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CME Surgery

Transmetatarsal Amputation

Nicholas Bevilacqua, DPM

Nicholas Bevilacqua, DPM discusses lower extremity amputation in diabetics, its impacts and indications. Dr Bevilacqua examines acute versus chronic wound criteria and appropriate timing and levels of surgery. Dr Bevilacqua describes in detail the methods he uses in surgery.

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Goals and Objectives
  1. Understand the economic, physical and emotional impact of lower extremity amputations
  2. List and understand indications for amputation and bone resection
  3. Study recommendations for surgical debridement with the goals of preserving healthy tissue and infection control
  4. Understand the application of recommended surgical methods for TMA
  5. List recommendations for follow-up care and support
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  • CPME (Credits: 0.75)

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    PRESENT eLearning Systems, LLC has approved this activity for a maximum of 0.75 continuing education contact hours.

    Release Date: 03/16/2018 Expiration Date: 12/31/2018

  • Author
  • Nicholas Bevilacqua, DPM

    North Jersey Orthopaedic Specialists
    Teaneck, NJ

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

    Dr. Friedberg: The transmetatarsal amputation has been called the diabetic’s amputation. For those of you who don’t know the history of this, it’s an old operation popularized in the late 40s at the Deaconess Hospital in Boston, still the largest series ever published. And this is a very important amputation because it saved countless thousands of diabetic legs.

    I couldn’t think of anybody better especially in Teaneck, New Jersey, to give this talk and that’s Dr. Nick Bevilacqua who’s done a really nice job for us. He’s a local Jersey boy. So I always like to use Dr. Bevilacqua to talk on diabetic subjects. He is with the North Jersey Orthopedic Group here. He trained in New York with Dr. Rogers and then went to Chicago for a diabetic foot limb salvage fellowship. And he’s a got a great deal of experience. So let’s welcome Dr. Nick Bevilacqua.

    Nick Bevilacqua: Thank you, Dr. Friedberg, and thanks to the remaining people that toughed it out. I know it’s been a long day. Hopefully, I’ll… right. We’ll go through this relatively quick for you just to get you out on time.

    So nothing to disclose for this lecture. So I know Dr. Friedberg gave a lecture early this morning discussing diabetic foot complications. And when you have a patient, either newly diagnosed with diabetes and even doctors for that matter, one of the most feared complications of diabetes is amputation. And traditionally, it’s been this higher level above and below knee amputations. And we know that a disproportionate share of adverse outcomes occur with these higher level amputations.

    So, Walters, he published this data, you know, going back 40 years now, just looking at the metabolic cost of walking with some of the higher level amputations. He just looked at above and below knee versus a Syme’s amputation at the time.

    And I think it’s, you know, fairly obvious that the higher level amputations, the major above and below knee require more energy to ambulate. And I think it’s also asking a lot for these patients, you know, when they just go through the trauma of losing a leg to have the motivation to get fitted for a prosthetic, to go to physical therapy and begin walking. So unfortunately, oftentimes these patients, you know, they’re not motivated and they never get back to ambulating.

    And, you know, we’ve heard all the frightening statistics on the five-year mortality rate. I think this has been popularized by Armstrong and his group when he sort of relates it to some of the more well-known cancers. And, you know, depending on the study, anywhere between 40% and 80% five-year mortality rate after these amputations.

    Jim Wrobel [phonetic], he’s done a nice job popularizing the high-low amputation ratio. And this is just, you know, a nice concept when you look at sort of the success of a wound care center images, you know, I’ll think about this in my own practice. It’s not so much the absolute number of amputations you perform, it’s the number of high-level amputations.

    So, you know, we’re going to talk about a transmetatarsal amputation, which is a very, you know, functional foot-sparing amputation. So obviously, we want the lower amputations, the foot-sparing amputations, to, you know, well outnumber the higher level amputations. And he actually just recently published a large retrospective review at one center sort of before and after the introduction of podiatry to the practice. And he found out by adding a podiatrist, he was able to significantly increase the number of foot-sparing amputations and significantly decrease the higher level amputations.

    So when you think about outcomes, again, knowing that five-year mortality rate with higher level amputations, how does this compare to some of the foot-sparing amputations? This was a study by Brown and colleagues 2012, you know, just a retrospective chart review. But they looked at a transtibial amputation, so the below knee and compare that to foot-sparing. And in their study, they just looked at TMAs, Chopart’s, partial and total calcanectomies. And when they looked at one, three, and five-year mortality rate, you could see that the transmetatarsal, you know, has significantly less five-year mortality rate.

