Section: CME Category: Surgery

The Knife Vs. Gravity: Surgical Offweighting the Diabetic Foot

Jarrod Shapiro, DPM

Jarrod Shapiro, DPM discusses the pathomechanics that contribute to the development of diabetic foot ulcerations, reviews current literature that discuss contributing factors that aid in diabetic foot ulcerations, as well as discussing surgical planning to give patients the best opportunity for them to heal their wounds.

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Goals and Objectives
  1. Review the pathomechanics for the development of diabetic foot ulcerations.
  2. Review research articles that discuss numerous contributing factors that play a role in the healing of diabetic foot ulcerations.
  3. Compose an appropriately planned surgery to increase chances of wound healing in the diabetic population
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  • CPME (Credits: 0.75)

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    Release Date: 01/14/2019 Expiration Date: 12/31/2020

  • Author
  • Jarrod Shapiro, DPM

    Associate Professor, College of Podiatric Medicine
    Western University of Health Sciences, Pomona, CA
    Associate Editor PRESENT Podiatry Online

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    Jarrod Shapiro Dr. Shapiro has nothing to disclose

  • Lecture Transcript
  • TAPE STARTS – [00:00]


    Speaker: We have to recognize the importance of deformity and I think -- remember in the [00:00:07] [indecipherable] slide from the paper in 1999, we had that critical triad, neuropathy, deformity and trauma underlies 63% of causal pathways leading to ulcer. I think it's more recognized now than ever that surgical offloading is oftentimes key to not just healing ulcers but preventing new ulcers because high plantar pressures, in the presence of neuropathy, lead to ulcerations, very important risk factors. Now, 30-40 years ago, this was not the case. Luckily, we have learned a lot about diabetes, neuropathy, microvascular disease, and macrovascular disease and we can better assess the appropriate time for intervention if the intervention is either elective or prophylactic. So a very important topic is surgical offloading and we have asked Dr. Jared Shapiro to make his return to this stage to discuss his thoughts on this very important topic. Jared. Let's welcome him.

    [Applause]

    Jared Shapiro: Good morning everybody. So first I have to say that it's a true honor for me to follow Dr. Frykberg. I mean to follow one of the leaders in our field is for me a true honor. So thank you very much for having me. My slide here looks like something from Nascar, so I apologize for that, but I am also here representing ACFAOM, which is the American College of Foot and Ankle Orthopedics and Medicine. We are the academic arm that goes along with the American Board of Podiatric Medicine. So just like with ACFAS and ABFAS that is us with the medicine board. So we are doing some good things and I would invite you to come join us if you haven't.

    [02:02]

    So I am going to talk a bit about surgical interventions. I am going to make some arguments for you and some of my arguments will overlap or piggyback off of what Dr. Frykberg was talking about and so I will try to sort of move through those relatively quick to see if you don't have to listen to the same thing again. So my overall argument here is that in many cases surgical intervention is maybe your better choice for large number of your diabetic patients and I am going to make this argument. So definitely a challenging patient population. I think that was made pretty clear just now. Nonsurgical doesn't equal conservative. We always mention the two is as if there are conservative equals nonsurgical. If you do rational or thoughtful surgery and approach the patients well, then that surgery is pretty safe. These are very high stake patients and then maybe if you comment on the future of this. So again, this really kind of follows what Dr. Frykberg was talking about. We have a bunch of different places that we can prevent amputation from occurring and each one gets a little harder the further up you go. We could try to prevent the ulcer from leading to the amputation. We can prevent the localized trauma from becoming an ulcer. We can prevent the pressure somehow from leading to trauma. We can prevent the deformity from causing pressure and of course we could prevent the patient from having neuropathy but that one is probably the hardest one of all. So as we go, the interventions that we have to do are increasingly more problematic and more difficult to respond to. So here is the first one.

