Lee C Rogers, DPM discusses the risk factors that lead to diabetic foot amputations, advanced imaging modalities to assist surgeons with debridements and amputations, as well as the benefits of Negative Pressure Wound Therapy (NPWT) and skin grafts as adjuncts to wound healing.
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Lee Rogers has disclosed that he is a consultant/speaker for Sanuwave, Kerecis, Advanced Tissue and is and officer/director for RestorixHealth
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Speaker: I am going to present now before the break on partial foot amputations now what. And one of the interesting things is that you know and I see this often when I speak with Chuck Anderson. And I don't know why but I feel like our approach and our practice is so similar and I have got a lot of the same -- similar types of cases with using Luna or Spy to help determine the extent of amputation or what revision might be necessary but it's also refreshing to see that from around the country to have similar type of practice and similar type of success. One of the reasons why amputations are so complicated, partial foot amputations, is because when we look at the risks for wound complications after surgery and we consider our patient population, a lot of these patients have a lot of these problems that are the major risk factors for wound complications. And so we are dealing with some of the most complex patients at risk for non-healing after these types of interventions. So we all probably have heard of the wound reconstruction latter where when we are trying to get the wound to heal, we start out with simple to more complex. We can let the wound heal by itself, which is secondary intention. We can do something little bit more complex, primary delayed, primary closure using skin stretching devices, putting skin grafts, flaps and there is random pedicle or free flaps using tissues and matrices that are kind of fall under secondary intention. So we are familiar with that but I want to propose something a little more focused on the amputation.
So how to get the partial foot amputation reconstruction latter, let's say. So it's starts with having an amputation, partial foot amputation. Then we need to make sure that the infection usually either infection or ischemia is the reason for this partial foot amputation so that we have managed a skin and skin structure infection or the osteomyelitis that the ischemia is being managed and this patient is being re-perfused that we are still taking the pressure off the foot or the incision where it to be an amputation. Perhaps at this point, we are temporizing this with negative pressure but then we can consider going from simple to more complex or maybe desirable to less desirable in covering these partial foot amputations. So something you know maybe we look first at -- can we get this to close with delayed primary closure, maybe some bone resection delayed primary closure. If that's not possible, let's say, maybe there is bone or tendon exposed or just a deep wound where we are using negative pressure to fill this wound in. Are we covering bone or tendon at this point with either some type of plastic surgery or cellular tissue based matrices? Then once this has been leveled and granular, are we moving now to using skin grafts or do we need to perform a more proximal amputation in order to get this to close? So we are going to just go over some techniques that may be not in order but some techniques that will help us with steps in this pathway.
So I said this yesterday but this is especially important after a partial foot amputation as I just said in the previous slide that usually infection or ischemia are the reason for the amputation and perhaps if it's infection, the ischemia has been managed yet but these needed intervention should not be delayed and time is tissue, so we need to be working closely with our vascular or interventional colleagues to restore perfusion. So we might be after this -- and some of these cases -- they are demonstrating techniques or tools, they may not be on partial amputation, maybe just on wounds but it's the same process or idea applies. But one of the things that we need to do is make sure that this wound remains clean and free from infection. We might use things that provide advanced debridement like this is ultrasonic debridement that helps to lyse bacteria and irrigate the wound, remove any fibrotic or necrotic tissue and we can take a wound that looks like this with some hyperkeratosis and little bit of necrosis and fibrotic tissue around and in the same setting, remove the bad tissue but leave behind the good tissue. So this type of debridement is more discriminatory for unwanted tissue. So this is a little different than what Dr. Anderson was presenting on determining the viability of the flap but we also are using Luna, which is a type of vascular imaging to determine the extent of the debridement necessary because we may not be able to visualize. You can obviously see there is gangrene here. There is some gangrene and fibrosis here.
