important, and what I like about this is thinking about the idea of elastic, inelastic, and rupture, that the zone. We always talk about zone of injury, but it's kind of this amorphous thing. And if you think about it more as an elastic or inelastic stretch injury, the elastic injury has less of a disruption, and you might actually be able to get away with repair of that nerve. And inelastic are certainly a rupture. The endoneurial tubes, as you can see there, are highly disorganized, and that nerve is not going to recover. So you want to be further to the left than you are to the right to have any option for possible recovery. And what it really comes down to is what we do clinically, as you see on the left, and that's what we think about and talk about a lot. But ultimately, that's going to affect what's happening from a mechanistic level for the nerve. And I love this diagram from, it's an old diagram, but really shows the regeneration and all these things that are happening on a much more microscopic level. And so how do we set ourselves up to get that best regeneration and the best chance of that nerve transfer successfully going into our recipient nerve? And it is that you need respect to healthy extruding fascicles, that that nerve needs to look like that picture on the bottom left. You have to have this pooching, and that tells us that the internal neural pressure is enough that it's pushing out those fascicles, and those fascicles aren't tethered at all, such that they're able to kind of glide and be pushed out. And then you know that you're back to a healthy nerve. You can also use other context clues, such as the surrounding epineurium, these bands of Fontana, as they are. But ultimately, the key is get back to healthy nerve when you're going to transfer a good nerve into it. So get out of the zone is the first lesson. The second, no tension. Now, hopefully, with the nerve transfer, you have enough redundancy for the recipient nerve and the donor nerve that this is really not an issue. Occasionally, you might find that you run into, somehow, one of the healthy donor or the recipient was somehow compromised, and you've got more of an option. But in the perfect situation, you want to have a direct, tension-free coaptation. Good, healthy nerve to good, healthy nerve. Whether or not you do an epineural or group fascicular repair is really up for discussion. It probably depends on exactly which nerve you're doing. I think the standard for most people is the epineural repair, but there may be isolated incidents where you have a specific motor or sensory branch that you're trying to transfer directly. And the idea that you want to avoid tension is a very old one. So this is an old study that looked at increasing defects in a sciatic nerve repair model. And then they looked at what the effect of the tension was. And the take-home point for these graphs, which aren't perfect, is that severe tension really led to no recovery in this. And then a more recent study that looked at the functional recovery with degrees of increasing defect size for a nerve resection model, they're actually able to quantify the effect of increasing size of the defect on the tension. And what's interesting about the graph on the left is that if you look at a 3 millimeter repair compared to a 9 millimeter defect, which is pretty big in a rat sciatic nerve, that it's essentially almost a 6 to 7 fold, or actually 9 fold increase between those two. So substantial increases in tension with relatively marginal increases in the defect size. Interestingly enough, their axon count did not change in terms of the recovery between the groups, except for when there was a 0 millimeter defect, meaning there was a tension-free repair. What we found in a study out of our lab was that conduit splinting can actually prevent rupture of repairs under tension. And so the idea of using a conduit as a splint is that you would repair the nerve, and then you would put a conduit around it and have these detensioning sutures on either end of this. This is not a perfect technique, and I'm not advocating for this in all situations. But if you find yourself that you're in a position where you're worried that the nerve is going to pull apart, then what we saw was that if you look here on this graph on the left, that repairs that were done, this is a 5 millimeter defect, and we either repaired them with the conduit or just repaired them by themselves. And repairing with the conduit means epineural repair, and then put a detensioning conduit around it, basically. And then what we found at six weeks was that four out of the 10 had ruptured, or sorry, four out of the 10 were intact when we just did the epineural repair and no conduit detensioning, whereas nine out of the 10 were intact if we used the detensioning technique. And we had six ruptures, which is the primary repair without a conduit. So what this taught us is that if you're worried about it, a detensioning kind of conduit-assisted repair may actually help prevent a rupture of a nerve. So it's something to keep in mind. Ultimately, though, if you can get a nerve together by neural lysing, by bending the elbow, by bending the nearby joint, all those sorts of things, that will give you your best result compared to a reversed isograft in this rat model, and even compared to a conduit splinting under tension. So get a primary repair if you can. There's a sweet spot between a little bit of tension versus having to use an allograft. Suture numbers, if you put more sutures in around your nerve, you will increase the tensile strength. This is a biomechanical study that looked at the load for just repairing with different numbers of sutures around the nerve, and as expected, if you have more sutures, then it takes more to pull the nerve apart. What was interesting is that fiber and glue did not substantially increase the pull-out strength for any of these constructs. Fiber and glue by itself had some ability to prevent failure load, but fiber and glue combined with suture added a little bit, but nothing substantial. So you have to be careful relying just on fiber and glue, although interestingly enough, there was a recent randomized controlled trial looking at major mixed motor nerve repairs with autologous fiber and glue, and they found pretty similar recovery between the sutured repairs in the black and then the fiber and glue in the gray, and that is the motor recovery is on the left and sensory recovery is on the right. So my personal preference is I use sutures and I reinforce with fiber and glue, but there is a trade-off. The more sutures you use, you're also at risk of causing an inflammatory reaction, which can also be detrimental. So all things in moderation is the take-home point for that. So if you're avoiding tension, then we have to think about how are we actually gonna physically put the nerve together to line up the fascicles, and with a direct nerve repair, the fascicular topography can become quite important. Having an understanding of that and being able to match the alignment of the nerve is important and useful. In a nerve transfer, that's really not usually an option, so this is less important for what we're talking about today. Some people have utilized porcine wraps as an adjunct to primary epineural repair, and that is, I think, a practice that you often hear talked about, but probably see less evidence for than you would expect, given the number of people who talk about it. This was a study out of Hopkins and Dr. Tafaha's group, and they looked at outcomes at five to 15 weeks in a median nerve model, where they transected and repaired it in a rat, and what they found really was that there was no difference in grip strength, number of axons, myelination, any of these histologic or functional outcomes when they wrapped it or they didn't wrap it. There was less intraneural collagen deposition in the wrapped group at five weeks, but that wasn't significant at the long-term follow-up of 15 weeks. In grip strength, actually, the only time they found a difference in strength was grip strength was higher when in the unwrapped group at five weeks, so this was not particularly convincing in terms of the need for an extracellular wrap around the nerve repair. Similarly, this is from Dr. Shin's group at Mayo that looked at conduit wrapping of motor nerve repairs, and they found that it did not improve outcomes in terms of force measurements or other functional outcomes when they wrapped a nerve repair versus just the nerve repair alone. They did note, however, that there was less epineural scarring around the nerve with the utilization of a wrap compared to a suture repair alone. What we found when we did a similar study is that conduit wrapping led to more debris and actually a worse sciatic functional index with the