And finally, we'll close the tumor section, limb amputations and prosthetics. All right, I'll briefly talk about replantation and transplantation, and then focus on what are amputation goals, what are the levels, and then the prosthetics themselves that we might use. So for replantation and transplantation, Cody Azari gave a great talk on this Friday afternoon. The more proximal the amputation, the more muscle it is, the less tolerant of warm or cold. The schemia time and the longer the nerve axons have to travel to get down to their target. For transplantation, the good news is we've got all the donor tissue that we want, and we can cold preserve it essentially immediately. But there's the immunology and the ethics of immunosuppression. I won't get into that today, and it's not going to be on the test. The goals of amputation surgery, we want to keep as much functional length as we can. Durable skin envelope, we would like to be sensate to help prevent with breakdown issues, and we would like to operate on our nerves in a manner that will minimize the risk of painful neuromas. We want the adjacent tissues to be mobile. We want it to heal quickly so we can start rehabbing them quickly, which will allow them to get back to whatever activities they can as quickly as possible. Also, get the prosthetist involved early. Most communities have a prosthetist somewhere in the neighborhood, and at least all the ones I've ever called, if you say, hey, I'm going to be doing an amputation on somebody in three days, is there any way you can come see him in the hospital? At least in my community in Baltimore, they've been great about coming in. It lets the patient have a much better expectation about what's coming and what the rehab might be able to be once they're done. So multiple levels of amputation, from the finger level to all the way up at the shoulder. I'll focus mostly on the upper arm and distal. So this is a question from the self-assessment exam last year. I'm not sure how well you can see the photos, but basically the question is, which one of these does it not make sense to replant? And if you can see it well enough, the middle photo is a single zone to index finger injury. Regardless of the activity level of person, it's not going to be a very good result. All the rest of these are hand, multiple digits, thumb, all things that we would agree we would replant. After index finger rate resection, the percentage of group strength compared to the normal will be expected to be in the range of. And this is actually more of a decrease than you might expect, and this is because the span of the hand gets narrower. So moving on to the types of amputation. So you can do a transmetacarpal amputation, just like our orthopedic and vascular colleagues can do transmetatarsal amputation. The good news is it keeps the full wrist, so you can flex, extend, rotate. Variable reports on sensibility. And if you are able to keep some thumb, you may have some ability to pinch against the prosthetic that you would put over the fingers. But generally speaking, this is a static prosthesis. It's cosmetic, but it's not necessarily very functional. Wrist disarticulation might, in concept, appeal to you. You retain the distoradial ulnar joint for rotation. It is a little bit harder for prosthetic mounting, in the sense of you have to get around the radial styloid and the ulnar styloid. These are fairly big. And since you have the full length of this, it's hard to put in a mobile wrist component that will flex and extend. So this is generally a less favored level. Which amputation level is associated with the highest rate of prosthetic use? This shows up on the self-assessment every second or third year. So this is something that seems to be favored as a test question. And the answer is transradial or transform, if you prefer that term. Transradial is the anatomic term of it. Now, there are different levels of transradial amputation. And basically, the longer the form that you retain is, the better lever arm for elbow flexion, the better control and range of motion of rotation that you'll have. That being said, again, you need a durable soft tissue envelope. So if you need to go a little bit shorter to do that, that's still the right thing to do surgically. When doing a forearm amputation, why do we want to sew the muscles over the end of the bony stumps? We're going to minimize bursitis. If you have raw bone and skin and fat over it, you risk forming a bursa over the end of it, which will make your prosthetic unstable or increase the risk of wound breakdown. Kruppenberg procedure, out of curiosity, anybody in the room ever seen a living patient with one of these? Any of you in the US or internationally? In the US? OK. So very rarely done, but people tend to like to ask questions about it. Basically, you're going to separate the ulnar and radial rays and skin graft between them. The idea is the pronator teres will allow them to pinch. As you can see, this is very disfiguring to the patient. And the guidelines in literature are they should be blind, meaning they shouldn't be able to see it on themselves. May be appropriate for children. But most importantly, if you're in the third world and it's somewhere where they just can't get prosthetics, it may be the most functional that