Nicholas J Bevilacqua, DPM discusses the treatment options for diabetic foot infection. Dr Bevilacqua also identifies common presentations and reviews treatment options including amputation for severe foot infections.
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Nicholas Bevilacqua, DPM
North Jersey Orthopaedic Specialists
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TAPE STARTS – [00:00]
Male Speaker: Another important topic is going to be [Nick Bevelock] [00:03] with discussion on surgical management of diabetic foot infections. And again, diabetic foot infections are extremely important for you to properly not just diagnose, but also manage because they are the things that are going to get patients into trouble and will most directly lead to limb loss.
So Dr. Bevelock was going to be talking about this, and we’re also moving up his second talk on Charcot foot essential concepts which will follow immediately. So let’s listen to Dr. Bevelock and see what he has to say on surgical management on foot infections. Okay, thank you, Nick.
Nick Bevelock: Thank you and good morning everybody. So I do apologize if there is some overlap with my talk last night on the transmetatarsal amputation, but both of them sort of detail the surgical management of infections. Nothing to disclose for this lecture.
Pathophysiology, obviously, diabetic foot ulcers come in complication with someone with diabetes and neuropathy. About 25% of patients with diabetes will grow and develop an ulcer in their lifetime. And then infection is one of the most common complications that we see and it’s usually the precipitating event to lead to hospitalization and amputation.
So you have to become very familiar with clinical signs and symptoms of infection. Local signs, obviously, if there’s purulent drainage when you express it, you can see from that video up top there, if there is at least 0.5 centimeters of surrounding erythema, localized inflammation and Dr. Rogers in his previous talk, talked about, you know, signs and symptoms with red-hot swelling foot.
And then also systemic signs to understand these patients. Sometimes, the sickly diabetic patients are not going to mount that, you know, typical leukocytosis. And sometimes it will actually remain afebrile, so you really have to look at the, you know, the overall patient, but look at the localized symptoms in the foot.
Some secondary signs some that you can be cognizant of, presence of necrosis, febrile or discolored soft tissue, granulation tissue, non-purulent secretions, malodor and, obviously, you have a wound where you’re offloading to have good perfusion and it’s just not healing.
When we think about imaging, first and foremost, radiographs, simple test. You just going to look for any signs either in subtle periosteal reactions and you break in the cortex, you know, look for foreign bodies, any subcutaneous gas. And also want to look and differentiate that from Charcot foot. And obviously, if you see gas on the x-ray, correlating with a severe clinical signs, that’s a surgical emergency.
Osteomyelitis is going to complicate about 20% of the mild to moderate infections, more common in the severe infections upwards of about 60%. Clinically these are wounds that are deeper probing to bone. Patient if they have history of osteomyelitis, obviously, they can be more at risk. We think of these patients sort of going into revision, oftentimes as opposed to getting a cure and then also if they have history of carnal ulcerations, you have to be just be aware, have a heightened index of suspicion for underlying bone infection.
So when we think advanced modalities, I think, obviously, x-ray, first and foremost, and then MRI, very useful. Oftentimes not necessarily used to diagnose infection, but used to determine the extent of infection. Sometimes, if I’m unsure if there’s a deeper, hidden abscess, I’ll do an MRI just to uncover that. But really just looking for the extent of infections, sometime using this sort of a blueprint for surgery just you can sort of see what you’re up against.
And there’s even some studies looking at secondary factors differentiating osteomyelitis from Charcot. But, I know, there’s a speak later this – talk later this afternoon, basically differentiating Charcot from osteo. So I’m going to sort of skip over that.
Lab studies, obviously, these patients, if they have a severe infection, they get admitted to the hospital, you can get infectious disease on board, you can get interim medicine onboard. Usually admin orders blood cultures, CBC with differentiation, obviously, as I mentioned before, may or may not have increased white blood count. You can get basic metabolic panel and then usually I’ll get a sed rate and a CRP.
So ideas there and we ran over this a little yesterday, classification, you know, just a simple find, it’s either uninfected, mild, moderate, severe and you can see some of the signs and symptoms that we’ll see with each class.
Mild infections, generally, skin, underlying soft tissue, less than 2 centimeters and surrounding erythema. No systemic signs of infections. Oftentimes you see these patients in the office, you treat them as the out-patient, pure antibiotics.
Moderate infections, these are the patients that have deeper infections. They’ll have purulent drainage and oftentimes, you know, these patients require some sort of – most of the time admission. And then severe infections are those limb-threatening infections that are oftentimes surgical emergencies.
In terms of bacteria, mild infections primarily staph and strep, severe infection is really rare. You can get that polymicrobial broad spectrum antibiotics. And that’s when you’re concentrating on that MRSA, de-escalation therapy. It’s a validated classification system, meaning, as the infection becomes more severe or the more severe infections often result in, you know, greater chance of hospitalization and amputation.
So when we think about the team, obviously, this is, you know, patient is front and center. But I just oftentimes can act as the gate keeper, so oftentimes, you’re getting called in the emergency department or to come in, in your office, and you know, I’ll call up my infectious disease doctor and it’s always good to have a good personal relationship with them because, you know, you’re going to have a role in terms of determining the best course of antibiotics.
You know the patient’s history best. You get – you talk to the radiologist when you send them for an MRI, just give them for phone call. Tell them, you know, tell them what you’re looking for. Oftentimes they’re just getting this patient history of, you know, infection and sometimes, you know, they’re having hard time differentiating osteo versus Charcot so it’s always good to have a dialogue with different specialties. You need to get vascular surgery involved. So just – it should be a multi-disciplinary team approach.