    [04:00]

    My first argument here is that this is a very challenging patient population and you can't just sit back and wait for that ulcer to heal. So we know there are very high number of sick patients. We know that likelihood of ulcerations are very high. We know that non-compliance is the rule and in many cases education really doesn't do the trick as far as preventing future amputations from happening and future ulcerations. So again, some scary statistics. The large number of diabetic patients worldwide, a lot of comorbidities. These are very complicated patients to deal with and we are all really dealing with these. They have many of these kinds of issues. And then as age goes up of course these complications become worse and results of these end up being more high amputation. So 15% or so are going to develop and ulcer at sometime, 2% to 6% maybe yearly. These numbers are probably even higher. These numbers are not the newest. So even higher, so this is a very high risk patient population. So pressure in callus, of course Marie [phonetic] here was kind of first to show that the pressure of the callus will predict the future ulceration. Where this callus comes from? It comes from deformity. So shear is also important. We talked about peak plantar pressures and those type of things, but don't forget that shear is also an issue. So this one can be a significant risk factor and increases the peak plantar pressures. This is correlated with them at a much higher rate. So pressure and shear are really significant issues we have to worry about. So here is an example. Neglected plantar pressures, you know, the obvious callus. This is something we all see in practice, all too commonly. When I am seeing patients -- when I doing my physical exam the first thing I really look for is that if there is a callus. The callus is really saying this is where the pressure is.

    [06:02]

    There is a deformity. You know you can use all the expensive pressure devices that you want but the callus is I think that's going to really tell you where you at. So pressure obviously is important and unfortunately we don't have a true cut-off. We can't say that you know a certain peak plantar pressure is going to lead to an ulceration. Armstrong did some good work and found that the higher you go, the greater than chances of there becoming an ulceration as a result of that. So there is an optimal cut-off. That would be great. This would be like blood pressure. 120/80 is prefect, anything higher is not good. We don't have that. What we do know though is again the higher the pressure, the worst it is and pressure is coming from deformity in most of these cases. So we see these all the time. All the pretty obvious things that will cause deformities to occur, you know hammertoes, abnormal metatarsal parabolas. Equinus of course is a pretty significant player on this. Same thing with other types of deformities. Limited joint mobility, we have -- you know adding sugar essentially to the different parts of the body causes stiffening. Intrinsic muscle atrophy. These things are all causing extra problems that weren't necessarily there in the non-diabetic patient population. Here is an example of that. Pre-ulcerative change in the patient, pretty common. You can see that contracted third digit. This is that pre-ulcerative change. We managed to catch this right before it turns into an ulceration. So as Dr. Frykberg mentioned deformity, PAD, diabetes, neuropathy, this is a very bad combination. You could see this patient with gangrenous changes even extending some necrotic changes into the arch and interdigital space with gangrenous changes.

    [08:04]

    This is a patient who presented to me like this. He walked in our wound clinic with this type of presentation. So this is a really super high risk patient. You can't just sit back and think this is going to heal on its own. So this is how he ended off with TMA after revascularization. So what about education? So the data that we have isn't great. The Cochrane Review back in 2010 did look at these studies and they looked at 11 randomized controlled trials and four of those examined ulcer in amputation outcomes. They had mixed results about whether education will actually help to prevent wounds from occurring. Most of these studies were found by the Cochrane in collaboration to have poor methodological quality. If you look at the Cochrane collaboration, it's kind of funny because almost every study that they do seems to come out with some poor methodological issues but especially ones that pertain to the lower extremity there are oftentimes problems. But what is shown is that they mentioned that there was insufficient evidence to show that education alone will reduce that ulcer or amputation risk but three or four of those studies showed in general that education doesn't prevent amputation from occurring. So there is a whole variety of reasons why that would occur. Educated patients who knows nothing about medicine, about ulcer prevention and then in you are five minutes that you have with them and then have them leave, understand everything you have told them that they need to check for all these particulars signs and then not end up with an ulceration. That's not easy to do. The thing I have noticed is that I have gotten a little bit more experience and practice is about noncompliance and this was really brought home to me by Armstrong's article where they looked at the compliance rates of patients.