conduit wrap versus the direct repair alone. There were similar number of axons at the final follow-up, but the overall axon density was lower, although the axons were bigger. So I think, in summary, what I would say is that I don't think anybody's shown a substantial detriment to utilizing conduit wraps, but I would be cautious about their use because I don't think that we have convincing evidence quite yet that they're a necessary adjunct to a primary repair. Finally, and I won't spend too much time on this because it doesn't really apply, hopefully, for nerve transfers, but if you do have a gap, if you find yourself that you've come up short somehow in your nerve transfer and you need more length, you have a number of options. Traditionally, conduits, allograft, and autograft have all been considered options for making up gaps in nerve defects. At a case example, this is a young woman who had an ATV accident, and both bone form fracture and an avulsion injury of her ulnar nerve. We've cut back to a healthy nerve here. You can see those pooching fascicles. Now we've got a gap, and we have to deal with that. So how will we do that? Well, conduits were initially an option. I would, and there are plenty of people who are working on really fascinating things to try and augment conduits and make them better, everything from growth factors to internal matrices to help guide the growth. There are different Schwann cells, mesenchymal stem cells. There's fascinating research going on, but I think more to come on that. Nobody's kind of hit a home run quite yet. There are multiple clinical trials underway to look at conduits and how to aid in augment nerve repair with conduits in different ways. But the traditional data that we have for kind of the typical hollow conduit versus, say, an allograft is that the conduits are really probably not quite as good, particularly when you get to a larger defect. And so this looked at digital nerves, prospective randomized trial, and at 12 months there was inferior results with a conduit compared to an allograft with regards to regaining two-point discrimination. People have also then looked at, if we have allografts, that's a commonly used thing. So allografts versus autografts, because allografts have a lot of advantages in that you can avoid a donor site defect, additional surgery, and additional time. This study in JBJS from a few years back looked at a rat sciatic nerve defect and found no difference between a cellular nerve allograft and a cabled autograft in a rat sciatic nerve. And similarly, good outcomes have been reported with a cellular nerve allografts in retrospective studies utilizing industry-funded databases. I would interpret these with caution as well. I think that there certainly is a role for allograft, but you need to look and evaluate the data for yourself. This was meaningful recovery in a vast majority of patients that was reported, but most of these were relatively small defects, and most of them were sensory, few were pure motor. So I'm not trying to advocate for or against any particular option, but I think that you should read the literature carefully for yourself. There are others, Dr. McKinnon has reported some catastrophic consequences with a cellular nerve allografts that she's treated in patients in this small case series. So things to think about. And this is actually a really interesting slide or figure from that case series that looked at the recovery of a nerve with isograft or ANA. And to orient you with this figure, essentially what you really need is about 30% of motor neuron re-innervation to obtain a significant functional outcome. And so if you start to fall off this curve in terms of your number of motor neurons that finally heal, then you're in a pretty bad predicament in terms of your overall function. And what they found is that the four centimeter nerve allografts and the six centimeter nerve allografts were at this portion of the curve. Whereas a two centimeter nerve allograft actually functioned pretty well. And similar to a two centimeter, four centimeter, and a six centimeter nerve autograft. So the take home point from this is, if you have a larger defect, say more than two to three centimeters, you'll probably have a better result with a nerve autograft, according to this, as opposed to a nerve allograft. Again, something to be aware of. So sterile nerve, in my mind, is still the gold standard, but allografts are certainly an option. And I'll finish up very briefly with this case. We had this 15 year old female that we mentioned before. She had opened both bones, she was fixed. Spanning plate, and then fixed the ulna. A Volsteller nerve, we trimmed it, got it healthy. We have a big gap. And so in my mind, this person would get a cabled sterile nerve allograft because of the large size of the defect. Healthy fascicles on either side. This is a quick summary. Autograft. I'm sorry, autograft, yes, thank you. So sterile nerve autograft, not an allograft for this patient. This is an allograft. Thanks, Chris. So what should you do when? This is kind of my guidelines for myself. Take from it what you will. But smaller gaps, I think you can probably do what you want. Autograft, I reserve for usually three centimeters or less. Larger defects, I use an allograft. I'm sorry, allografts I reserve for three centimeters or less. Autografts I use for bigger defects. And then ultimately, get out of the zone of injury. Minimal tension. Line it up well. Wrap if you like or not, depending. And then try and use the appropriate graft. That's it. Thank you. So Dr. Bergen, we do have a question from the audience, but I do want to ask when you're running for office, because you towed many lines there with regards to whether to put something around your nerve coaptation and about the allograft. So I look forward to the cage match of you and Dr. Shin with regards to wrapping your nerves. So one question from the audience. Can I submit now? There's a mic next to you, if you don't mind. Thank you. Thank you. Actually, I got a couple. With respect to wraps, it seems like the word on the street, not the official, is don't ever put a wrap on it because people like you in tertiary centers have to pull those out and pull your hair out. You hear that all the time. Sure. But going to the autografts, that last slide's pretty interesting. So as a practical matter, you're dealing with a trauma like what you're dealing with, and you're hoping you can use an off-the-shelf allograft, but you realize you can't. But maybe you're in a community setting without six fellows in residence. How do you transition from that moment to taking a sural autograft exactly? Because there's soup on the table and it's not an easy thing. Yeah, no, it's a fair point. And I think that's how part of the attraction of the allografts, and we've all been in that. It's two in the morning and you don't want to go and prep the leg and add another hour to your case. And it hadn't talked to the patient ahead of time and such. I had a case a few years ago that was sent to me and the patient had ulnar nerve dysfunction after fixing a montasia fracture or election fracture dislocation. And so I went to explore her and thinking the nerve was just kind of encased in scar and the surgeon had actually cut through the nerve. And we had our outpatient ambulatory surgery center. We were not set up for like a big micro reconstruction and such. And so the temptation was to get something off the shelf, just kind of throw it in with my loops and whatever. In that case, I actually just went out and talked to the husband and said, you know, look, this is the case. And if it was me, this is what I would want for my ulnar nerve. And so this, I'm going to sew her back up and just close the wound. And then we booked her the next week and I did it at the main hospital. So I think you have to decide what you're comfortable with. I have had the time where I'll just say, I'm going to do it another time. I think for smaller defects, I think it probably doesn't matter. I think for bigger defects, if it's my nerve, I would still ask that you take my serial nerve. And it also depends on the nerve that it is, right? So I think ulnar is a little bit more important than say the superficial branch of the radial nerve, something like that. So David, question for you. Say you're having a difficult time putting a nerve together. You mentioned that there's a sweet spot for tension. What is the sweet spot and what's your current threshold to flex the joint? And how long would you keep that joint immobilized if you had a nice coaptation or would you do your fancy little conduit splint kind of thing? Or put in a graft? Sure. So some people will say, you know, use an 8-0 nylon or a 9-0 nylon as your threshold for if it breaks with that, it's too much