But what of this is going to survive and if we just use you know -- if we just remove what is gangrenous or visibly unhealthy, the other parts that is converting or already perhaps ischemic or dying, we might leave that behind and it might result in then subsequent infection or subsequent surgery that's needed or just increase the amount of time that it takes to get this to heal. So we are using Luna to help determine the extent of the debridement that's necessary in cases like this. And this is as Chuck mentioned there is an IV injection of dye. This is just anesthetic there. So I mentioned that because we are just doing an ankle block. Can you turn the light down just for a moment? Are the switches in the back -- because it makes it -- it's a lot easier to -- no, no I said the lights on the -- turn the lights up here down. I noticed this in your presentation, Chuck. It's lot harder to see. These things are so dark when you are showing Luna videos, it's really hard to see in the back. Don't go anywhere, Steve because it only going to be 15 or 45 seconds. Alright, so here, this is the same foot, toes are here, the heel is here. We saw that the second digit was gangrenous. This is right after injection of dye. It only takes just seconds for this to perfuse and so now visually we are seeing everywhere that this dye is able to penetrate.
This area right here I noticed that this area which visibly looked okay is dead. There is no blood flow getting in here. So now I am taking a skin marker and since this is things that I can't see visually, I am taking a skin marker, I am drawing around the area that needs to be resected and getting a better idea of what's salvageable and what's not. And then I used my kindergarten skills and I cut in between the lines and remove everything that the Luna predicted to be dying. And then I have the opportunity to then repeat the test and ensure that the margins are well-perfused. What you see here is a lot of bleeding that has occurred from this debridement and this old blood that didn't go back through the liver and have the dye excreted, so you are seeing the remnant of dye here but now are looking at the rest of the skin and I am paying particular attention to the periphery to make sure that the edges of the skin are well-perfused. And you can see some of the parts should I look at here, I may test for cap refill to you know because maybe it looks fine but I am just testing to see if there is good perfusion. And then I know that I have done my adequate debridement. You can turn the lights back on now, thank you. One of the techniques that is very useful post amputation is using negative pressure and actually this article, lead author is David Armstrong, looked specifically at this. The negative pressure wound therapy after partial foot amputation in a multi-centered randomized controlled trial. I think it's actually the largest VAC study been published to date.
And not only does negative pressure in a post partial foot amputation group lead to better closure than standard of care, which in this case was wet moist dressing, but if you look at the rate and the amount of granular tissue that forms after using negative pressure in this group, the time, this is the days that it took to get to the top quartile of granulation tissue. So the number of days it took to between 75% and 100% granulation tissue. These patients are getting to that level of granulation tissue much faster than the standard moist wound dressing group are. And that really is just helping you move to the next step. I know that in the old days, we used to think about some of these devices like one is VAC. VAC stands for vacuum assisted closure and these devices, I don't believe, are really in of themselves are something that should be thought of bringing the wound totally to closure. Instead it should be thought of as shortening certain timeframes in the wound healing algorithm and one of those timeframe is getting 100% leveled granular tissue and certainly negative pressure helps you with that shorten that timeframe and this shows that. That shortens the overall wound healing timeframe. And then looking at secondary amputations after in the group negative pressure versus standard moist therapy, a lot fewer secondary amputations that were performed. Here is other studies that are looking at the amount of granulation tissue when using negative pressure and showing that over 16 weeks, the negative pressure group having a lot more granular tissue in percent than the standard moist therapy group and then looking at the overall healing rate of course as well.
