• LecturehallPedal Amputations: The Details Matter
  • Lecture Transcript
  • TAPE STARTS – [00:00]

    Male Speaker: Next up, my good friend Dr. Jared Shapiro was going to talk to us about pedal amputations. For those of you who don't know Dr. Shapiro, he is board certified in podiatric foot and ankle surgeon, authored many articles and he is well-trained three-year foot and ankle surgery in Michigan, graduate of the California College of Podiatric Medicine in 2003 and is an editor of Present's Practice Perfect. So please give a warm welcome for Dr. Shapiro.


    Dr. Jared Shapiro: Thank you very much Dr. Bromley. So you guys are the hardcore folks who are here to learn. Good for you. So I will try to keep us on time and hopefully not relay. We are going to talk about amputations. I am going to focus on forefoot amputations in general, but we are going to talk about some topics surrounding amputations and hopefully they will help with some of the procedures that you are doing. So first of all, the decision making is the first thing that you really have to focus on. A potentially good amputation is going to be destroyed if you have the wrong workup. The patient has PAD. You haven't figured those things out. You have to figure out what level to amputate. Are there any adjunctive procedures that should be done and really what procedure is going to provide the patient the longest term stability? So of course, that's important. If you amputate and the patient survives all of five minutes afterwards, that's not going to be really helpful for you. So let's talk about some vascular details. For me the hardest patients are the ones with arterial disease. So let's talk about that. You guys have heard of angiosomes. In the vascular surgery world, there is somewhat with the shift towards targeting their vascular reconstructions towards angiosomes.


    This is a study that looked back on this and they saw that patients who had an angiosome targeted approach where they determine exactly which angiosome was the one that was the problem and then revascularize those and then compare them to patients with indirect revascularization. So essentially, revascularizing anything that you can open was much more successful than doing that indirect approach. So really looking at what angiosome is the one that's the problem is really where you wanted to target things. So of course, the question -- for many of these amputations, you don't have a choice. You are amputating for infection and you really can't wait and then you are going to deal with the aftermath afterwards. But when you can wait, a real question that comes up is really when should you amputate. Somebody with a chronic osteomyelitis that's you have a mild cellulitis, it's really well-controllable with antibiotic, it's really something that you don't have to necessarily rush in. But if they have peripheral arterial disease, the question really is when are your chances of being the more successful? So unfortunately, there is not a lot of research to really help us with this. There is only a couple of studies and both of these studies were looking at transcutaneous oxygen measurements in patients who then undergo amputations then measuring the TC, T-COMs over time afterwards. So this particular study looked at 23 diabetic patients. These were ischemic ulcer whether or not they healed after percutaneous angioplasties and they looked at them up to 28 days. And they saw that the oxygen content in the skin actually improved upwards of 3 to 4 weeks after the revascularization. So patients had maximum oxygen skin tension at 3 to 4 weeks.


    So that was a piece of evidence that's kind of helpful for us. The only other study that's done from the podiatric realm was really this one looked maybe half or so -- the patients 11. They looked at transcutaneous oxygen and those patients underwent open bypass. Then they looked at those T-COMs after the surgery and they found that at three days, those patients had highest TCPO2. Now unfortunately, they didn't look at anything past that three days and they really came just to the point, just slightly above the point where their T-COMs were enough to allow for wound healing. So they were recommending anywhere more than three days to amputate. So unfortunately that's all the evidence that we have as far as when you can amputate as far as those patients with vascular surgery. So really what we are tending to see here at least as far as this research goes is that oxygen tension tends to increase after the revascularization. Obviously, if you can wait until after the revascularization to do amputation, that would be better. We're seeing that it might be about three to four weeks that you're seeing the optimum amount of oxygen, which is really is going to correlate with your patient's chances to heal the surgery. And we have seen zero studies that are showing correlations between increased oxygen and the amputation outcomes. So lot more research needs to be done here. So my suggestion is if you can wait, try to wait at least a little bit. Remember that there is also the potential for reperfusion injury after the vascular surgeon takes care of things. So again more to come.