    And they also looked at ability to ambulate afterwards and the transmetatarsal was significantly -- a significant difference was shown in the patient’s ability to ambulate after the foot-sparing amputation versus the higher level.

    So, you know, obviously, we want to perform the most functional distal amputation as possible, but, unfortunately there are many factors, you know, that we have to address that are going to determine at which level we’re able to amputate.

    [05:00]

    We’re going to think about infection and I’ll probably state repeatedly throughout the talk the importance of infection control with debridement and that’s initially going to dictate how much bone and soft tissue you have to remove.

    Vascular status, obviously important. It’s going to determine the predictability at the level at which we expect them to heal. Medical history and also function, which unfortunately I think is often overlooked. When I say function, I mean the functional result of the amputation that’s performed.

    So vascular status, just a quick slide, obviously these are sick patients. Usually, either, you know, they’re often inpatient, you perform a history and physical, if there’s any concern, noninvasive vascular studies. And I could tell you, for a majority, I’m getting a vascular consult, whether it’s the vascular surgeon or an interventionalist. I’ll usually be the one to order the noninvasive studies. So the results of the noninvasive studies coupled with the physical exam if there’s any concern whatsoever, I’ll get vascular involved. You know, we’ll talk about timing of the consult, you know, if they’re admitted or if they present to your office or the emergency with a limb threatening infections, sometimes you don’t have the luxury of, you know, waiting for a vascular consult. You may have to take them for that initial incision and drainage. Usually, the vascular specialist, they’re going to be the ones to order the angiogram or the MRI.

    So situations we want to avoid, so this was actually the case while I was a resident and it’s just always in the back of my mind and I try to include it in most of the talks. A nice elderly lady comes in with a simple infected ingrown toenail. Without a second thought, resident goes in, you know, blocks it, takes the nail out, you know, come back in two weeks. And when she comes back, you can see how she’s got that distal hallux necrosis there. So what happens, she ends up undergoing a 1st ray resection. And you could see followup two days later, she’s starting to get some necrosis at the skin edges there. One week, further necrosis and ultimately resulted in a below-knee amputation from an infected ingrown toenail. So this is something that obviously we want to avoid, but should never happen, especially in this case where an ingrown toenail, it’s not an emergency. You have to get vascular involved.

    Nutrition, I think, and this is medical optimization. It’s a team approach. Again, infectious is – I’m sorry, internal medicine involved with the goal basically to optimize these patients. Pinzur [phonetic] he looked at a large TMA study and found that patients that had serum albumin above 3.5, pre-albumin above 16, total lymphocyte count above 1,500, a higher predictability of healing.

    And then lastly function. We have to think about the end results. So we want to obviously control infection. We want these patients to heal but we want them to stay healed. And in residency, I could I’m surely you can vouch for it, we always sort of sometimes bang our head against the walls. When these patients would come in, they had a 1st and 2nd ray resection as you could see right here and so they are getting infection on the 3rd toe. And then what's the procedure is just a selective 3rd toe amputation, leaving the 4th and 5th and, you know this patient is going to come back in a couple of weeks or a couple of months with an infection underneath the 4th metatarsophalangeal joint or 4th toe. And this – I’m not sure how you sort of classify this type of amputation here but ulceration at the base of the 5th metatarsal. And instead of performing a more definitive, well-balanced transmetatarsal amputation, they just went and resected the entire 5th metatarsal. So again, not very functionally sound.

    So when we think about infection, 1st and foremost infection is going to determine the amount of soft tissue with debride. And also emergency versus non-emergency signs or clinical scenarios where we would have to take these patients straight to the operating room. And, of course, they always seem to come in Friday afternoon 3:00 and severe infection, ischemic limb, any sort of abscess. We worked with George Andros in Los Angeles for a short time and he would always have that saying never let the sun set on pus. And the point is these patients are sick. They’re limb threatening and often times, you have to really educate even the internal medicine doctors regarding the urgency in that initial surgical procedure because obviously they’re septic and sometimes they wanted to delay surgery.

    So the goal is to remove all infected and necrotic bone and soft tissues. So if you’ve ever heard Chris Attinger speak, he’s a plastic surgeon in Georgetown –

    [0:10:00]

    – you know, sort of simplifying it. If you cut it and it doesn’t bleed, it doesn’t belong there. Cut it out. Sometimes you feel like a deli slice or sort of slice by slice, layer by layer, do not stop until you’re getting healthy viable tissue. And sometimes, you’re faced with the decision in the operating room where you’re thinking about the end result or the thoughts of the reconstruction. Never let that influence that initial debridement.

