So what we're going to do now is demonstrate what I think is probably the best of the nerve transfers which is the double fascicular nerve transfer for elbow flexion or what's known as the Oberlin transfer named after Christoph Oberlin of Paris. And this is a good operation which is pretty straightforward and works most importantly perhaps. So we've already got this, normally I would make a medial incision here in the medial arm and it has to be fairly long because the distal part of this transfer is a little lower than you'd think and the anatomy can be fairly variable as we've sort of seen from our proximal intersection. So we're going to come in here onto the... That's your medial cutaneous nerve of arm I think here that we were looking for above. Go through the deep fascia, so that's the arm branch, take that posteriorly. And the first thing we want to get down onto, this is a little posterior, that's triceps I think, there are these triceps. I might just, for the sake of ease, I might just do this. Thanks. So we're coming down through the medial arm, down through the subcutaneous tissue. Now we're coming, that's on, that first thing that looks significant is going to be the medial cutaneous nerve of forearm. The medial cutaneous nerve of arm as I said before is this little thing here. So the easiest thing to start with is to come down onto the fascia of biceps and open that up rather than getting stuck into the neurovascular bundle primarily. So if you come onto biceps, open that up and that allows you to retract biceps up which will give you a look at the, that's satisfying. That will help you find the nerve to biceps earlier, musculocutaneous and nerve to biceps which I think is going to be this one. This is a bit of a crime but to make the exposure a little easier I'm just going to do this. So, medial cutaneous nerve of forearm, this is the first one you come across. And then biceps above, so next step is onto biceps fascia and then we're onto, we're looking at this vascular hilum up here in the upper third of the arm and that's going to tell us where our biceps branch is and this I think is coracobrachialis which is, we've taken with us here, actually no that's not coracobrachialis, this is coracobrachialis here. This is long headed, short headed biceps and it's got a dual nerve supply. There's this one and then there's going to be another one over here. So, this is kind of unusual, this means that this is, if you remember we had this musculocutaneous nerve, median nerve and then they're reunifying so we've got to combine musculocutaneous median nerve with nerve to biceps, a branch of that. So, that's a little unusual. But that's our branching here, we've got a little branch over here and a bigger branch there. So, they're the branches we want. We'll go down and find our brachialis branch now and that's distally and it's usually associated, it's usually in the distal third, it might be a little bit difficult here because of the, it's got some variation. So, in the normal setting we're looking for two lots of branches, one will be the lateral cutaneous nerve of forearm and then the other will be the nerve to brachialis. But here he's got this sort of combined median musculocutaneous nerve anatomy. So, here, this is what I was talking about before, there's this second, you've got this vascular leash here with the first set of branches to biceps and you come down further and you see another vascular leash heading to the muscle and that's where the second, that's where the nerve to brachialis is. So, that's in here. Okay, and then this, the third branch of this structure will be LABC and if you look down at his cubital fossa, you can see that there. And Oberlin used to actually make a big deal of this and he'd in fact sometimes put a nick in here and find the nerve so that he could pull on it and make sure he's got the right thing. But I think if you can see the nerve going to the muscle, that's probably good enough evidence but that's not to cast aspersions on Dr. Oberlin. I think he knows a bit more about this than I do. So, that's lateral cutaneous nerve of forearm and it makes a lot of sense to, makes some sense at least, I think probably a lot more than some. Within limits, to do an interfascicular dissection, so you make sure you get enough length, the disaster or the crime with this operation is to leave yourself short. So, you have to put an interposition nerve graft in between your donor and recipient because that's going to ruin your result and sort of ablate some of the benefit of your operation. So, provided you're not doing a whole lot of harm, it's easy to do an interfascicular dissection on the donor nerve, the one that's not working, rather than run the risk of doing an extensive interfascicular dissection on the recipient, sorry, the other way around. It's easy to do the interfascicular dissection of the recipient nerve which isn't working than do the dissection on the donor nerve which potentially increases your risk of donor morbidity. Now, there's probably