    [10:05]

    So this is a perspective longitudinal studies. Only 20 patients and not a large kind of studied. They put a pedometer on their hip and a removal CAM walker on patients with ulcers. They had them wear it for seven days. They found that 28% of their walking activities were at home when they wore the CAM boot. So only basically one in four patients kept the CAM boot on. Of those patients who did keep it on, those were only 60% of the time that they actually kept the CAM boot on. So this one really kind of showed that noncompliance with removal devices is really very common and something that we are dealing with. In our office, they tell us that they are doing everything we ask and then they go home and they take off their boot, their post-op shoe or whatever offweighting device you have and this is what's happening. It sounds great in your office and then they are doing all the things they are not supposed to do. So a similar study here by Armstrong, same kind of 20 patients. This is a different group. These were patients with deformity and neuropathy or a prior ulcer history and these were patients that they wore pedometer and this was with shoes. So 85% of their patients wore the prescribed shoes when outside the house, but 15% wore them when in the home and they were instructed during the study to wear the shoes in the house. Because if you are walking more in the house, you are more likely to ulcerate and have this complications while they are in the house as opposed to walking outside. So what I have seen from this and this really kind of goes along with my practice has been that noncompliance is really the rule and not the exception. So what we do for patients will have to keep in mind that these issues are really there. So here is my next argument.

    [12:00]

    Nonsurgical doesn't equal conservative therapy. We are going to talk about a couple of studies that showed some comparisons and we are going to talk about some methods that essentially removed the patients and what some of the researcher have shown. So this is way back in 1998, 20 years ago but this was a perspective randomized trial. They looked at surgical and nonsurgical care for forefoot and digital ulcers and they had these patients followup for six months. What they found was, of the ulcers that received the conservative care, which was kind of back then this was wet-to-dry dressings, it wasn't really what we will consider the standard of care right now. But they received conservative care and 79.2% of them healed but you can see there is 128-day healing time of these patients who received surgery, 22 of this number have received surgical care and 95%, almost 96% had healed and the time to healing was almost three times less, so much faster healing and the recurrence rates turned out to be lower as well. So again for me, the biggest flaw with this was that their conservative care really differed from the current standard of care. So I would expect at least some improvement in those conservative or non-surgical numbers, maybe somewhat but I think even standard of care doesn't get you to 96% of healing. So Armstrong looked at fifth met ulcers and they did a retrospective study where they compared patients who had gone through surgery for fifth metatarsal ulcer. This was a fifth metatarsal head resection and they compared those to a conservative group who had local care, which was a moist wound care and offweighting.

    [14:00]

    So what they found -- if you kind of see this is a little small but the healing time for the nonsurgical group was 8.7 weeks versus 5.8 for the patients who went through the surgical approach and the recurrence rates were significantly lower. Now, granted this is a relatively small number of patients, we are not talking about thousands here, but I think these numbers are kind of striking. Really looking at a much lower six-month recurrence with patients who underwent surgical correction. So Armstrong has done quite a bit of work on this and this is another study that looked at total contact cast, removable boot and half shoe to heal ulcerations. So this one was a perspective randomized trial of 63 patients. This is what they found, so with the total contact cast, they had 89% of patients healed, 65% if they had a removable boot and 58% if they wore a shoe. So the one thing that's different between the total contact cast and the others is that it's not removable. That's pretty obvious. I love this quote in his paper was that this created the ability to force compliance. I think that's hitting the nail right on the head on this. It really does force compliance. So if you are removing the patient as a factor, then you will have a greater chance of successfully taking care of this. So here is a case provided by Dr. Kathy Satterfield, one of my partners over at Western University where they sort of removed the patient with a TAL. So you can see this patient underwent quite a bit of treatment down there at the bottom, wasn't healing. So they do tendo-Achilles lengthening and they do go back to the local wound care. So here you go two weeks later, the patient is resolving and at four weeks, you have healing and that's kind of going along with some of the other studies as far as the timeframe.

    [16:07]

    So this patient underwent a TAL and removed those peak plantar pressures in that area and this patient healed. So diabetic patients are definitely not the healthiest people around. So we want to make sure that we are doing a rational surgery. I am not advocating that you take every diabetic patient and do a fifth met head resection or fix a hammertoe or something like that. But if you think about what we can do to control or mitigate those complications, then you will be in a much better shape. So let's talk a bit first about anesthesia. So Kadoyo [phonetic] study looked at a large number of patients and they found that overall complications increased with those patients who had autonomic neuropathy and that's pretty clear. So general anesthesia would be considered risky but because we are the end of the limb, we have some nice alternatives, right? So A, they are neuropathic and so sometimes they don't need anesthesia. I freaked my anesthesiologist out plenty when I tell them I don't need any medication. The patient can be wide awake and we can do some of these surgical procedures and they are fine and they don't have pain. But local anesthesia works really well. Popliteal blocks worked very well for these types of patients if you have a concern and the patient can essentially be wide awake for somewhat smaller procedures. Obviously, for something like Charcot reconstruction or tibtalocalc fusion. That's not going to work for just straight local for four-hour procedure. So what about infection? We are always worried about infection. That's always a significant issue. The chances of infection are definitely higher with patients. [00:17:50] [indecipherable] looked at a large number of patients in his thousand procedures. He found that neuropathy increased the risk of infection in those patients with diabetes and diabetes.