tension. And that's a reasonable kind of proxy. If I have to flex the joint significantly just to get it to touch, then that's probably not a good, at least in my mind, not a good option because then I'll spend the next six weeks worrying if they kind of extended their wrist for a moment. If I can get it with the arm fully straight out, but it seems like it's a little bit of tension, I feel better just to help myself sleep, to put them in a little bit of flexion. I'll often do that, but I think if you truly need it to be flexed to get the nerve to touch, I don't think that's a good option. I would go to something else. All right. Thank you, David. We'll bring that panel back up. The viewing from this angle is not great, so let's go to our next speaker, Dr. Shin. Pull up your slides here. Wow, I'm surprised to see how full this room is. When I first started nerve surgery, it was because nobody else wanted to do it, and now, like, everybody wants to do it. That's amazing. So, a couple of comments for David. I've had some perineal nerves in young people where it was a blunt trauma. You take out one centimeter, and then you sit there and struggle. I could bend the knee up 45 degrees, get a primary coaptation, and then you struggle, because I know if I put a graft in there, it's going to really not do well. I have a couple of semi-professional hockey players I did that on and just said, it's never going to work, and it worked. I have people that I've done on where I said it was not going to work, and it didn't work. So, I'm still trying to struggle with that. The whole concept of conduits in our practice, and we've done close to 2,000, 2,500 brachial plexus reconstructions since 2001, is not to have the conduit there as a protector, but a lot of times we take intercostal nerves, three or four of them, and when you put them together with a muscutaneous nerve, and there's a little bit of pressure there, and you go back, all of a sudden you see it, there are four flat nerves and a round nerve. So, our first impetus for using conduits were to keep a nice round shape so that we would have all the fascicles lined up the way, and we've kind of moved to using it for almost all our reconstructions. Okay, anyway, so much for that. You can't respond, so I'm sorry. Okay, so my charge was to talk about why my nerve transfer didn't work for elbow flexion, and I was kind of looking at this, and if you look at the history of nerve transfers, we think this has been really, really new, but they've been around since 1903, and the latest and greatest thing that happened was Christoph Oberlin describing the ulnar nerve fascicle transfer, but since 1994, there really hasn't been anything new, hot, or anything like that. So, I'm waiting for some of you young surgeons out there to get something new and novel that actually works even better than what Christoph proposed to us. Now, we all know the importance of elbow flexion, and there are three things that could bend our elbow, and we have to be very, very careful to be able to discern what I call the inadvertent flexors, because patients are unbelievably good at faking us out. They will do these funky trick motions, and you'll say, yeah, that's a grade four, that's a grade five, so be careful of those trick motions. We see loss of elbow flexion in the C5 patient. This is a classic, and you lose elbow flexion, shoulder function, and FCR, and pronator, and they're always smiling and happy, just like this guy here, and see if you have a little bit of seven out, you lose a little serratus, sometimes some triceps, even though triceps is mostly eight, but you have to look about and see what the radial nerve is doing as well, and then finally, you have the absolute disaster, which I call the pan plexus, and in the pan plexus, when you get the video of them that I'm struggling to get right now, it is, I guess that's not going to work, let's see, when you get the pan plexus, this is the best video, because you get the video of them, and they're looking at you, and they're just looking at the camera, and here he is trying to move his arm, and he's just moving the arm that works, but this is the one where it's the most difficult. So the indications for nerve transfers are based on available donor nerves, an appropriate time from injury, orthopedic stability and mobility, and the relative one is age, and when we look at donor nerves, because of the push for nerve transfers, we have been pushing our indications, and we kind of say, oh, I think that nerve might be good to use, and we try to figure out what nerve we want to use, but when you do donor nerves, you want to do synergistic functions, anatomically feasible, and you want to minimize donor morbidity. Now there's a whole controversy on the ideal timing, and it's really a bummer when a patient comes to you around 11, 12 months, and you know that you could have done a nerve transfer very, very early on, and it would work unbelievable, and we have a lot of wishful thinking, and we sometimes go, yeah, you know, you're about eight, nine months, and we really like to do about six, seven months. Oh, let's try it, because it's going to be easy, and then it fails. Typically for me, when I'm in the six to nine months, especially the six-month mark, I'll say let's do it, but then when I start getting to the nine, ten, eleven months, you start getting really risky, and you got to tell that patient maybe it's not going to work. You really came in a little bit too late, and these little motor end plates can be both your friend and your enemy, and when it's late, they're your enemy. Then there's age. I call old five years older than me, and so Alan Bishop, who's my partner, is a real old effer, and I tell him that every day, and so when I look at patients, I look at them, and if they're 50, and then I go, and I add five, I go, yeah, you're really young, let's go for it, but there is a difference between physiologically young and chronologically old, and you have to look at that, because some patients come in today, and they basically could peloton the hell out of me, and basically are physiologically unbelievable shape, and I think they are different in nerve regeneration and healing than the same age person that looks like they're 200 years old, so this is a judge that you have to look at, but the data that out there that says the older you are chronologically, the worse you do. Then there's BMI. I live in the middle of the upper Midwest. There's not a lot to do in the winter except for eat cheeseburgers, and sometimes they put on a lot of weight, and what they're Sokolovsky down in in Argentina said BMI is a huge factor, but it's interesting. Some of the really, really big patients that I have, and we do these nerve transfers on, I'm blown away that they get better strength than I ever imagined, so I'm trying to understand this BMI thing right now, and I don't want to do the wrong thing for a patient, because I think their BMI is high, but I do think it has an effect. When we make our decision, it all depends on the type of injury, because a brachial plexus is not a brachial plexus is not a brachial plexus, because we call the same guy that fell out of a window eight, five to ten feet the same as the guy that goes 90 miles an hour into a brick wall, and they're both brachial plexus, so you have to understand the extent of the injury, especially soft tissues. So this is a patient that lost his biceps during his injury, and the surgeon re-innervated the musculotaneous nerve, and the question was why didn't the biceps work, and in the notes it says I did this great nerve repair to the musculotaneous nerve, and now ten months later there's no elbow flexion, and I was like, huh? There's no biceps, and so that's what you have to look at. And then the other thing is people fail because of a failure to look at the osseous injuries. As a plexus nerve surgeon, you have to be the vascular surgeon, the plastic surgeon, and the orthopedic surgeon, so if the passive range of motion is not there, or your elbow is kind of fused because of the injury, you're not going to have good elbow bending, so you need to optimize joint function prior to making the decision of whether you're going to do a nerve transfer or not. Now the nerve transfers that I use for elbow flexion could include intercostal nerves, they're a pain to harvest, they're tedious, they're meticulous, but you need to do them really, really delicately. When I was with Oberlin, he would put a little loop around that, and he would say two grams, and I'm like, what the heck is two grams? And so I tried it on a little thing, it is so delicate, and sometimes when we harvest these, we're a little too aggressive because we want to be a little faster, and we kind of don't treat them as nicely. So nerve transfers, intercostals are great, they