a limit to how, but equally you don't want to go up here so far that what you've got there doesn't equal what's down here. You've got to be a little bit cautious about that, but I think that's fine. And this is our bicep nerve here. If I'm going to do my coaptation and I've got extra length, I'm going to cut back on this side because the closer the coaptation is to the muscle, the shorter the regeneration time. So, there's my two nerves. And in terms of which one's which, in terms of donor, is there an issue with putting median to ulnar and, sorry, yeah, putting brachialis, there is an issue putting median to ulnar because that's not going to help. There is less of an issue deciding whether you go biceps to ulnar, brachialis to median. I think probably the median fascicle is perhaps not as good as the ulnar fascicle because if you think about myotomal distribution, the myotomal distribution of your FCU fascicle is going to be one myotome further down and further away from your upper trunk injury than your C7 FCR fascicle. So, you know, if you've got a C567 lesion, then you probably want to put your best fascicle, which would be your FCU fascicle, to what you perceive to be your most important muscle. Now, is that biceps or is that brachialis? I'm not sure. I suspect biceps is probably more important. This guy's a little unusual. We could do our coaptation. This is going to be his median nerve here and so this looks like a good spot. I'd put the elbow through a full range and make sure that you're not sewing something on that as soon as they either flex or extend their elbow, you know, pull the whole thing apart. You want to leave a little bit of laxity in that. Let's say we do it with my nerve stimulator here. So, Scott Cozen was at the meeting in San Francisco and he was doing the mantra of donor distal recipient proximal thing. So let's just say we've got a stimulator and we've decided that this fascicle here is our one. And I would be more careful than this in the real world. Perhaps I'd do something other than a pair of Adsens. Loops or a microscope? Look, I use loops for just about everything but I, if I was, I'd be tempted to get a microscope out for this because I'm terrified of the donor deficit here. And you see the pictures, you see Susan's pictures and she has a sort of, this thing opened up like a packet of spaghetti. And I, you know, you wouldn't do that to any other nerve in the body for any other reason because of the risk of, you know, pain and scarring. So I'm a bit reluctant to be really aggressive. But I think you've got to be, so what I think is a good idea is you can get some background and you can isolate fascicles and then, you know, test them individually and work out which one is FCR. I don't think you want to take the only fascicle that's doing finger flexion or the only fascicle that's doing intrinsics. But if you've got a fascicle that's a bit of this and a bit of this, but you've got another fascicle that's doing finger flexion, then I think that's okay. So it's FCR or redundancy, I think. And it doesn't seem to do a lot of harm. So then you just, you go, we're going to, we've done our nerve stimulation. We've decided that this is a pretty good size match and it's got the, it's got the, and we're going to do our thing about here. So I'll do it up here just because I've dissected it there. So we're just going to go pop. Maybe. Take, oh, I better take one. You wouldn't cut two and just take one. Yeah, that'd be a bad policy. That'd be a bad policy. We won't do that. I feel really bad about that. Just put it back. Yeah, just, there we are. It's just, it's okay. And there we are. I'll tell you, I've only done a couple of these, but both times I said to myself at the end of it, these things are so small. You want to run outside. You do. You feel terrible after you cut it, but you do sort of say, wow, that's it? Yeah. That's the upper end. But it's amazing how potent they are. Yeah, it is. So, so that's that one. That's done. And then we come back here and find our ulna, which is going to be just behind the vein. Just in here. You're in the Dominican Republic and you don't have a nerve stimulator. Is it, is it reasonable to choose a donor axon based on just your understanding of the topography, or is it just really rolling the dice? It's one of the big stuff here. Yeah. It's, look, I, did I, was I telling you last night that I was, went, went over to Paris and visited with Chris, Christopher, Christoph Oberlin, who, as I said last night, is a fantastic guy. Fantastic surgeon. He, look, there's a sort of a, there's a pretty proximal compression of his ulnar nerve. You don't need to be as low for the ulnar as, because it's, it's all the way up here if you're doing ulnar to biceps. He just picked a fascicle. When he did his, when he started doing the median nerve fascicle, he reckons he just picked one. And he did it on the basis of size. And look, he's, he does a lot of anatomy, so I'm sure he had a bit more idea than, he's a professor of anatomy, he's got