    So this is kind of example that kind of situation. This is the patient who presented to me, about 65-year-old who had no medical care for his entire life, comes in, is diagnosed with diabetes. Obviously, he has peripheral arterial disease. He has gangrene. You can't see it very well but on the medial side of his second toe, he is gangrenous as well. It all probes down the bone, but it wasn’t acutely infected. So I was able to wait, had my vascular surgeon do a fem-pop bypass and then the patient underwent a transmetatarsal amputation and Achilles tendon lengthening, came out with a pretty good result, fully walkable, was doing well at about three years afterwards when I was finished seeing him. The problem of course that we still have basically no treatment for is microvascular disease. So this is a similar patient, obviously severe PAD, noninfected, underwent a transmetatarsal amputation after having an endovascular revascularization. That looks okay, so we will go ahead with this. It looks pretty good. We are kind of happy. Here is postop day 2. You can see little corner starting to get a little dark and fussy. We are kind of now sort of keeping our fingers crossed on this one. There is postop day three. We popped some stitches. That's not pus coming out it. It's just some fibrotic tissue. And you could see that's really failing. This patient unfortunately because of his microvascular disease, went on to below-the-knee amputation. So what about our using angiosomes. So the work Ettinger has done is something that if you haven't read it recently is definitely worthwhile, really good work. What they have looked at is using angiosome is kind of help figure out your surgery. So one of the things that would be really good to know is depending on where your amputation is, is it going to survive if you happen to breach the artery, the perforating artery between the dorsalis pedis and the posterior tib.


    So if you look at this, you need to know whether or not the patient has antegrade flow or retrograde flow. So if they have antegrade flow on both directions, in that case, you are getting direct proximal or distal arterial flow in both vessels and if you were to amputate something and cut that perforating vessel in the first intermetatarsal space, the patient will be okay, those flaps are likely to survive. On the other case though, if you have an antegrade flow of the dorsalis pedis and then it's going to run through that perforating artery into the plantar arteries. If you then break that connection, then your plantar flap is at risk for death. And then of course on the opposite side of that, if it's mostly from the posterior tib up and then into the dorsalis pedis or dorsal foot, you are at risk if you were to cut that again but that now instead your dorsal flap is at risk and there is an interesting picture in Ettinger's article where you can see the failure of a transmet amputation that the dorsal flap ended up going into gangrene. Now the question is how do I figure this out? How do I know for sure if it's retrograde or antegrade flow? So I am going to show you one of these. So this is a patient where we -- you could see we are using just a handheld Doppler. Nothing special. You don't need any other equipment than this. So you have the Doppler on the dorsalis pedis. You compress the posterior tibial and then you're just listening to see if there is any flow left. In this particular patient, there was no -- maybe just a very slight, there was really no pulse left.


    You could not hear anything in the dorsalis pedis while pushing on the posterior tib and we know that there has to be retrograde flow from the posterior tib to the dorsalis pedis. Now you can try to confirm that by switching it. You have your Doppler on the dorsalis pedis and then you compress just proximal to it. If the flow was antegrade and coming from the dorsalis pedis then it should become quiet again. On the other hand, if there is some flow upwards from the posterior tib area, then you might actually still get a little bit of pulse left in that case and that's kind of what this patient has. So you switch it around then. You put it on the posterior tib and you are compressing the dorsalis pedis in this case and then you are going to look at this to see what's going on. In this particular patient, the pulse is maintained. So I know that there is then antegrade flow from the posterior tib into the rest of the foot. That kind of helps to be confirmed what's going on. And then finally, I want to see the medial and lateral plantar arteries if I were to block the flow to those, what would happen. So in this case, it's a little hard to see but I am on the lateral plantar artery. You can listen to it on the bottom of the foot. I can press the posterior tibial pulse and in this case I was able to still have a small pulse. So that means there has to be retrograde flow coming from the dorsal side of the foot and into the plantar side. So you can use that to at least estimate. I need to keep those anastomosing vessels intact and my amputation is likely to heal. What about location? So some of these details I guess are pretty important.