give you good function, especially if you don't use interposition grafting. The hardest thing is they're non-intuitive. You have to hold your breath, do something funky, pretend to fart, I actually tell my patients just pretend to fart without farting, and then all of a sudden their arms move for the first time, but it's non-intuitive. So in patients with closed head injuries, they have a very difficult time engaging this, and so we're kind of getting away from intercostals to muscutaneous, but sometimes you have to use those. We found that spinal accessory to muscutaneous nerve with an interposition nerve graft, despite the interposition nerve graft, has unbelievable better control and function in the end. I mean, think about it, if I said to you, grade your shoulder shrug and go from max shoulder shrug and go half and give me a quarter, it's easy to do. If I say to you, okay now do your intercostals, give me half, I don't know what half is, all I know is an all or none. So this ability to grade the shoulder shrug and activate the muscutaneous nerve has been really, really helpful in controlling the upper extremity for patients. The Oberlin transfer is depicted here. The modification, whether you're from Susan's camp that she did it first or Christoph's camp from he did it first, I don't care whose camp you are, I was there when this came out and I was sitting at dinner. Christoph was here and Susan was here and they got up and they started talking about it and it got ugly. And so after that meeting, Christoph said to me, I'm never coming to a meeting with her and Susan said to me, I'm never coming to a meeting with him. And so that was easy, they both stopped coming. Not kidding, I mean, I was sitting there with a couple other people, we were just blown away at this unbelievable history in the making. But anyway, whatever you choose, single versus double, I think it's really important that you do it well, you tell your patient their expectations and understand it still will fail about 20% of times. And so whether you do single or whether you do double, this is a Navy patient, he had trouble with his belt so he never pulls his pants up. But I thought he was like unbelievably strong and we're gonna get back to this guy in a little bit. I thought he was a grade 5 but I'm gonna get back to him later. And then there's other transfers you can do that are quite novel and some of these are hard to do and use because of the non-intuitive way to fire them. And then there's others, you could do contralateral phrenic, we don't do these anymore, they've not worked well in our population and we're very bluntly honest, I'm no longer allowed in Shanghai because I talked against the contral C7 so I don't go there because I like life. And the phrenic nerve we stopped using because it's hard to use. So here's the main thing, why did my nerve transfer fail? Well first of all there's poor decision-making and poor surgical technique, they need to go to visit David and learn how to do this absolutely perfect. But it's funny, some surgeons I've watched put these together and they're not perfect and the patients still do great. So there's something else going on. And then there's all these patient factors that you have to look at and unfortunately there's not enough data and critical data that we could put into this AI machine and put this patient and his characteristics and spit it out where it says 82% chance of elbow flexion. But in that patient it's either all or none or a little bit. So one of the problems of nerve transfers is we use injured nerves and in this study by Andrew Lovi and Nick Poulos we looked at all our Oberlins and did a case-control study and found that we use a lot of nerves that were initially grade zeros that recovered to grade fours and then basically took a leap of faith and said yeah we're going to use them anyway. And we found that if they have no FCU or a weak FCU and that they were previously significantly injured they don't do so good. And so it makes sense if you're going to make great wine you don't take shitty grapes you take the best grapes that are there. Measuring outcomes. We are so bad at measuring outcomes and there is such bias and that bias I'm going to tell you some of ours because we did a study where we took all our elbow flexion patients and Alan Bishop, Rob Spinner and myself graded them. We put them down on paper and then we sent them to the biomechanics lab. And so right there is percentage of normal that's the red line. Okay so we said there were 12 patients with grade 5 elbow flexion and if you look there their average compared to the other side was only 40%. We sucked. And so because of this study and we also did the triceps and we did our gracilises too, we cannot get normal compared to the opposite side. So in our practice any nerve that has been repaired or reconstructed I can never give them a 5. And so that's how we're trying to be as honest and transparent as possible. So here's one of those guys that here he had a nerve transfer and we graded him a 5 and actually he was not good. So bottom line if you do nerve transfers you're going to fail. You are going to have a failure. I don't care who you are if you do enough number of these someone's going to come in with inadequate elbow bending, synergistic problems, inability to activate and they'll basically say it failed and you need to know how to deal with it. When we address failures you have to look outside the box whether it's amputation and myoelectric fitting, whether it is using a free muscle to available donor nerve or to try to find other options and this patient here is a latissimus transfer that had a bipolar latissimus. You have to figure it out and whether it's a myoelectric, whether it's another type of surgery, it's your responsibility. There are some patients you just can't do anything in and you just have to be open, honest and say I have nothing more for you and if they want to see somebody else that they want to see I encourage it because there are people that think outside the box and I love that outside the box thinking but I tell people to be realistic and if you want a miracle the church is down the street. If you want realism go to these people that I trust. Well anyway I will say that I really appreciate being here on the panel and in summary critical decision-making, careful comparison of results, understand the reasons for failure and sometimes it's us as a surgeon and understand your treatment options when you do fail. There's a great reference here Amy Moore wrote this chapter for us in our operative brachial plexus surgery and I really she has a great section on here on outcomes and what to do with them and I highly recommend that for you. Thank you very much for your time and your attention. Alex that was fantastic thank you. One question for you before we move on. You talked about trying to stay away from injured donors. Now is there still a role of for using an injured donor or what is your current threshold? I know that Jaime will check you know on he'll check on a dynamometer for his donor. I know that Scott Wolf has published about EMG characteristics in terms of motor units. What are you using now? I think it's a combination of things. I think number one you have to look at if it was completely out and some nerves that are completely out from the beginning that recover very very quickly within the first month and all sudden their grading of the ulnar nerve for example for a Oberlin transfer becomes a strength of four four plus and every time you see them they get stronger and stronger. I think that's a great indication. If they recover at six seven eight months and you can still break their wrists and their intrinsics are a little weak they have a little this yeah there's some fibers getting down there but not healthy enough for me and so I look at EMG clinical examination and I have the blessing of two really really smart guys Alan Bishop and Rob Spinner. Rob Spinner is like this neuron in a box and then Alan's kind of like this older guy that kind of go hmm and then between the two of them it's like the AI machine. I'm just a comic relief. Thank you Alex. All right so let's bring up our next speaker Brian Loffler from from Charlotte North Carolina. Well, thank you for the opportunity to speak, and it's an honor to be a part of this panel. Okay, so I'm going to talk to you about why shoulder nerve transfers may not have worked and what do I do now, and you'll see some overlap with some of the content that Alex just provided on why nerve transfers may not work for a shoulder, just like they may not work for an elbow, but I'm also going to highlight some specifics to shoulder that I think are really pertinent, things that you guys need to think about. So I'm going to review some common nerve transfers for