But then also looking at the incidence of amputation afterwards because we are trying to limit the progression of distal amputation moving more proximal in negative pressure far fewer than in moist wound therapy. So the military has a lot of experience with using negative pressure to temporize these wounds, these traumatic wounds. And I think we can learn a lot from that in the diabetic foot in temporizing some of our diabetic foot wounds. So we aren't ready to be closed yet. We need a few days to work out the perfusion. We need some more time to work some other things out, schedule surgery, have some surgical planning and I think that VAC helps to provide not only a obviously good healing environment but it helps to separate that environment from the rest of the dirty environment that patient is currently in, which is the hospital. And so you are providing a closed clean environment versus having multiple change this dressing over the course of several days to look at the wound exposed every time and that in my opinion increases the risk of infection probably [indecipherable] [00:13:26] hospital acquired infection. So when we look at comparison across trials with negative pressure, these were for the major trials that were done looking at the healing in the active group versus controlled group, so active group is light blue, controlled group is dark blue. And then the wound size and all of these different studies, you can see the wound size in this one, well this was the study that we just showed the [indecipherable] [13:56] study. Those wound sizes are obviously a lot bigger in centimeter squared because they are post-amputation wounds versus some of the other studies that were done that were not post-amputation wound and wound duration.
So we can see that it really doesn't matter the size of the wound that you are getting an equal amount of improvement in wound closure versus smaller size wounds. And people sometimes will ask the question, does it make a difference whether I have an acute wound or chronic wound and the response to negative pressure? So here we have negative pressure versus standard wet therapy and standard moist therapy in acute wounds and you see the separation of this line here. So it's a wound survival plot. You don't want your wound to survive. So it's kind of backwards thinking. You want your wounds to die that means the wounds are healing. So down here, we see that the more wound are healing. In the chronic wounds, more wounds are healing here than in the moist therapy, the controlled group. So we take this blue line and this blue line and overlap it on the same graph of time and we put them together, so now we have acute, which came from here and chronic, which is blue line that came from here. And you see that really it doesn't make any difference whether your wound is acute or chronic. It responds exactly the same way to negative pressure over time. The nice thing about negative pressure and this is very important in the post amputation phase is that you can combine this with good offloading. So in this case we can combine it with total contact cast and you can use some pre-made dressings now that help to keep the track pad and the bridge and the hose out from the plantar surface of the foot. There are a lot of benefits of using negative pressure on closed incisions and I think that -- so we have an increase in skin perfusion.
It's not really meant to be used for drainage. If you need a drain, you are going to need a drain. You don't put negative pressure for drainage and you definitely don't want drainage coming through the incision. I think probably the largest reason why this works is incisional splintage and this is because when you put foam over the top of the incision, you have adhesive here, you have adhesive here and you put negative pressure on this and it all sucks down and closes together. Now, it's not going to move, so one of the more common complications and risk factors leading to dehiscence is that you have this motion that occurs at the incision site and so there is no motion that's going to occur at this incision site because of the negative pressure holding everything together with the adhesive and the foam under negative pressure. This creates a closed wound environment again separates the wound from the dirty hospital area where the patient is. So when you look at some of these cases, this is partial calcanectomy. Obviously had a necrotic and osteomyelitic complications here. So have to be revascularized but we also had to remove this osteomyelitic bone. So here we have a partial calcanectomy. We created our flap here. We are going to close this but these are very complicated wounds and especially if they are also performed in the presence of renal failure, study that Bob and I did -- actually my very first project I ever worked on was project with you looking at the risk factors for failure of partial calcanectomy or just reporting on large group of partial calcanectomies.
And what we found was the largest risk factor for failure was patient that was renal failure. And so this is a very complicated and risky incision and one of the ways we can improve our incision healing is by using negative pressure to splint this incision and improve the perfusion to that incision and ultimately get healed. So this is really the old way of doing it where we are just creating our own incisional negative pressure. Now, the new way of doing it is using an entire system that's already designed to be placed on the incision itself. When you do it the old way, you generally are taking a very small line of either Xeroform or silicone and you are putting it over the incision line. You are taking the drape of the adhesive and you are putting it really close to the incision line because you don't want foam touching any intact skin because you'd macerate that. And so the foam really isn't touching anything except the Xeroform or the silicone and then you put the other drape over the top of it and that's why you are getting this splintage in this immobilization of the wound edges. In the case of some of these systems that are already designed this way, it's just a peel and stick dressing. The entire dressing you just peel the whole thing off. It's already contained all in one and you stick another foot and hit the button you turn it on. So it's really no design or fashioning of this. So in this case, this is a TMA, also another risky incision I think in the diabetic foot. So here we have the finished TMA but then applying this peel and stick dressing and turning it on. These things are disposable.