will be able to be durable for the patient over time. Never do this as a primary amputation. And there needs to be a lot of counseling about what this is going to look like before you do it. 40-year-old heavy laborer. Amputation 5cm proximal to the pronator teres insertion. Full flexion extension of these. Actually, I'm just going to skip through these in the interest of everybody's time. Rigid elbow hinge. So elbow disarticulation. Again, this is something that might be conceptually appealing the same way a wrist disarticulation is. The good news is having the epicondyle of the humerus can make a more rigid mounting of the prosthesis. The bad news is because you still have half the elbow joint, it's hard to make an elbow that flexes and extends. The other advantage is it makes for a big open incision. You can do all your nerve excisions through the same distal incision. But it's a little bit harder for a prosthetist to mount a good prosthesis over it. And so it's generally a less favored level of amputation. Once you get to the transhumeral level, something to be aware of, the Marquardt angulation osteotomy. The advantage of that is by creating a bend in the humerus, it's easier for the prosthesis to mount. And you may not have to have a harness that crosses the midline. As compared to your standard transhumeral prosthesis, there's actually an upper body saddle that has to cross the midline to keep it in place. So again, for a transhumeral amputation, we want maximum length. If you're not going to do the Marquardt osteotomy, you will have to use a harness to adjust to the other side of the body. While you can have a mobile elbow and wrist, this is generally fairly time inefficient. The patient has to first adjust the elbow position, lock it, then adjust the wrist position. And while patients can get somewhat proficient at it, it's slow and it's a little bit awkward looking. This is an area where targeted muscle re-innervation that I'll talk about in a moment can be potentially very helpful to patients. Osteointegrated prostheses are described for the upper extremity, very efficient for prosthesis mounting. Obviously, all of the things about infection control that you would worry about. So you need very good patient selection if you're going to choose them for this. More proximal amputations, just to mention them. Once you go above the pectoralis major insertion, you're going to have very little control of the shoulder. And then true shoulder disarticulation, forequarter amputation, most of these are going to be oncologic directed if you have something that is right up at the shoulder level and you just, you can't get tumor clearance without taking too much of it off. There have not been any questions about this on the last nine years of self-assessment exams, so I think that's less likely. Stump issues, these are the things that we can help with. Phantom limb sensation and pain. Almost all patients will have at least phantom limb sensation. We're going to try to keep it less painful for them. Epidural anesthesia in surgery has been shown to increase the risk of this. Aggressive pain management after surgery has been shown to help with this. Have a pain management colleague on board if you're less comfortable with the higher doses that they might need. Painful neuromas, there's some literature to show that if you sew the nerve stumps to each other, that may give them enough of a target for their nerve sprouts that you will get less painful neuromas. And then, fairly obvious, but don't put your nerve stumps anywhere near bony prominences or your skin edge. Anywhere they're either going to be close to the skin level or get pressure from the prosthesis, those increase your risk of pain. More prosthetic amputation. So this is one I'm actually just going to go through. How soon should you start them with a prosthesis? Whatever the question asks, the shortest interval is the right answer. For those who are healing well enough to do it in the first week, do it in the first week. And one study even advocated within 24 hours of surgery. And the reason is there's very strong literature both in the upper and lower extremity that the sooner you get them rehabbing to a prosthesis, the sooner their pain gets better and the more likely they are to use their prosthesis durably over time. So all those things. Again, transradial is the highest in terms of all comers of upper extremity amputations. The highest percentage of people who will use their prosthesis in the long term. Lots of different terminal devices that have very different appearances and very different functionalities. Remember right now, our prosthetics are fairly insensate. That may be different in 10 or 20 or 30 years. But so the advantage of a hook is the patient can see through it, see what it's grasping better. Hands look better, but are generally not as mobile and the patient can't see through the part that is closer to them. Lots of different end terminal devices depending on what the patient's needs are for specialty occupation needs, specialty ADL needs. Really the prosthesis can do all kinds of amazing things. Again, if you have a patient you think might need this, it's great to have a conversation with them before your amputation happens. Joints and sockets. Again, you can have for your