    I think the rule of thumb for vast majority of these cases is the length is important. So you try to keep something as long as possible assuming that you're not leaving dead tissue but you are trying to leave as much as possible. Vascular supply, obviously tension-free closure is definitely a good idea and the question everyone always seems to have at least these arguments is how many toes need to go before you go from a ray amputation to a transmet. So my question here is really a ray amputation is legitimate. Let's see what the literature says. I looked at these and I think they are kind of silly. Someone left at just hallux hanging out there. That seems kind of interesting. I have a local personal who builds himself as a vascular surgeon who likes to "leave as much tissue as possible." So he will leave stuff like that one toe kind of hanging out. Fifth ray amputations, there is absolutely no studies that exist for outcomes on fifth ray amputations. If you look at this biomechanically, you remember that the fifth ray has an independent range of motion, so it's going to respond well to an amputation since you are really not affecting much of the foot afterwards but the more proximal you go, the less successful these tend to become. Obviously, you keep the base. You heard Dr. Vito mentioned about the fifth metatarsal base and peroneal. So you don't want to lose those and if you do, remember that peroneus longus is still attached to the foot and if you need to later, you can transfer the longus to the lateral side of the foot and still have a reasonably functioning foot afterwards. How about central ray amputations? There is almost no outcome studies on these. An interesting one is from Dr. Roukis who characterized this percutaneous minimal incision surgery amputation.


    This is MIS before MIS became popular again. So you can see what he did. He amputated the toe. Then he puts an elevator, kind of clears out the tissue around the metatarsal, does sort of percutaneous osteotomy and then removes the metatarsal out of the top. You don't have to worry quite so much about healing. Remember though that if there is a lot of tension on that tissue, it could potentially die often. He did see that as one of the outcomes in this study. He did 17 of these. He had an 82% success rate. That's pretty good. That's actually better than most of the statistics for all amputations, much less a ray amputation. So how about first ray. So to me this is a patient that really kind of tells me a lot about first ray amputations. He is a 56-year-old man. He came in. He had infection. We did acute partial first ray amputation. We get that healed after quite some time. Sometime later you can see that second toe is drifting over medially. It's swollen. It actually ironically didn't have osteomyelitis at the time of this picture but then sometime later this wound healed. He still had the biomechanical deformity. He eventually got osteo, ends up all the way down the line with the transmetatarsal amputation. So what about toe amputation? So the hallux is the one that really kind of maybe more involved with. Retrospective review here of this one, 90 patients you could see that they had high rates of further surgeries and re-amputations, the TMA rate not terribly high. 11% is not too bad. You could see that losing a hallux pretty much brought these patients down in line where they are going to end up having further surgeries and further amputations.


    So they had a high rate of recurrence. You could see why. So this is a different patient. You can see they have three toes. So they are only going to be counting -- oh, there is four. There is one hidden the way. So they can only count to four in that foot but you could see the callus underneath the second metatarsal head, that transfer pressure, that's just going to become a neuropathic ulcer at some point. How about this one? This is a systematic review that looked at partial first ray amputation and the thing that it's important to know about partial first ray amputation research is that all of them define any kind of amputation that includes the hallux, metatarsal head or the metatarsal shaft or base as partial first ray. So hallux by itself is actually considered a partial first ray amputation in the research and we don't consider it that way but generally the research tends to show that. So this systematic review looked at 435 amputations. You could see that they kind of run the gamut of bunch of different types and the patients had pretty high rates of re-amputations and additional procedures. They overall had about 20% chance or one in five chance that they are going to have some other amputation as a result of their partial first ray. This one is retrospective review that looked at 59 patients. They had initial healing in all 59, which is not uncommon for transmet amputation, especially in those who have reasonable flow. Pretty high rate of death after that but if you look at this, 69% of them developed an ulcer at a mean of about 10 months and they went on to higher rates of below-knee and transmetatarsal amputation.