It lasts about seven days and really with incisional negative pressure, you don't need much more than five to seven days to improve your take. So here is another example of TMA and then five days later here. You don't have to use that particular device. You could also use other disposable negative pressure devices and now there are lots of them that are on the market and but again you have to create your own dressing that goes over it to prevent any maceration or skin complications. Now, we have a wound that let's say there is either exposed bone or exposed tendon. We want to get that to be covered. These are all the -- they are not all the cellular and tissue based products that are on the market but these are lot of different categories of cellular and tissue-based products. This tells you what their FDA indication is for and then it also tells you what kind of FDA approval they had and how many randomized control trials there were. And I put this graph together about the year-and-half ago, so if there is anything new, I haven't included that in here. But we have got two products that we're very familiar with but these products are generally not used in the operating room. They are used in the clinic setting. Their indications are very narrow because the way their approval went through the FDA, they are prior-market approved. They are only approved for diabetic foot ulcer and venous leg ulcers or for diabetic foot ulcer. Do have a lot of evidence around this because of the nature of their approval because it went through FDA this way, they had created a lot of evidence for this. Now, we have a few products that are 510(K) approved and this means they are just close enough to predicate device that the FDA says, okay, well, we will use their efficacy data.
We just need you to do some safety data and these products are approved for partial and full-thickness wounds. And that could include all the way down to bone or tendon and certainly if they are not specifically indicated for that, you can use them off-label as a surgeon to cover bone and tendon in order to get granulation tissue over them and at many times they are doing it in combination with negative pressure. But two of the more common ones I see or probably even three of the more common ones I see over bone and tendon are GraftJacket, Integra, KeraSys, also EpiFix in some cases, I will show you that. So this group of products right here are 361 approved by the FDA and that's a category of approval that means that it's human tissue and you know when you take a kidney out of one person and you put it in another person, you don't need to get each kidney FDA approved. FDA says well, it's human tissue, it can be used supposedly for homologous use in another human. And so it's very easy pathway. That's why you see a lot of amniotic tissues that are coming to the market now because it's not very difficult to get the market. But they are approved for acute and chronic wounds in these cases and that's a pretty broad indication. It's not an FDA indication because FDA doesn't give indications for this. The FDA just says you can use it on humans. So they use amniotic tissue for pterygium of the eye, for gingival retraction, for all sorts of things but the indications and what we were doing for acute and chronic wounds, it's pretty broad of any depth and any duration. So here is an example of -- we had a partial calcanectomy here, some bone debridement.
This is application of Integra, which is bovine tendon collagen with sharp cartilage. That's kind of how they make it and then also it's got bi-layers so on top of it is a silicone, which gives it some strength that you put staples in it. And so this is a lateral calcaneus after an infection. Use negative pressure over this in order to get granulation tissue over the bone and certainly to speed that. Generally, when I am putting -- when I am covering these tissue, I leave it on for as long as I can. I wanted to be on up to seven days and not change the negative pressure in between that time period. And so we can get to the point where we can apply a split thickness skin graft. Here, we grafted it. There is still a little bit of wound here but we're waiting for this by providing some debridement and good wound care. Until now, we have completely covered this bone and got this to close. Here is a similar case. A partial calcanectomy was performed here. You can see this void. Here is the calcaneus right here. But this really isn't ready for any type of graft yet. It's not bleeding very well. It doesn't look very clean. So we take this into the operating room. In this case, we are using hydro-surgical debridement, which is another form of advanced debridement to clean up the edges, get good bleeding and you could see the bone here and the partial calcanectomy down here. One of the reasons why I think these -- even though partial calcanectomies are complicated and have a lot of more proximal amputations required afterwards, they do very quickly get a lot of granulation tissue, and I think because the marrow is exposed to the rest of the wound and especially with negative pressure over it, you see a pretty robust and fast response to negative pressure with lot of granulation tissue in my experience.