transhumeral amputations, you can have an elbow and a wrist, but it gets bigger, it gets heavier. And depending on who the patient's payer is, it gets more expensive. For sockets, these are generally much better than they were 10 and 20 years ago. Computer aided design has shown some benefit for this. And then just general suction technology has helped to keep the prosthesis in place better, less risk of wound breakdown and bursitis, and a more stable prosthesis mount that allows it to be more functional for the patients. Again, early initiation, as soon as the wound is stable enough to tolerate it, get them at least a training prosthesis. They'll hurt less, they will be more likely to use their prosthetic. Lots of very smart engineers are working on HAPICS, working on the ability for the prosthesis to transmit a sensation signal that the patient can actually identify without seeing, I'm touching something now, we're not there yet, but there's a lot of good engineering being done. Remember, for any individual patient, they may have different needs depending on time of day and when they're at work and when they're not. So they may need both body powered and electric powered prosthetics. So this is a question that comes up fairly frequently. What is the good news about body powered prosthetics? And there are a couple of things. There's lower maintenance, they're less expensive, and they're simpler. They're a little bit easier to teach the patient to use. So depending on where in the world you are, depending on what your patient's resources are, body powered prosthesis may get used better, but they're much simpler in their concept. They're also lighter and they may be more durable, which is more to say that the myoelectric prostheses have components in them that are a little bit fragile, some of them. However, there may be a psychological perception that they're getting out of date prosthetics, that this isn't the best that modern technology can do. Myoelectric prostheses can do some pretty amazing things these days. Where I'm in Baltimore, we have a lot of interaction with the Hopkins Applied Physics Lab and they have one patient with a prosthesis, he can throw and catch a ball one handed. It's really impressive to see. His prosthesis, however, costs a quarter of a million dollars and has a battery that lasts four hours. Now that's getting better, it's getting less expensive, and it's getting more durable. They're also heavier. So those are all the things where the engineering is gonna need to get better, but it is continuing to get better. So again, your differences between your body powered and your myoelectric, body powered, lighter, cheaper, a little bit easier to use and more durable. Myoelectric can sit in something that looks like a hand, can be very precise. They're getting stronger, they're getting faster, they're getting lighter, but they're not there yet. And they're getting cheaper, but they're not there yet. Other questions that may come up for a 10 year old child. Basically, any child old enough to have a conversation with you should have a conversation with you, with their parents, with the prosthetist, about what they think they will use best. Not a uniform agreement on what terminal device should be. Again, if they're old enough to have a conversation, at least have them involved in the conversation. All right, moving on to targeted muscle reinnervation. The idea is we have these amputated nerves that are going somewhere that doesn't exist on the body anymore. Can we subdivide the muscles near the end of the amputation level to provide signals for the receptors and the prosthesis to take up to? So for example, a transhumeral amputation, you've got a median nerve, a radial nerve, and an ulnar nerve, can we use the long versus the short head of the biceps? The three heads of the triceps, multiple heads of the pec major, to then get better differential motion of finger versus wrist versus elbow of our prosthesis? And the short answer is yes, but you need to be somewhere where the prosthetists are used to doing that. And this is very much a work in progress, but very exciting in terms of what can get done. The more places you need an EMG sensor, the heavier your device gets, the shorter your battery lasts, and the more expensive it gets. So all of these are things that are getting better, and in some places can do some very cool things, but are not uniformly available for everyone yet. So in summary, if you can do it on the front end, talk to your prosthetist before you do your amputation, figure out what their abilities are in order to give the patient the best rehab. Again, if it can be planned, let the patient see the prosthetist. They'll show them some photos of various prosthetics that can be used. It gets them more prepared for what's coming. Rehab as early as the stump will allow you to do. Control pain, involve your pain management colleagues early. Haptics, the ability of the prosthetic to have sensation is getting better, but we're not there yet. And in terms of precision and multi-joint motion, targeted muscle re-innervation allows us to do that better. We're getting better at it, but it is still more expensive and makes for a heavier prosthetic.

limb amputations

prosthetics

replantation

transplantation

amputation goals