    So that 42% rate is pretty high. So you tell your patient he is going to have a partial first ray amputation. They have a pretty high chance of having something happen to them later. So this one was about partial first ray amputation and their tendency to become transmetatarsal amputations, those additionally had pretty high rate. You are looking at 52% rate turning into transmetatarsal amputation. So the one thing that's kind of hard if you have ever tried to convince a patient who has five toes to be okay with the transmetatarsal amputation, it's not an easy sell. So some of these patients are really going to do better at least initially. They might be okay if you are taking off the partial first ray and then later down the line knowing that something is going to happen, you know their chances are pretty high and you can advise them of that at that time. So partial first ray amputations, biomechanically unsound. The more proximal you go, the more complication rate is there because of that biomechanical problem. These may be good for the short-term but really that high likelihood for future surgery is there. Now could you do a TAL to help relieve the forefoot pressures? That's very possible. Again, no real research to help support us on that question. So RTMA is the best option. I think when you are looking the patient like this, this is a 54-year-old who actually after her transmetatarsal amputation, she kind of admitted like four times for pancreatitis because of her alcohol use. So she came to me already having had a fourth toe amputation. Back in the past, she had a second toe amputation that then eventually became a transmet and she did pretty well after that. I still see her today. It has been about five years or so and she still is maintaining a reasonable transmet amputation.


    What about TMAs themselves? We know that they too have a high rate of revision and further amputations, really the main thing though is for these patients who are ischemic, those patients really are the ones that are going to become the problems for you. So anytime you have an ischemic patient going to have a TMA, you really want to make sure that you have your vascular folks on board. So similar, this is meta-analysis of TMAs. You see this reoperation rate, it's one in four people, re-amputation rate of 20% and major re-amputation rate of 30%. These are not terribly happy numbers for those of us who like taking care of patients like this. So again higher rates of followup surgeries afterwards. So this one is Kaiser over a five-year period with 375 patients. That's a pretty reasonable number. Again, same thing basically one in three chance of having problems. The ones that did were the ones that had nonpalpable pulses in the study. So PAD again is that real enemy that we know. You know these numbers are pretty reasonable. I think if you tell a person they have no pulses, you are going to do a TMA. They have a three times chance of having a below-the-knee amputation. I would tell my patients that. Be honest with them and let them know that their chances are high. I think it will also mitigate your medical legal risk afterwards. If they have renal disease, end stage renal disease, these are even worse just like two nails in the coffin so to speak. You have got an odd ratio of three times more likely to actually pass away within a three-year period. These are ugly statistics, I think. We still have a lot of work to do when it comes to amputations. We think amps are relatively easy surgeries, they may not take as long, they are not reconstruction, they are not glamorous but these are the sickest patients. These are the ones that are going to do really terrible afterwards.


    So I mentioned about length. So length is important and one of the problems it really is the arch of the foot. So if you look at this one that's marked distal, this is an axial view of the distal part of the foot at the metatarsal head. The patient in this has four metatarsal heads, just one of them is a little short and I took a slice from the most distal part. You could see how it's pretty much kind of perpendicular forefoot to rearfoot. But when you go proximal and that's at the metatarsal bases, you have this natural varus position. Right? So if you remove the forefoot, the patient sitting in this natural kind of forefoot varus position. So that's the reason why you really want to try to maintain that length as much as you can or rebalance these later. So keeping the length I think is very important and in some cases you think I want to amputate proximally so I can cover this thing up and close it right away. But with the ability we have to heal wounds, you don't necessarily have to do that. That's what this patient is going to show. So he had a necrotizing infection. We started an I&D. Everything was pretty bad. We converted it intraoperatively to a transmetatarsal amputation. So that's what he looked like initially. You can even see he is sort of starting to roll into adductus but instead of cutting this thing back and turning it into a show part or something, why not just leave it open. We applied a wound VAC eventually. We had to do extra debridement of course as the tissue necrosed a little bit. So that's postop day 21. We are using a wound VAC. We have some other advanced wound care methods that we are using. Eventually, he goes on to heal. So we didn't just jump and make this thing as short as possible, we try to keep it long to allow this patient the most foot. So that's an important consideration.