    [18:02]

    Make sense. If you are walking around on your wound after surgery and it doesn't hurt, then you kind of get an infection. So the odds ratio was about two and half times that if they had a prior ulcer. So what about Armstrong and Lavery study. They did a smaller one, retrospective case control study that looked 31 diabetic and 33 non-diabetic patients who underwent surgery. These patients with neuropathy and prior ulcer had an increased risk of 14.5 or so percent. But they did not have any wound healing problems. So if you keep in mind that the patients are at higher risk, then you are going to do your patient a better service. You don't necessarily take them back to surgery. Also keep in mind that these studies really warrant looking at hemoglobin A1c levels. If your A1c level is around 7 to 8, the chances of infection and skin healing issues postoperatively are much lower. So if you are going to take a picture with an A1c of 10 into surgery, you should anticipate that they are going to dehisce and they probably are going to end up with an infection. Nutrition is always an issue. Protein calorie malnutrition is very significant regardless of whether these patients are obese or not. So ordering your albumin and pre-albumin are important. You can help to use some of these older kind of classic studies. They looked at albumin levels and these were predicting survival and success healing rates in patients with signs of amputation. So sick patients, nutrition becomes important. Think about that before you bring your patient in. I think I am probably pitching to the choir if I tell you to check pulses and make sure that the patient has appropriate optimization of blood flow. Obviously, TCPO2s and pulse pressures are important. Sending them to your vascular surgeon if necessary or your interventional cardiologist, any of those numbers of people on the team, this one is of course necessary beforehand.

    [20:10]

    So don't do your surgery without that of course. So if you understand the patient and their risk factors, surgery is relatively safe. It's not horrible thing that you cut on a patient and they are going to end up with infection. Besides, they have a wound. It's like grand central station for bacteria. So they are going to get infected anyway. You are just making another wound along with the first one. So optimize your healing potential, consider a local and regional anesthesia to prevent the general perioperative complications and then make sure you are monitoring them really closely. So I tend to see my diabetic patients who have had surgery. I tend to see them about three days after surgery watching really just to see if they have an infection. I tend to see them a little bit more than my general elective patient, which is about a week postoperatively. It's also effective. So okay, maybe it's safe. This is a high risk group. It's just really better versus doing nothing, doing no surgery and just staying with the sort of "conservative therapy." So we will talk about a couple of examples here. So here is an example of a patient of mine who I took care of relatively recently. He had a tibial sesamoidectomy from prior surgeon that was for this neuropathic ulcer in the planar surface of his foot. He has a cavus deformity. He has equinus. We finally get him down to an A1c of 7 and we bring him into surgery. We can see the little lesion marker as to where the ulcer is and he has a tibial sesamoid already removed. So here is kind of pre-op and post-op.

    [22:00]

    So all we did was a dorsiflexory Lapidus type of procedure, dorsiflexory first TMT fusion and we did a gastroc recession. I didn't try to fix this cavus foot. I didn't do anything like that. He didn't have Charcot. There wasn't a Charcot reconstruction. But all we did was remove the pressure from the plantar surface of first metatarsal head. A small amount. You can see this is a subtle difference. I am not trying to elevate it so much that we end up with new callus into the second metatarsal head. So simple kind of thing was effective in taking care of this patient who really wasn't healing that before. So equinus of course very significant. We know this is an important factor for diabetic patients with glycosylation of the tendon. Lynn's article was one of those kind of classic ones where they looked at patients. They had 93 neuropathic patients with diabetes. They had total contact cast treatment. Some of them went through total contact cast. What they found was decrease in dorsiflexion of course and also with plantar flexion. So group two in this study then underwent a TAL procedure and they were followed with total contact cast. So all of those healed except one, so they had 93% success rate, that kind of goes along with the success rates of the other ones, the other study that we are talking about. So four of the ulcers were occurred in group 1 and none of those occurred in group 2 and that's pretty important because you know the recurrence rates are very important. So by removing that equinus and increased peak plantar pressures, they decrease their recurrence rates. So correction with percutaneous TAL was shown by this to be effective.