shoulder reanimation, because they'd all end up like this gentleman here. We're talking about triceps to axillary nerve transfers, although I acknowledge thoracodorsal is another option that some may use, and spinal accessory to suprascapular nerve transfers. And one of the most important points I think I want to highlight is that we really have to consider treatment for both the axillary and suprascapular nerve, because if you have good axillary function but no suprascapular nerve function or no rotator cuff function, you're not going to have any shoulder function. If you have a weak rotator cuff and no axillary function, you're not going to have much strength at all in that shoulder. And if you have a good axillary and deltoid function but you don't have an infraspinatus or teres minor, then you're going to have good forward elevation but you'll have an external rotation lag, and we can address each of those separately. So just to review briefly what triceps to axillary nerve transfer is, this is a left shoulder that you see in the video there. We've dissected out the medial head of the triceps off the radial nerve and transferring from the triangular interval up to the quadrangular space where you see the common trunk of the axillary nerve there, and specifically into the anterior division of that. You can use longer lateral heads as well, but I tend to prefer the medial head of triceps, and that's the nerve repair that you see there. It was tension-free, David, but I also wrapped it as well and augmented it with fiber and glue. So here is an example of a spinal accessory to suprascapular nerve transfer. It can be done anteriorly, but this is from a posterior approach. So this is a left shoulder, lateral decubitus position. We've dissected out spinal accessory on the left there to where it trifurcates. We've released the transverscapular ligament and freed up the suprascapular nerve in the middle video there, and then we're going to swing those up and do tension-free neurotization, which may have the potential benefit of getting out of the zone of injury and getting us a little bit closer to the targets. So those are some theoretical benefits of potentially doing a posterior approach versus anterior. So when I think about why didn't a nerve transfer work, I try to break it down into where we can have different problems and think about it kind of algorithmically. So it could be a problem with the donor. It could be a problem with the recipient. It could be a problem with our preoperative evaluation and patient selection. It could be a problem with the surgeon or technical issues, and then some miscellaneous ones as well. And hopefully if we kind of go through all those, we can try to get a handle on why these nerve transfers didn't work. So thinking about donor problems, as we've already hit on here, if the donor is weak, that's not ideal. Sometimes that's all we have. Sometimes it's a recovering nerve, and I acknowledge there's a spectrum of recovering nerve, a quick recovering, early recovering nerve versus a late recovering nerve, and how strong it is. But we really don't know what the ultimate strength of that is going to be with its natural history. And from the Mayo study as well as Scott Wolf's study, we know that even if they have good clinical strength but they have some sort of EMG changes, that the outcomes are significantly worse actually. Even if you have donors that are all M4 and 5 clinically, you can have significantly worse strength and motion when you're transferring a nerve that has EMG changes in it. And there can be problems with the recipient. Maybe too much time has passed, you know, getting it in nine months and a year and beyond. Or maybe, as Alex showed also, you could have damage to the actual muscle that you're transferring into. You could do the best nerve transfer in the world, but if you don't have a good recipient muscle, you're not going to get good reinnervation. How about patient selection and evaluation? I think, again, we need to address all aspects of the shoulder injury. We need to address the rotator cuff. We need to address the deltoid. And we also need to look at scapular winging. Many of these patients will have a shoulder dislocation. They may have a rotator cuff tear. And it may be something that was pre-existing that they were previously compensating for, or they could have had an injury to their suprascapular nerve that gets missed. So I almost always get a shoulder MRI, preoperatively assess that. Because again, if you do a great nerve transfer to reanimate the deltoid, but you don't have a good rotator cuff, you're going to have a compromised result. And of course, we need to take the shirt off and we need to do a thorough examination for scapular winging. And then some other patient criteria. Older patients, as Alex mentioned, those are less than healthy. Or when we start getting too far out from the injury, we have to weigh the risks and benefits if it's worth it to carry out the transfer. And that may be a reason for failure. How about surgical issues? You know, I think with this particular nerve transfer, triceps to axillary nerve transfer, it's possible to not be 100% certain about what the anterior branch of the axillary nerve is. And that's really where you want to send all your axons. If you have a complete palsy, you can use an intraoperative nerve stimulator and you're not going to get any stimulation. So it might sort of feel like a guess. And I think you really want to be certain that you dissect out all the branches and you can literally follow that anterior branch going into the deltoid and make sure that you're not carrying out a transfer to the posterior branch or teres minor or superficial lateral cutaneous branch. Another technical issue is if we're not getting out of the zone of injury, as has been mentioned, if we're not transferring enough axons or if there's any tension on the transfer. Again, this is one of the reasons why I like the medial head of triceps. It has a number of axons when you have two and three branch specimens that is equivalent to the anterior branch of the axillary nerve. And you can always get the swing distance to do a tension-free neurotization. And I think especially for the shoulder, rehabbing it is more difficult. There's a little bit more required in terms of cortical plasticity and learning this. When you try to bend your elbow and you use a wrist flexor, that's pretty intuitive. That's pretty easy to figure that out. But when you're trying to get your triceps to lift your arm up, you have to think about that a bit more. And we've seen some patients who didn't have a whole lot of rehab and they didn't really even understand what they were trying to do to accomplish the goal. And going in a supine position is a great way to do that. I think with shoulder as well, maybe we haven't given it enough time. We can see reanimation of the biceps from a single or double vesicular transfer within six months. For the shoulder, I found it can take a year or more to see that clinically. Even if they have reanimation, they may not show it clinically. And there's a study from Scott Wolf's group showing that the strength actually can improve from even two to ten years out. So what do we do when the nerve transfers didn't work? And I'm also going to lump in or if they weren't performed, so if we're getting them to them in a late setting. So describe a few different scenarios here to think about this. So where we are right now, we've got to look at where we are and what we have and what to do. So if we have a strong deltoid but we have a weak rotator cuff, and clinically the patient has good flexion and abduction but they have an external rotation lag, we can do something to restore external rotation like a lower trapezius transfer. Or in a case where the spinal accessory has already been transferred, we can use a contralateral lower trapezius transfer. So this is just an example of the setup I do. This can be done open or arthroscopic. Typically do it in a lateral position. You can release the lower trapezius off the inferior border of the scapular spine and lengthen it with an Achilles graft. Then shuttle it out laterally and repair it like a rotator cuff and suture that graft to the greater tuberosity or residual infraspinatus in maximal external rotation. This is a case where the spinal accessory had already been utilized. So we use a contralateral lower trapezius origin transfer. You can take the lumbar fascia with that as well. You can also augment it and get additional length by adding an Achilles graft. And that does give patients this kind of unusual looking buffalo hump kind of thing where that muscle is tubularizing going across. But it can work well and could be a good option to restore external rotation. Think about shoulder arthroplasty. If