Now, we have got something that's clean. It's in the operating room. It's ready to be covered this bone because we can't do anything yet. We can put a skin graft on this. This is still a little too far to approximate, so we want to get this bone to be covered first. So here we put a piece of amniotic tissue and we moisten it before we apply it and I just used my fingers and put it on and stick my finger in this deeper recess here. So it's covering the whole bone. Put negative pressure directly over it and I don't put an interface in between the negative pressure and these CTPs when I am trying to use granulation tissue. And the reason why is because the foam is designed to cause granulation tissue. Anytime you put an interface in there whether it's adaptic or silicone or anything you are interrupting the foam to wound interface and you might get some granulation tissue but you aren't going to get nearly as robust granulation tissue as you would if you have foam directly in contact with the wound. So when you put a split thickness skin graft on, we always put an interface over the split thickness skin graft because you don't want any granulation tissue poking through the interstices of the graft. You want to graft to epithelize. In this case, we aren't looking for epithelialization here. What we are looking for is granulation tissue so that it becomes level with the surrounding skin so that we can move to the next step and this is actually only after one week. And I didn't remove this. I took it back to the operating room and then removed it and here we have a wound that is in most cases it's leveled and granular. There is still a deeper recess here that has to be managed and so in this case, I moved to another tool that I like to used, which is a skin expansion device where you staple the clips along the side of the wound and you shoelace the wire through, twist this knob.
You have to suture this thing down to the skin. I Put a piece of foam under it usually to prevent any skin complications from the device itself from pressure. And you can get approximation here and this approximation depending on what part of the body you are dealing within the plantar foot generally takes about five days. The approximation will happen in the operating room most often but it's not redundant enough, free to put sutures in it for it to hold. So you wait three days anywhere else on the foot or leg for five days in the plantar surface of the foot. And then take back to the operating room and you can just use sutures. There is no tension on the incision and we have a final closure here. Split-thickness skin grafting. After we have used negative pressure to get granulation tissue over all the bone or maybe we have used a product of cellular tissue based product with negative pressure to get granulation tissue, now we have a leveled wound that's 100% granular. Even if it's not 100% granular, sometimes if it's 90% granular and it's kind of getting through this period, I would rather graft 90% granular wound and have a 10% failure than I would leave this and you know really get it down to much more manageable wound then leave a really large wound waiting for it to get 100% granular and then eventually just get an infection and you have to start all over again. So in this case, I had 100% granular wound, put a split thickness skin graft down here. These split thickness skin graft patients are also complicated and there is a lot of failures that can occur. In this case, we had a failure on the lateral and kind of plantar area where you can kind of see here where there is maceration probably all due to maceration.
It was very granular and so we had a complication there that led to a partial take or an incomplete take of this split thickness skin graft. Now, your options are to go back to the operating room and do another split thickness skin graft or treat it with conservatively in the clinic with multiple debridements and that type of thing. Or in this case, I used epidermal harvester to harvest an epidermal skin graft. Here we have a device that's placed on thigh. A suction device is placed over the top of it. It causes a bunch of little blisters and these blisters, which we call microdomes, you can see them in here, are forming under heat and suction. And it takes depending on what part of the body you are harvesting from, takes may be 20 minutes to 40 minutes to get these microdomes to form. Then once you have done that, in this case we use Tegaderm, you can use other things too like silicone. Raised this blue lever, closed it, a blade comes back and forth, chops off the tops of all these blisters. And so now what we have is a Tegaderm. So you have an adhesive with 120 or so little islands of epidermis. And so then you can take this and you can transplant it to the -- I never put it an occlusive dressing directly over wounds like that. So I poke a bunch of holes through this first and this is one of the benefits of using silicone now as a transfer medium instead of Tegaderm. But you can take this. Here is the donor site, barely see anything just from where the suction was and this usually heals in a day on the donor site. I have never seen the donor site complication in any of these that we have done.