access to labs and he did all his, his research on cadavers before he did ulnar fascicles. Before he did any, before he did any surgery on patients. But he just used to pick one based on size rather than using a nerve stimulator. I'm not sure why he didn't use a nerve stimulator. But anyway, he had some patients who had significant donor morbidity, particularly the median nerve. There we are, there's number two. Now with the ulnar nerve, there is a bit of excursion in the ulnar nerve, so you have to be, you know, when you do that, it pulls down. So there is a little, if you go into maximum flexion, you do get some longitudinal traction on your nerve. So you have to be a little bit cautious of that, I think. There you go. That'd be worth, though, definitely getting a nerve stimulator from the DR. Yeah, yeah. If you've got no alternative, because flexoplasty operations, in my experience, which is not enormous, but any time I've tried to achieve anything with like a bipolar LD or a bipolar PEC transfer or, I don't have a lot of experience with Steinlers, but it's such a, this is a heavy, this is, you know, it's a pretty heavy structure. And a flexoplasty, I think, is an unsatisfying procedure in general. Whereas this is, you know, those figures of 70 to 90% M4 function, I think are probably pretty true. Because you see, you know, if you look at how close you are to the muscle, you're really close. And, you know, you're putting big motor neurons in there. And I think that this gives you, allows you to stretch that out as far as you can. 14 months. Well, particularly, there's some, there's a guy from Israel I've seen present the same paper at about three conferences. It's a pretty small, insular world, the plexus thing. And he's done Oberlin's on teenagers with, with Erb's palsies, who've got poor spontaneous recovery. And he's come back and done an Oberlin transfer on them at 10, 12, 13, 14. So they've had partial but inadequate reanimation. So if you've got the closed injury where they've got something, then that's... Yeah, well this, for us, I mean... That's doable. If it's a kid, and they don't have a lot of other options, I think you give it a go. Especially if they, if they had a one on five muscle or a two on five muscle, I think there's, you know, you can do this. It's easier than doing a gracilis. We're definitely going to give it a go, you know, yeah. So 12 to 14 months with no reanimation. But if they've got incomplete reanimation, we don't know the answer, but it could be any time, apparently. It's got to be within 20 years, sounds like. Probably 20. I mean, I see these kids that have these birth palsies that, you know, it's like five years. Yeah, right. Nothing, you know, like what are you going to do for them, you know? I mean, it's not like it's a big hit, it's a scar on the inside part of their arm, you know what I mean? Well, Oberlin would reanimate anyone whose nerve studies showed that the muscle wasn't completely... Right. He still had electrical activity. He would do this. Now, he may have changed. I haven't seen him for a long time, five years or more, but that's what he was doing five years ago. And he's, as I said, he's a superstar. So I think it's, you know, it's not unreasonable. And the hit that they get, unless they've got, you know, if you've got a kid who's got a C567 and a bit of a weak hand, who's got some weakness in their hand, then I'm not sure that this is going to have... the donor morbidity will be greater and the result won't be as... I'm not sure about that. Yeah, so if they've got hand weakness, as in their grip isn't too good... You know, we're almost all the way there already. I put them on a... If I was doing the shoulder, I would put them in either a lateral or a prone position. Lateral's easier, the anesthetists don't kick up such a fuss. Now, I was somewhere recently where they were doing this operation through a short auxiliary incision, which I thought was pretty hard work and I'm only an amateur, so I make a sort of posterior deltoid incision. So I come down onto... And that helps because as we come through here... So the idea is to come around the posterior margin of the deltoid. Yeah, that's a good idea. And what we'll get to shortly is we're going to come down onto the cutaneous branch, upper lateral cutaneous branch of arm, which is going to give us a road home for the auxiliary nerve, somewhere in here. So I think that's it there. So I think that's it there. I think that's a nerve. Or is that just more fat? So we're coming down on the posterior border of deltoid. Not trying to get too lost. Maybe I'm lost. There we are. That's better. That's the cleft. So there's our deltoid there. Come down, develop that plane. It's a safe plane. So that's the vessel on the nerve there. That was just a little posterior. So that's the cutaneous nerve. So that's going to take us down to... Develop that. That's our auxiliary nerve going in there. Let's get a retractor in here. So there's our auxiliary nerve coming there. So that's an anterior and