    [24:00]

    I am not so much a total contact cast person anymore as I am an instant total contact cast. Armstrong has done some really nice work with that. You just put the patient essentially in a CAM boot and you lock the CAM boot in with cast tape. So you cast the CAM boot. If you haven't done that before, make sure you put some Coban or something underneath it because when you the cast tape on, it will destroy the rest of the CAM boot. And you want to be able to use the CAM boot again. Patients generally like this in my practice better than they like just a total contact cast. The time for this is much less. I can train my staff to do this much easier instead of -- I would never let one of my staff put on a total contact cast. I would only do that kind of thing myself. So there is some benefit to that. So Miller study I think probably we all know about. They looked at patients with diabetes and neuropathic ulcers, 64 patients, same type of study as Lynn's where they put them in a total contact cast and then to TAL. Here is the difference. Again same kind of thing. You can see that the two-year recurrence of those with total contact cast was 81% and those who had undergone a TAL was 38%. So really signification difference in the recurrence rates. What they found, which is kind of interesting was that the patient's returned their peak plantar pressures back to their preoperative states within that seven-month period, but they still maintained that low recurrence rates. So that was good to see. Even though the pressure seemed to be coming back, there is some difference in function afterwards. So here is this patient again, I kind of showed you before. After he was re-vascularized, he had a TMA and TAL. He did great. No re-ulcerations. There is a plantar surface of his foot.

    [26:00]

    That necrotic care on his arch after just local debridement was easily healed once he was re-vascularized. So a successful patient who walked in basically to our clinic never having had any medical care previously, got his diabetes under control, was re-vascularized, had a team approach and he did great. So this is a patient of mine sometime back who you can see, she has got HAV and some other digital contracture issues. She has this shear ulcer on the plantar medial side of the first metatarsal head and we were concerned about doing surgery on her foot, so we did a gastroc recession. I do gastroc even more commonly now I think than I did before because I can weightbear those patients immediately after surgery. They like to walk. So this patient completely healed within four weeks of having her gastroc recession. Very small ulcer, easily healed but just by removing that equinus contracture, this patient eliminated that shear force and healed and didn't recur after two-year period. So this is the stuff that kind of overlapped what Dr. Frykberg was talking about, so I am not going to bore you with it terribly, but we know the odd ratios for amputation are very high for patients. We know that the non-traumatic limb amputation rates are incredibly high. There are plenty of data that shows that these patients are significantly at risk and I think it requires a much more aggressive approach to these patients. This is basically the same slide that Dr. Frykberg was talking about, the same study. This was from Armstrong's paper and if you are treating somebody with cancer, you try to resect it whenever possible. That's pretty much as standard of care. If you consider patients as essentially having a malignant diabetes or almost similar to a cancer, then why not treat it aggressively if that's at all possible.

    [28:01]

    So there are of course a lot of procedures that you can do. I don't think I need to go into how to do a met head resection or fix a hammertoe. You guys all know how to do all that kind of stuff, but there is lots of different way you can take care of this. The details are probably less important than the fact that it's better to be somewhat more aggressive about taking care of these patients. So there are lot of questions that still remain for us to answer. So questions such as, is there a window for prophylactic surgery? If you have a patient who comes in and has never had an ulcer, they have a callus and a deformity, should you take of that surgically beforehand before they have a chance to ulcerate? We don't actually know the answer to that. I think that's a very difficult study to do but that would be kind of need to see. So we don't have that quite yet. So bottom line here, this is an ultrahigh risk patient population with a lot to lose. Treating them nonsurgically may be actually a more radical approach. I will give you the examples simply of a person with an abscess. Do you leave an abscess alone and put them on IV antibiotics or do you actually go and do an I&D? I think the I&D it would be the more conservative surgery and just giving somebody antibiotics would be the more radical or foolish approach. So again appropriately plan a surgery. They are safe and effective as long as it's in the right patient at the right time. The complications are really considered serious, so these patients really need aggressive treatment and with that I will thank you very much for your time.



    TAPE ENDS - [29:40]