    So rebalancing is important. The way I tend to see the failures are because of people not taking a thought as to the biomechanical abnormalities. So Dr. Vito really well-mentioned the idea of a deforming force and kind of lost balance. You have to think about these things. The PT tendon is a huge player. A gastroc soleus complex is really important. If you lose the balancing forces, then that's going to become a problem and you want to go back and usually in a stage fashion you can take care of that. So this is that same patient. You can kind of see preoperatively. He has kind of varus position. He has an inverted heel. The forefoot is inverted to the rearfoot. I wouldn't want to have him walking on that. I have seen all kinds of lateral plantar ulcerations as a result of that, so we really want to rebalance this. So what I did was choose a percutaneous Achilles tendon lengthening, tenotomy of the posterior tib, not a transverse just tenotomize the whole thing. You could do it through a very small incision. I take a chunk out so I don't have any chance of it coming back. Then I did a tibialis anterior transfer. For me personally, I am not much of a split tib-ant transfer person. I really would prefer to do the tib-ant all the way completely. It's an easier surgical procedure. You are working with a lot more. I don't have to worry about any varus and you could see he is pretty rectus there. So this is comparing his preop and his postop. He is now walking and doing just fine. It is nice balanced and he is not making calluses. So for me, that's the main thing I am looking at. After they recovered, if I am seeing calluses, I know that there is something going on that we have to address.


    So some last words. This comes from the literature. It's not necessarily stuff that I had been doing but honestly in preparation for this lecture, there is some pretty good ideas out there that some folks have. So this one is from a study from Japan and what they did was they do their transmet amputation but if possible they are keeping the intermetatarsal arteries, so it's kind of plantar arteries there. They are maintaining those and they are getting -- this study showed pretty good results. So you're not just stripping out everything and just leaving as much of that fat as you can. You are actually trying to keep the vasculature the best you can. The other one of course is the direction that you caught your metatarsals. We all talk about a parabola and that's a very important of course but if you were to cut 90 degrees to the metatarsal, you are going to end up with a corner that the patient is going to walk on. I see plenty of times where patients have those problems. So if you look at the person and if they have -- you kind of want to make that cut parallel to the weightbearing surface -- if they are a cavus patient, you are going to change the angle of that obviously because your met declination angles are a bit steeper. So you are going to drop your hand more for that patient. For the planus ones, it's a little less important and so that makes it -- you want to make sure that you don't end up with a corner on the bottom. You really wanted to distribute that pressure out. Extra skin is good. One of the things we tell all of our residents is once you cut it away, you can't put it back on. So when you are doing your amputations if you have extra skin, just leave it while you are doing your amputation and then remodel your flap afterwards. So this one is sort of hallux digital fillet flap where we keep the lateral skin of the hallux and then you can flap it down and you have got a lot of extra tissue instead of removing that in a typical fashion and then having nothing to close it with. So use that extra skin.


    This one I found kind of interesting. They drilled the hole into the metatarsal. They used the 0.54 K-wire, so they made really small holes, so you're not going to destroy the metatarsal base. And then they ran suture from the plantar skin up into the hole around the metatarsal and back out. So this is sort of like creating a horizontal mattress that's kind of directed plantar ward. They are doing that to anchor the plantar flap and this study actually advocates putting the patient in a cast and letting them walk. Now, I'm not going to advocate that. I read this article. I thought these people must be crazy to walk a transmet amputation on day 1. So I wouldn't suggest that. But what is nice is that by anchoring that plantar flap, you are really preventing a lot of motion and you are allowing that incision to heal with a little bit less tension. So I thought that itself was a pretty good idea. So bottom line here, amputations can be initially successful but they do have a high rate of complications. You have to let your patients know about that. Keep the expectations low. You are saving their leg or their life. You're not trying to get them back to becoming Olympic athlete. PAD and renal disease, good luck, if you have -- you learned a really great way to treat these patients and have your amputations be successful, come tell me about it, I want to hear it. More distal the better and then rebalance these patients when possible. My best suggestion to you is to wait, let everything heal, calm down, rebalance them later. I have tried to do it acutely and the patients generally don't do well. Sometimes you are going to make an incision through skin that was recently infected and that skin is not the same. It's something that sat around for quite some time. So from there, I will say thank you very much for your time and your patience. I appreciate it.


    TAPE ENDS [30:01]