    So you don’t want to recklessly remove healthy tissue. You’re going to leave anything viable in there but never limit the amount of debridement because this is by far the most important step in that initial surgery. These infected cases, they’re packed open. If I’m confident I got the infected tissue out, I’ll put a wound VAC, otherwise they’re just packed. Sometimes, it results in a partial foot amputation at that initial surgery, sometimes it’s just an open wound. And I tell patients that it’s a debridement, we’re removing all the infected bone and soft tissue and they result in partial foot amputation. So our team will determine if it’s going to be a ray resection, if it’s going to be a transmetatarsal amputation so you have to discuss that obviously with the patient.

    And once we control the infection, because again that’s our priority for that initial surgery is infection control, then we get our vascular colleagues involved. And if there’s any sort of lack of flow that’s the time not to re-vascularize for that more, you know, setting us up for a positive outcome for that second definitive procedure.

    Non-emergent cases, so this is a patient, non-functional amputation, not surprising that they ulcerated medial part of the foot. So they come in your office, at least if it's a Friday afternoon, you don’t have to rush to the operating room. These could be, you know, you have the luxury of time. They’re not emergent. I can still consider them urgent cases because we wanted to get these closed but that’s when I get vascular involved beforehand and that’s when I plan on a more definitive procedure of single stage.

    So when we’re in the operating room and we’re faced with this, we have to, again, debridement. We have to explore the sinus tracts. We have to eliminate undermining, explore tendon sheaths. I mean this was one where patient comes in, what looked like a pretty localized ulceration on the distal Achilles tracked all the way up. And again, sometimes it’s tough in the operating room when you get a little nervous, you have to just keep going until the – until you’re confident that you’ve gotten to normal tissue.

    So you just want to identify nonviable soft tissue, nonviable brown clotted veins, take them out, non-bleeding skin. This is just further nidus for infection so you have to remove it. Again, deli slice, layer-by-layer, you cut it, if it doesn’t bleed, take it out. Gray fat that liquefied fatty necrosis all comes out, soft stringy fascia. Sometimes, you get this Achilles tendon ulcerations, it’s difficult to debride it because you realize that you’re removing a significant amount of Achilles tendon, don’t worry about that. Just remove it until either you have a healthy tendon fibers or sometimes you have to resect the entire Achilles tendon. Once the infection is controlled, then you worry about function whether it be second stage, FHL transfer or cadaver tendons but that shouldn’t be your concern at that initial debridement.

    The same thing with bone, layer-by-layer until you’re getting healthy bone. They talk about the paprika signs, so you should be able to cut it and see that sort of pinpoint bleeding.

    So when we think about diabetic foot infections, we can sort of go down the list. Obviously, this one we’re going to focus on transmetatarsal amputation. I apologize. Trying to go faster guys, but the computer is slowing me down.

    So indications initially described as you heard Dr. Friedberg popularized in the 1940’s, initially for gangrene of the digits but we know any sort of severe 4th foot infection with an abscess, chronic osteomyelitis. I have here previous 1st ray resection or hallux amp with a sort of result in ulceration underneath the 2nd or 3rd metatarsal heads which is very common if we understand the natural history of a great toe amputation. And sometimes this is tough to talk to patients and educate them in terms of the long-term results as opposed to doing that piecemeal surgery where we’re just removing a 2nd toe and then a 3rd toe and then a 4th toe. We go right to the definitive most functional transmetatarsal amputation. They come in all shapes and sizes, whether it’s ischemic, infection with ischemia, abscess.

    [0:15:01]

    This was one of the more recent ones. It was a diabetic with a congenital foot deformity that had this sort of pre-ulcerative lesions underneath 1 and 5 and did well with a transmetatarsal amputation.

    So now in the operating room, fish-mouth incision, try to maintain a long plantar flap. Incision is going to be placed proximal to many affected tissue, whether it’s gangrenous or infected. Think about the final suture line lying dorsally. So we want to get that nice long plantar flap, so when you close it, there’s a nice dorsal incision. When you make the incision with a scalpel, it’s full thickness. Especially when you’re on the metatarsals, you want to limit tissue handling on the edges. You want to minimize undermining.

    So just some general principles, incisions, medial and laterally should be at the junction of the thick and thin skin. They should be down to bone limit undermining and excessive handling of the tissue. You’re going to remove all infected and necrotic tissues. Tendons are going to be transected under tension.