you have a strong deltoid but no rotator cuff, you actually can do a reverse total shoulder arthroplasty which does not require any rotator cuff function in order to achieve abduction. And you may or may not add a lower trapezius or latissimus transfer if you're trying to get external rotation as well. So I'll show quickly a case of a gentleman who had a shoulder dislocation. He had a rotator cuff repair. The axillary nerve injury was unrecognized at six months. Not only had the rotator cuff repair failed, but he also had the axillary nerve palsy with complete atrophy and essentially no shoulder function, EMG showing no re-innervation. So a revision rotator cuff repair was performed. I was able to repair the infraspinatus and also do a triceps to axillary nerve transfer. But clinically, he really wasn't getting anything back. Even though our EMG showed that the deltoid was getting re-innervated, clinically we could see that the deltoid was contracting. He could still only forward elevate about 40 degrees. And so I waited until about 18 months to see what the max he was going to get. And then with that re-innervated deltoid, we were able to do a reverse total shoulder arthroplasty. And at first I was like, I don't know how quickly this is going to recover. Six weeks kind of like, oof, not great. But by a year and a half, he was able to get overhead function with it and you can see excellent external rotation there. So again, you have to be patient with some of these. Now about a scenario where you have a weak deltoid but you have a good rotator cuff. This is a good opportunity to do a pedicle pectoralis or a pedicle latissimus transfer. This was a young man who had a chondroblastoma, resected, reverse total shoulder arthroplasty but had a chronic axillary nerve palsy. This is a paper from Mayo, El Hassan, showing very nicely the separate blood supply and nerve innervations to the three heads of the pec. So you can separate those three heads, the upper and lower sternal half and the clavicular heads and then transfer the superior two-thirds of the pec. So we're showing intraoperative stimulation going to the clavicular head and the upper half of sternal there and then the lower branch that does the sternal head that we've left intact. And then we can, once we've completely mobilized that, we can open, turn the page as I call it, where you flip the upper two-thirds of the pec over and secure it to the clavicle and anterior acromion and then secure it to its insertion distally to give anterior deltoid function. And then we cast him for six weeks. And this is another study from Mayo showing improvement in shoulder flexion significant as well as some external rotation improvement as well. And this young man is from Tennessee, but we did a telehealth visit during COVID and he actually did great with that by six months post-op. So when you don't have good deltoid recovery, you don't have good suprascapular nerve recovery, but they have shoulder control, you can talk to them about maybe doing a pedicled pec and or lower trapezius transfer. They may be content with just living with it, but it can give them ability to reach forward and shake hands or open a door, so it may be worth it for them. And then finally, if they really have no recovery and it's a filial shoulder, they can either live with it or consider a shoulder fusion. So in summary, you want to maximize your chances for success with your initial transfers using all the techniques and principles that we've discussed thus far. We want to identify and address all elements of the shoulder injury initially. And when the transfers don't work, consider what you have and what you need to improve your clinical function. Thank you. Brian, that was fantastic. Thank you. Covered everything that we wanted. Questions for you. So there's a camp of thoughts saying maybe let's leave the spinal accessory alone and the trap alone to save it as a spare part for the future. You seem to be along the lines of wanting to use a spinal accessory to reinnervate the rotator cuff if your suprascapular nerve is out. Have you been satisfied with your ability to restore external rotation with that transfer? Yeah, great question. So I actually don't do it very often in adults. In babies, we'll routinely use a spinal accessory to suprascapular, but the results for whatever reason, even with that post-year approach, haven't worked great. And lower trapezius transfer, ipsilateral especially, has been very reliable. So actually, we often will not perform the spinal accessory to suprascapular transfer. And then last question for you. How strong of a deltoid do you need to power a reverse, and how do you assess that? That's a great question, and there's not really an answer for it. I arbitrarily have kind of used about 50% recruitment on an EMG, where I can clearly palpate the deltoid as functioning, but they just can't raise the arm. And I tell them, I've done like three of them, and there's only one patient in the literature on it, that it may not work. And I give it, like I said, 18 months or so to see what's the max they're going to get. But it's a little bit of a guess, and they have to be able to take on the potential outcome of it now. Got it. Thank you. All right, Jaime. So Dr. Bertelli is going to come up here. Jaime is visiting us from Florianopolis. Thank you for joining us. Good afternoon. My speech now is about nerve transfer for radial nerve palsy, and I will begin with what I think we should do, and how I can rescue a failed nerve transfer. My speech is about nerve transfer on radial nerve paralysis, but radial nerve paralysis does not mean only radial nerve lesions. You can have signs or symptoms of radial nerve paralysis in tetraplegia, in brachial plexus lower type injury that are similar, both of these concerning the treatment. We can have brachial plexus injury, what I call the T1 hand, lesion from C5 through C8. This is the most common lesion of brachial plexus considering upper type paralysis. And you have just the T1 hand function. In those cases, you need, in half of those patients, to reconstruct also the radial nerve. And then we have the real lesions to the radial nerve and the posterior cord. We're going to begin with elbow extension in different scenarios. This is elbow extension in tetraplegia. So what I do, I take the entire posterior division of the axillary nerve. This is an axillary approach. I don't do anymore the posterior approach. With this approach, I can connect both of my nerves without dissecting, and I have everything in front of me. I just call this the wind of the axilla. And I have connected the triceps branch to the posterior division of the axillary nerve. Here, just for remember, we are treating a tetraplegic patient. My goal is to restore elbow extension. Then we come to another point, posterior cord lesion. In that situation, my axillary nerve is not functioning. I have to think something different. And in that situation, I propose the transfer of the nerve to brachialis to triceps branches. And then you can expect a very good result, very difficult to have failure on this case. They take a little longer for understanding how it works, but by then they can understand and it's useful surgery. Then we come a little bit on proximal radial nerve injury, a little bit different lesion. And I put here my preference, that is to transfer the toracodorsal nerve to the triceps motor branch. Why is not in this situation I'm talking about the brachialis nerve transfer? Because it's not rare that you have this infraclavicular lesion affecting the radial nerve together with the musculocutaneous nerve. So now you have to have another possibility to reconstruct elbow extension. And just one point that means elbow extension is much better reconstructed by nerve transfer than by muscle transfer. This is an important point if you think about reconstructing the elbow extension first on nerve transfer. But then sometimes you have failed. And what to do? Including in tetraplegic patients. We published this paper recently in the journal Hand Surgery. It was concerning mostly about tetraplegic patients that fail to recover the strength I would like them to recover. So one possibility. Don't be desperate because if you have operated those cases and you have nothing to offer, you have the lower trapezius can be transferred as an elbow extensor. So this is my tip if you have done enough transfer and it's not working. You take with the fascia between T12 and L3 and then it can reach the tricep stem. We talked about elbow extension. Then we are going to move to the wrist, thumb, and finger extension. Just to remind you that we are talking about radial nerve. We come back with tetraplegia. And in tetraplegia we mostly need to reconstruct in the ideal case thumb and finger extension. There