And we just did review at Restorix. We have done 556 of these and we are looking to work with the company to help publish this but that will be the largest group of these that have been done but not a single donor site complication in any of those. And so here is that failed wound that I have mentioned. Now we apply it -- apply the Tegaderm here or now like I said we preferred silicone dressings to Tegaderm. So you are getting overlap but we are really focused on this area here and then here we have complete closure. I think the last part I want to mention is just adjunct to healing. One of the adjuncts that can be used is hyperbaric oxygen treatment and hyperbaric oxygen is 100% oxygen at increased atmospheric pressure, sometimes two times atmospheric pressure or three times atmospheric pressure. How it works is it saturates the hemoglobin that the oxygen -- it saturates the hemoglobin, which isn't the main mechanism of action. The main mechanism of the action is that the oxygen is all dissolved in the plasma of the blood and because it's under such great pressure, so it's just like when you open up a bottle of soda. You open a bottle of soda and all the carbonation comes out, the carbon dioxide. The same things happens in the plasma where you put it under pressure and you are forcing a 100% oxygen in and so it's getting in the plasma so that it can get around to where it needs to get. And effect lasts 8 to 10 hours after treatment. It improves the leukocyte function, tissue viability and wound healing. There are certain approved indications for this by CMS that we generally follow those in the diabetic foot and we are generally looking at patients that have Wagner grade 3 ulcer or higher. This is usually after an amputation that we usually qualify for something like this or a failed flap or failing graft.
I know that Dr. Fryeburg was presenting or he has a poster here talking about the use of topical oxygen and I find that really interesting and I certainly believe those results but I think the mechanism of action is probably totally different than using hyperbaric oxygen, which we use it on a very minority of our patients. But I used it and I will stop saying this now because I believe the result of the study but I used to tell people that if you don't believe that the oxygen is necessary to heal your wound comes from the inside out. You have to breathe it in and it goes through your blood stream and then gets to your wound. Try putting your foot under water for an hour and you pull your foot out and it's still alive but you put your head under water for an hour and you pull your head out and your foot is dead. Because the oxygen really does come from the inside but I think that the mechanism of action here is probably a lot different from topical. The data is better. So I will leave you with this last bit. I love to dive because I just talked about hyperbaric oxygen and when I was in Hawaii maybe three or four years ago, I found this master diver who advertised that he is going to get you up close and personal with the sea life. And at that time I thought that was a good idea. I wanted to do that and so we get under -- this is Karen Shum [phonetic], one of my former partners and fellow. And so we get under there and he finds this octopus inside of a reef and he gets it out and he starts like grabbing it. You know octopus doesn't have any bones, so he is holding as tight as he can and he is squeezing the legs like this and it's inking it you know. So now it's done inking and now it's trying to get away but it just puts his right in front and it just bounces of his hands several times.
Now it's tired and so the octopus is just like okay just have your calamari or whatever. And so he motions me to come over and he puts it on my arm because he wants to get a picture of the octopus on my arm. Well, I didn’t but maybe a second and then octopus is on my face and wrapped around my head. So I am thinking -- you know I didn't panic because that would be the bad thing to do. You know I am only 30 feet underwater but still that would not be very good. And so the problem was though that I lost situational awareness and I sank and I am on the reef now and I kneeled on a sea urchin. And then I got 16 spines in my leg and this is the lateral knee here. And then I get a foot drop because all of this seemed to have caused numbness and after I got back to LA, I did my own surgery and I had to use the punch biopsy and essentially punch out each of these because you can grab them with anything because they are made out of kind of calcium alginate that just fracture. So you just punch out over the top of everyone. So you get a punch biopsy that's larger than that and then sutured my own incisions. It's one of the negative effects of hyperbaric medicine, I guess, [indecipherable] [37:24] medicine would be something like this. So thank you very much.
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