    And this was a nice little pearls published in JFAS in 2011 just highlighting the importance of preserving healthy tissue. So we’re going to remove anything that’s infected. But if we can preserve some of the viable vascularity in between the metatarsals just to maintain some vascularity at the plantar flap, that’s important. So we don’t want to get overly aggressive and just start removing everything.

    So when we think about bone resection, we have sagittal saws, gigli saw. I tend to use the sagittal saw a little bit more often only because I can sort of plane my cuts, I'll angle them dorsal, distal, plantar, proximal on all the metatarsals just to prevent any bony prominence as plantarly. Media and laterally, you know, medially I resect more medial, laterally more lateral just to eliminate any possible bony prominences that would’ve, you know, affect our long-term outcome.

    Anyone who maintain that metatarsal parabola maintaining, you know, at least 20% of the metatarsal length ideally. And, again, you want to avoid having, you know, a situation like this where you have this, you know, bony spikes that will probably increase the plantar pressures and result in skin breakdown.

    So again, meticulous handling of the skin hemostasis. So, you know, no tourniquet for these procedures. Just out of habit, I usually apply a tourniquet, never inflate it because you want just want to do a good job, sort of assessing the viability of the tissue, remove all exposed tendons under traction and you want a debulk, you know, not excessively. But if you’re having a hard time bringing that plantar flap up, you can debulk some of that soft tissue.

    You know, if it’s a stage procedure, I'll still do the debridement first, pulse lavage, and then that’s when I'll take my deep tissue culture. So usually, I'll take off my outer layer of gloves and I'll use all clean unused instrumentation to try to get those clean margins that, you know, we heard in the previous lecture to help direct antibiotic treatment moving forward.

    So closure, I tried to avoid bearing a lot of deep sutures. I'll consider a drain for any of these cases, you know, if you’re closing that flap and you feel like there’s dead space and there’s, you know, blood pooling and you’re worried about a hematoma, absolutely put on a drain. I mean, these patients are going to be admitted to the hospital. Put it in a drain if there’s any, you know, any sort of thought about it. And then just 24 to 48 hours later, I'll just pull it on bed side. I usually use Prolene and the goal is to obviously close with minimal tension on the skin edges.

    Nowadays, we have a lot of these disposable negative pressure devices. I don’t think it works well, so I tend to use these devices on my sort of higher risk incisions, so you can consider using topical negative pressure wound therapy or the incision. And you can see just the traditional device versus one of the newer disposable ones. If you are unable to get the skin edges to coapt, consider negative pressure. When we think about negative pressure in partial foot amputations, this is sort of its prime indication. You know, just resist the urge to really close it under excessive tension because that’s going to result obviously in a wound breakdown.

    So here was a case, you know, we’re more confident that we resected all the infected tissue. We maintained as much of a plantar flap as possible, but we just weren’t able to get those skin edges together, so negative pressure wound therapy.

    [0:20:01]

    And you can see here, this was just combined with one of those biologic dressings and the patient did well.

    So staged procedure, this is Lee [phonetic] giving me the thumbs up that we’re ready to -- that his confident we got all the infected tissue out. So, again, if it’s a staged procedure, you have the option of antibiotic beads, retention sutures, you know, packing it open, they’re going to get readmitted, you’re going to follow them while they’re in the hospital and then negative pressure.

    So negative pressure, after partial foot amputations, really proven effectiveness from this randomized controlled trial from Armstrong and Lavery published 2005. And they had higher proportion of healed wounds in the patients that had negative pressure, faster time to wound closure and a potential trend towards reduced risk for secondary amputations.

    Tending considerations, obviously we want to perform the most sort of well-balanced functional amputation. So you have to redress that Achilles tendon. You know, there was most likely probably an equinus deformity present beforehand. And if not, you’re resecting all those extensor tendons after the procedure, so you’re going to get that unopposed pull of the Achilles tendon. So, usually, always address the equinus.

    If it’s going to be a staged procedure, I’ll do it, you know, second. When it’s a cleaner environment, if it’s a single stage, I’ll just do it right at the same time. If you think about tendo-Achilles lengthening, essentially you’re weakening the Achilles tendon, you know, and you’re also getting that temporary increase in ankle range of motion.

    Just be careful that, you know, you’re not transecting it because they can rupture. And in some cases, if they develop a calcaneal gait, then you have to worry about one of those difficult-to-heal heel ulcerations.