is a nuance here. If your patient just needs thumb and finger extension, better to go through a posterior arm approach. If you need to reconstruct finger flexion, then the anterior elbow approach is the first image, it's okay, because then you can transfer the ECRB motor branch to the AIN. To notice, with a single incision, you can reconstruct thumb and finger extension together with thumb and finger flexion. Then, sometimes we have fear with this nerve transfer, and how can you upgrade your results? One thing that we can do is tighten or shorten the finger stencils and the thumb stencils, just removing and this will improve the tinnitus effect. Another option is to transfer half of the FCR, and then maybe you are imagining, why Dr. Bertel is not transferring the FCU? It's easier, because it's paralyzed. I'm talking here about the trapezius patient, or any kind of patient that have extended lesion, and the only wrist flexion present is the FCR. If you go and you do an arthrodesis, and then you have your FCR free for transfer, you lose the capacity of getting the tinnitus effect. And when I say doing just MEFCR, it's not one tendon, two functions. You leave half of it in place, and you transfer just part of it. This is a dramatic case, and then just to not, to have some hope to the patients, you still can do something else. We then arrive to the T1 hand. The T1 hand, four root lesion. Half of those patients, they have, together with signs of upper type lesion, radial nerve paralysis. And it's very important in those patients to reconstruct wrist extension. Otherwise, when the patient is gonna bend the elbow because of your oblane nerve transfer, this would be hemiplegic effect, I call oblane effect, because elbow flexor, FCU, comes here, and then the patient, because of no wrist extensor, flex the wrist. My preferred technique for nerve transfer is the transfer of the AIN to the CAB motor branch. It's a very good technique that can give you very good results. In my series, 90% of M4. Indian series, 100%. Okay, at least we can have some hope that we're gonna reconstruct those elbow extension in those patients. But if that fail, then you have to do something. And my preference here goes to the transfer of the FDS of the third and fourth finger through the interosseous membrane, and then I attach them on the third metacarpal. Then we almost at the end of my presentation, because now we are gonna talk about radial nerve injury, and the case, in some case that they can have fail, what we can do for them, for those patients. So I treat the radial nerve paralysis by triple nerve transfer. And the triple nerve transfer consists in transferring the SCR to the PIN, the distal pronator teres to the CAB, and then there is a third guy here, that is the distal AIN to the DP. And when I talk about the DP, I'm talking about thumb, because if you do just FCR to the PIN, the thumb will not recover as expected. The thumb needs a nerve transfer just for itself. So this is an image from where I transfer the distal pronator to the CAB, and the FCR to the PIN. And some backup surgery is that the pronator teres to the CAB, and the FDS to the third metacarpal. This is for wrist extension. And in that case, when we are talking about the radial nerve, I took, I rather, just the one branch of the pronator teres, the other is there, and the most important I left, that is the proximal one, it's the one that is followed by the pedicle. So it still can be used. And then for finger and thumb extension, this is something that is important. If you have FCU and EDC, if you have FCU and the palmaris longus is there, then you can transfer the FCU entire to the EDC. You need to have always a wrist flexor in position. Otherwise, you cannot get the tenodesis effect. If you have palmaris longus paralyzed or absent for any reason, then the goal is to transfer just half of the FCU, and half of the FCU, the other half you left in place. Just, I have a short video. There is sound, I don't know how I can play it. I think we don't have sound. You don't have sound? We don't have sound. Oh, okay. So this is an anatomical dissection of the transfer of the distal AIN to the deep pin. When I talk the deep pin, it's the branch that I'm showing you here, it's the deep portion of the posterior interosseous nerve that goes to the deep layers of the muscle in the posterior forearm that's responsible for thumb innervation. So we are working in nerve transfer just for the thumb. We have already done FCR and NCAB reconstruction, and now I'm showing you that the deep pin has two divisions, one that goes to the extensor index propius, and the other that goes to the thumb. But we are focused on the main trunk that is the deep pin. And here between the extensor policeus longus and brevis, I show you the interosseous membrane, and over the interosseous membrane, the distal posterior interosseous nerve that is sensor in function. That's not important. It's just to locate on what is an anatomy of the division of the posterior interosseous nerve. This is where I place the incision, and then I see where the extensor capillary radialis became flat, and over the tendons in the posterior forearm, I draw my incision. This is here I'm already dissecting, opening the skin, and we are gonna get to the interosseous membrane, and first to the posterior interosseous nerve between the extensor capillary radialis and the extensor digitorum communis. And now here is the posterior interosseous nerve, and we see the two divisions, the lateral one and the medial one. We don't need to know this for reconstructing it. It's just the lateral division is three centimeters from the end point of the abductor policeus longus, so very short distance for re-innovation. And now I'm moving distally because I need to reverse my donor nerve. This is the interosseous membrane. You can take your nerve simulator, nerve locator, and it simulates to the interosseous membrane. You're gonna find the anterior interosseous nerve. Then here I have just divided the anterior, the interosseous membrane to find the distal AIN. This is the nerve. This is the branch that is going just to the prenatal quadratus. We are gonna work a little bit on it distally and proximal in order to have a coaptation free of tension. It's finishing. And just I'm cutting the PIN, flipping it distally, and I will cut the distal AIN, the branch that go to the prenatal quadratus, and flip it proximally, and then under the microscope, I coaptate both nerves. So for those that might be interested in our peripheral nerve course in Cali, Columbia in November, you can get places to you and may develop more skills on the nerve transfer. Thank you. That was wonderful. I have a lot of questions, but I know that we've got one more speaker, and Holly's gonna take us home here. Dr. Holly Power, coming from the University of Alberta. All right, thank you. All right, thanks, Chris, for the invitation. It's an honour to be included among this illustrious panel of nerve nerds, in your own words, Chris. So I'm gonna talk about ulnar nerve transfers for intrinsic function. So just going back to the basics, some other speakers have touched on it as well, but how do we ensure optimal outcomes after we do a nerve transfer? So I think of three things. The first is that you wanna operate on the right patient at the right time. You wanna perform a technically sound operation, and you wanna have appropriate post-operative rehab. We all know that repair after a high ulnar nerve injury, for example, doesn't tend to yield reliable functional outcomes. And if you look at the anatomy of the ulnar nerve in the hand, it's more complicated relative to the other nerves that we've heard about this evening. One of the benefits of nerve transfers is that you can theoretically reinnervate all of these muscles as opposed to tendon transfers, which is one tendon, one function. However, my co-panelist, Dr. Bertelli, has recently shown that maybe not all of these muscles are equally as important in terms of functional priorities. In terms of patient selection, so this is a really general slide that could really apply to any of the nerve injuries that we've talked about this evening, but for timing of your nerve transfer, for complete proximal injuries for ulnar nerve, I'm gonna almost always perform a nerve transfer acutely. Incomplete injuries, Dr. Shin mentioned this, no clinically meaningful recovery. You wanna get on repairing those within three to six months, four to six months is what I wrote. The electrodiagnostic testing is extremely important in your patient selection, and I point you guys to this wonderful review written by my co-panelists, Dr. Di and Dr. Brogan. Essentially, you wanna make sure that those recipient muscles remain receptive to innervation, so there should be fibrillations and