posterior branch. Here. So I'll just open that intermuscular space a bit more. Because the further you can go down on that... Yeah, this is a transfer where I think you do get a bit of... You can get into trouble with length. So you can... I think it is worth being able to get into the space. So you can see... He's got a pretty big nerve, this guy. He's got a slightly weird anatomy. He's got a bit of edema here. There. That's the auxiliary nerve. Okay. Yep. So posterior branch, anterior branch. Which one's more important? Susan McKinnon says you've got to innovate both. Some people say you just have to innovate the anterior branch. And the premise that you... Premise that your, you know, forward flexion, adduction is more important than shoulder extension. Sorry, I didn't mean to say that. But... The issue with this a bit is that this is a pretty big nerve and your donors aren't that big. So I think you have to be... Sometimes have to be a bit selective about what you're doing. So let's open this up. It'll make that exposure a little easier. So that's it. This is a pretty big incision, but we're doing that for the sake of everybody's... So... Now we're into this triceps. We're going to get into that sort of cleft that the triceps and these muscles all got a bit soft. You've got his lateral head out here. Mm-hm. And it's sort of just really in continuity with that plane that you've developed through here. So this is his long head of triceps there. There. This is long head. Okay, in between my fingers. And you've got this plane between the long head and then lateral and medial. Medial being deep. I might just put a deeper retractor in here. Just come out for a sec. Now... So that's all deltoid. I'm just going to take this branch down here because it's... So the triceps branches at this level are a bit, they're distinct from the radial nerve proper. So the radial nerve proper is down the base of this, that's in there. That's the radial nerve, that structure here. See there? Okay, but your triceps branches are going to be, like there's one, that's to the long head. This is going to be one to probably medial head. There's one over here. Hopefully that wasn't just here. But there's one to, I think there's a branch there to lateral head. And the lateral head branches are shorter than the long head ones. The long head ones often run further down. Now whether having a long head, which crosses, long head crosses the shoulder joint. So whether having a long head branch present, so you've got some, something. Because when you see people they'll, when they extend they'll reduce their glenohumeral joint. And so whether that's a thing that you ought to preserve or not. I don't know, it depends how confident you are in your other transfers. Are you going to get your rotator cuff back? I'm not sure. So again it's just really a matter, it's a little bit difficult on this guy because he's got a bit squishy. But it's a matter of working. What I would do is flick out my radial nerve, sorry, flick out my axillary nerve first. Usually kicking the anterior? Yeah, well, you know, if nothing else is going to re-innovate that. If you can afford to take out, you can afford to take, so you can afford to just do that without getting the vessel. So there's, so I flick my axillary down. There's some sensory fibers in here. That's why I would go to anterior preferentially. That would be my focus on that. Or else you could dissect out, you could take these out. Yeah, come down. Remove the sensory stuff? Yeah, do it in a vesicular dissection and take those down. So that they're not a factor. But I would preferentially go like anterior. I wonder is there, so walk through with me the logic. Some people would say you need to choose one. People would argue over which one's more important. Yeah. But if you take the sensory out and you put in even this wimpy nerve. Yeah. You might say to yourself, well, that's diluting my outcome, so I'm going to go with one branch. But do we really know that? You might say, I'm going to get more. Do you have, will you get, you know, one axon innovating five motor units and therefore being a better, some total being better? Yeah, logically makes sense, but. Just depends whether, you know, that one to five process really happens. Or do you just end up with a lesser density of active motor fibers within the muscle belly. And therefore less, you know, sure you get movement. But you're, I think you've got to be, the whole, potentially the whole benefit of nerve transfer surgery. Or, you know, directed nerve grafting is that you are targeting. Okay, I want to be able to, you know, this guy to be able to make a pinch. Rather than be able to use his pronator teres or be able to, because I can, I can produce pronation with one bone forearm. So I don't need that. But what I need is a pinch. So I think that, yeah, that's again, intuitive, non-scientific. Philosophical rather than.

double fascicular nerve transfer

elbow flexion

Oberlin transfer

nerve graft

fascicle transplant

Christoph Oberlin