    There’s been some other – you want to preserve basically tibialis anterior, the peroneus brevis tendons, you can attach peroneus longus to brevis. You could – that’s been described attaching the extensor tendons to the flexor tendons distally. And even Ruckus [phonetic], he talked about in more of dysvascular foot where he had to do tendon re-balancing, but did not want to further insult the foot with incisions. He actually used intramedullary screw fixation.

    So just a quick little video here. So this is just kind of a quick video putting it all together. So, tendo-Achilles lengthening usually a triple hemisections so each one is – you’re transecting about 50% of the tendon. And then after you do that third incision, it’s sort of a gentle dorsiflexion and you can usually feel a slide as opposed to having the foot hit the tibia.

    Incision again, this is right at the metatarsal levels, I’ll just go right down to bone and you could see I don’t even a pickup in my hand here. I just want to really preserve the skin that just there. Making a plantar flap and then you’ll see carefully just exposing the metatarsals with sort of limited dissection with periosteal elevator and then just using a sagittal saw to cut the metatarsals. Again you want to bevel these dorsal, distal, plantar, proximal and then I’ll take a little bit more bone off medial for the 1st and more laterally for the 5th.

    So after just careful dissection again, try to maintain as much viable tissue in between the metatarsals as possible. And you can see here just removing that infected forefoot segment. We’re going to use this, this is just a hydroscalpel you want to further debride, resect the tendons, pulse lavage and then, you know, that’s when we would take cultures and you can see here how the flap would close.

    Post-op management initially oftentimes, I’ll just put them in a very bulky modified sort of Jones compression type dressing with a posterior splint and then I put a cam walker here. But oftentimes initially until that wound is healed, these patients are not putting the foot on the ground until the incision is healed. Long-term either depending on if there’s any sort of a muscle tendon imbalance, I mean ideally you just get him in an extra depth orthopedic shoe with a forefoot filler. Sometimes you may have to, if it’s a little bit more proximal amputation, you may get this customized AFO with a forefoot filler.

    Complications. So this was a study by Mueller [phonetic].

    [25:00]

    You know, a large study of 120 TMAs performed on 107 patients. And just looking at the follow up, so 27% develop skin breakdown and what was interesting is that the majority of complications or skin breakdown cases occurred within the first three months. And then if you look at those who requiring a subsequent higher level amputation, again they are occurred within the first year. So I think it’s important initially to really protect these patients. So I put them in that splint. They are non-weight bearing, oftentimes at least three weeks, most likely four weeks and then you can sort of transition them to partial weight bearing to weight bearing in a cam boot until you get them fitted for an orthotic with a filler or an AFO.

    When applied, the most common complications are equinovarus deformity and that’s where ultimately we address this during the procedure. Tendo-Achilles lengthening, sometimes even tibialis anterior you could do a split tendon transfer where you take half of it, insert it laterally just to help prevent that varus deformity.

    So, just to finish up with a couple of cases here. And again, never let the thoughts of the final outcome, never let the reconstructive component, limit debridement. So this was the patient where infected and necrotic forefoot, transmetatarsal amputation, but we have to remove a significant amount of tissue dorsally which initially when you were in the operating room, you’re hesitant to do that because now you are not going to get a good second surgery to primarily close this.

    You can still tack that flap. Sometimes you can even as recently described in tips, quicks and pearls, I think in JFAS where they actually make drill holes in the metatarsal and deep sutures in that flap they’ll put it though those drill holes just to keep that planar flap in place and we did sort of something similar to time there.

    Negative pressure, really the goal was just increase and promote granulation tissue. We got a good healthy granular base and we then we are able to apply a split-thickness skin graft. Ultimately went onto closure and you could see good, viable plantar foot well balanced so we expect a good outcome in the long run.

    Similar case here, just put these up, just to kind of show you the importance of, you have to remove anything that is infected and non-viable.

    So I’ll just close, one more little case here, did this, you know, this was the case Lee and I did when we are the good old days and I were here. And you could see here, again infection tracking up the extensor tendons. And you have to debride it and you have to sort of decompress that whole area. And we were left with a massive defect but this is really where the beauty of negative pressure comes in. I think of it as a wound simplification device, I put the VAC on, I get to go home sort of, you know, realize that the wound is in a good, optimal wound environment and I can think about stage two. And in this case we used one of these skin tensiometer devices. We control the infection. We are getting the wound closure more proximally and then when we took the patient back to close that incision, we did a more definitive transmetatarsal amputation just to hopefully give them the best long-term outcome.

    Thank you.

    TAPE ENDS - [28:23]