positive sharp waves, and you wanna have a normal donor nerve as much as possible. Patient factors, other speakers have touched on, so I won't go into that. And there's two main transfers for ulnar intrinsic function. The first is the AIN to ulnar motor nerve transfer, which we're all familiar with, that transfers the pronator quadratus to the deep motor component of the ulnar nerve, popularized by one of my mentors, Dr. Susan McKinnon. End-to-end transfer, usually you're gonna perform that for proximal ulnar nerve injuries where you have no anticipated recovery. Reverse or supercharge end-to-side is generally performed when you anticipate some recovery from proximally. Now, just a few words on the technical aspects of this operation, because I think the devil is really in the details with any type of nerve surgery. So this would be my typical incision for an end-to-end transfer. I'm always gonna release Ghion's canal because I wanna remove any distal site of compression and have a clear pathway for a recovery of that deep motor branch. Once you're in the forearm, that coaptation is going to be about, can you guys see that? Yeah, nine to 10 centimeters proximal to the wrist. I usually would elevate the FTP off the ulnar for a couple of centimeters. You divide your pronator quadratus, harvest that AIN where it neurotizes the muscle. You often have to divide some crossing vascular branches overlying this AIN to ensure attention-free coaptation with no kink. And then you wanna dissect your recipient proximally in order to have, again, attention-free coaptation. The nice thing about this transfer is that the anatomy is really consistent. So that motor fascicle is routinely located right between the two sensory components. You can trace it back from the hook of the hamate using a visual neuralysis technique, or you can directly neuralyze this if you prefer. Neuralyze it. If you're doing a supercharged end-to-side transfer, you really need to work for every single millimeter of that AIN. So you wanna take all of those little branches because you're not having your recipient swing over to meet your donor. If you're with the end-to-side transfer, again, you wanna have a large epineurial-perineurial window to allow axon and Schwann cell ingrowth into that deep motor component. And again, tension-free is the name of the game here. What does the literature say in terms of outcomes for this transfer? So Salam and colleagues looked at 52 patients. Group one had nerve graft only. Group two had the nerve transfer. 57% of patients with nerve grafting achieved antigravity strength, whereas 83% of the nerve transfer patients did. Not bad. Looking at the end-to-side transfer, Coriam and colleagues, 21 patients with acute high ulnar nerve lacerations. One group had repair plus the nerve transfer. The other group had repair alone. And if you look at 18-month outcomes, excellent results in only 40% of the repair patients versus 91% with repair and nerve transfer. So clearly, there's good evidence in the literature to suggest that this nerve transfer works, but it's not perfect. And a criticism of this transfer is that perhaps, you know, the distance is long to get to the FDI and the adductor. Perhaps the axon count isn't sufficient. And so that has led to this new nerve transfer, which all of us nerve nerds are pretty excited about, and this was described by Dr. Bertelli, and that's transferring the opponent's pollicis branch of the median nerve to the terminal deep motor branch. So that gets you a lot closer to re-innervate the adductor pollicis and the first dorsal neurosius. So this is a interoperative photo of a recent case that I did. I think this nerve transfer is a lot more technically demanding than the AIN transfer. You're really deep in the palm here. It's actually hard to even get a great photo. You start by getting your donor, which is your opponent's pollicis branch, second off of the recurrent motor. You then have to get the index finger flexor tendon out of the way. You get the radial digital nerve to the index finger with its lumbrical branch out of the way. Divide the raffia between the two heads of the adductor, and you'll find your terminal deep motor branch there. This is just an interoperative video of the same case. This is a high ulnar nerve laceration treated within 72 hours of injury. So you can see stimulating the donor there. And then what's nice is you can also stimulate the recipient as well. But again, you see you're working in a bit of a hole. So again, this is a newer transfer. We don't have a lot of literature. There's this small case series of three patients by Dr. Bertelli with really great outcomes. So 15-month follow-up, all had re-innervation of the FTI and adductor. Pinch-to-zoom strength improved 80%. That's much better than we could ever get with a tendon transfer. And most importantly, thumb opposition was not impaired. So I'm pretty excited about the prospect of this transfer as a potential salvage option or even primary option for high ulnar nerve injuries. I put together this algorithm, and I think I was reviewing my talk in preparation for this presentation. And I was thinking, oh, I must have had some rose-colored glasses on when I made this because this kind of assumes that the patient is being referred to you in a timely fashion, which obviously is not always the case. So if your patient is like five years out from their injury, this algorithm maybe doesn't apply. So you've done your perfect surgery on the perfect patient, and you have inadequate recovery. So first I would start with getting an EMG of the recipient muscles. If there are motor units present, great. You're probably gonna see further recovery. And I think I would observe that patient, and then I'm gonna make sure that they're doing appropriate therapy. I think for this nerve transfer or anything involving the ulnar intrinsics, the therapy is really important postoperatively. In my practice, that's donor activation-focused rehab. And my mentor, Dr. Amy Moore and Lorna Kahn wrote this great review article that you can all look up if you'd like that details how these protocols work. Essentially, as surgeons, we get the nerve to the muscle, but our therapists are the ones who are responsible for teaching the patient how to activate it. With the intrinsics, they're biomechanically more complex than, say, a biceps muscle. So sometimes, especially in the early phases of recovery, it's not always intuitive, the types of strengthening activities that the patient needs to do in order to activate this transfer. An extension of that is using surface EMG biofeedback. So this works on the premise that you can get electrical activity prior to any clinically evident muscle contraction. So you can put surface EMG electrode over the pronator teres as a surrogate and over the FDI, the patient can activate it, the donor and the recipient, they can get a visual feedback on this machine, and then that sort of jumpstarts that cortical relearning process. If you are in the camp of the EMG shows that there are no motor units and you're still within a reasonable timeframe, so nine to 12 months max, I would look for spontaneous activity. If there is some present and they just had, for example, an AIN transfer, you might be able to consider doing this more distal opponents transfer as a salvage. I think practically speaking, the patient's probably, you're not gonna get to them in time to do that, and most patients are gonna need a tendon transfer for salvage. Tendon transfers are a whole talk in and of themselves, but just briefly, my primary functional priority would be to restore pinch. I really like ECRB as a donor for that. It's strong, it's synergistic. One of the downsides is that the tendon is not long enough, so you need to lengthen it, either with a tendon graft or by splitting it and sewing it to itself. Clawing is symptomatic in some patients, but definitely not always mandatory to be corrected. Donors for that, ECRB, FDS, both work great. The downside of FDS is that you are gonna get some weakening of your grip strength, which is not ideal in an already compromised hand. So ensuring that we're successful with nerve transfers. See, I kind of flipped your title of your course around there, Chris. Very positive. You wanna make sure you operate on the right patient at the right time. You wanna perform good surgery, do the right post-operative rehab, and if, unfortunately, it doesn't work, you might be able to consider a distal nerve transfer, but more likely, the patient's probably gonna need salvage with a tendon transfer. Thank you.

nerve transfer

elbow flexion

careful decision making

surgical technique

alternative treatment options

failed nerve transfers

ulnar nerve transfers

patient selection

tendon transfers

rehabilitation

successful outcomes