In terms of antibiotic coverage, again, mild infections, you’re really looking at gram positive coverage. If there is risk factors for MRSA, you got to deescalate, and if not, usually, you just go with a simple penicillin derivative allergies, consider clinda.
And these patients, you know, deep tissue cultures are taken but this is sort of prophylactic and then any antibiotic course is going to be adjusted based on the culture results. Moderate and severe infections MRSA, MRSA de-escalation.
I think one of the most powerful antibiotics is the number 15 scalpel blade. So if these patients have a deep abscess, this is a surgical emergency. So, you know, it doesn’t matter if you give them the strongest most broad spectrum antibiotic. These patients need to be taken to the operating room, debrided, remove all – uncover any abscesses and remove all non-viable tissue.
So I talked about this yesterday. Infection is ultimately going to determine the timing. If it’s, you know, the moderate to severe infections, those are surgical emergencies and they are emergencies. So these patients should be brought to the hospital for that initial incision and drainage.
And sometimes, it can actually result in a partial for an amputation at that initial surgery. So again, the goal is to remove all non-viable tissue or infected bone and soft tissue, and talk to the patients.
You know, I think about this in different phases of treatment and I explain it to the patient. This first phase, first and foremost, we are in infection control. And by that, I mean, it’s going to involve possibly multiple trips to the OR, it may result in partial foot amputation. It’s hard to determine the level at that point.
And when you’re in the operating room, you do these cases, often times, there is no tourniquet, just to assess the viability of the tissue, you’re sort of, I mentioned yesterday, it’s like a deli slicer. You’re going layer by layer removing the infected tissue, and stopping only when you get to the healthy viable tissue.
And you cannot let sort of thoughts of reconstruction and the final result impact or limit your debridement. So you don’t want to remove more than you have to, but certainly, you don’t want to leave any infected or necrotic tissue.
In these emergency cases, often times, I’ll take them to the OR, and then I get vascular involved afterwards, if there’s issues with profusion.
So you want to uncover any sinus tracks.
You want to eliminate undermining oftentimes tendon infection, bacteria follow the path of least resistance. Typically we see this with this Achilles tendon, so it’s again you have to discuss this with the patient. They’re coming in, they’re neuropathic, they don’t even have pain, and they’re looking and they’re saying “Oh, I just have this small little wound in the back covering my tendon,” and they come out with a massive wound, but yeah, you just have to tell then the importance.
Signs of non-viable tissue in bone, clotted veins, nonbleeding skin, again you’re just going to remove it until you get nice healthy bleeding skin, great – soft stringy fascia, different – doesn’t matter the debridement tool whether it’s aversa, the hydro scalpel, scalpel blade, it’s just – most important thing is just eliminating the infected nonviable tissue.
So which level do we amputate? Because oftentimes these initial debridements may result in foot-sparing amputations or ideally foot-sparing, so we want the lower level and avoid the higher level. So infection, we talked about vascular status is going to determine the predictability or the level at which they can heal. Medical history and medical optimization, and ultimately we want to perform the most distal functional amputation.
So when we think about different foot-sparing amputations, I’ll go over some of these just to give examples where working from distal to proximal. We have just digits, hallux, first ray, transmetatarsal, Lisfranc, Chopart, Syme, and either a partial or a total calcanectomy. Just some generalized guidelines we want to – of course, we’re removing all the nonviable bone and soft tissue.
Skin incisions, you want to limit undermining – you want to limit excessive soft tissue handling. So these incisions are mostly right down to bone. And afterwards, you’re going to inspect, you’re going to irrigate, and that’s oftentimes when I’ll take deep tissue cultures. So I’ll do these deep tissue cultures after the initial debridement. I’ll remove – so I’ll usually use the pulsed lavage, remove my outer layer of gloves, use clean unused instrumentation, and then I usually get deep tissue and bone. Hopefully, at that point, a clean margin so I have the nurses label everything and it’s going to pathology, it’s going for cultures and sensitivities.
So when you think about digital amputation, the most common amputation in the foot, incision sometimes is sort of dictated by the ulceration in the viable skin. Ideally, if I have a good plantar flap, I can bring up just to maintain that tough durable skin. Sometimes, you can just make it linear. We have medial and lateral flaps. And for lesser toes, they do well, preserving the medial and lateral circulation and really, minimal weight bearing forces on these stumps.
If possible, if there’s a distal osteomyelitis or infection, I try to preserve the base of the proximal phalanx. And that helps just to act as a buttress to prevent sort of drifting of the adjacent toes. So oftentimes these patients just go in at extra depth orthopedic or diabetic shoe with no formal prosthetic.
When we think about a hallux amputation, if it’s distal, very distally you can just do a little distal exam. If it involves the distal phalanx, usually I’ll just go one joint proximal. Same concept, I try to preserve a plantar flap if possible. Otherwise, you sort of work – we had a good discussion yesterday when Dr. Freiberg put up that case with the TMA. Sometimes, you’re limited by that initial debridement and you have to work with the tissue you have.
So again, if possible, I try to leave the base of the proximal phalanx. Again, just to act as that buttress, prevents that medial drift of the lesser toes that we often see with first ray resections as you can see from that picture there.
So when you think about a first ray – so now we’re just – infection or necrosis is moving more proximal. So now it involves the first metatarsophalangeal joints, so we’ll do a partial first metatarsal resection. Again, I try to use a raquet-type incision, bring that plantar skin dorsally so I have that incision line on the dorsal part of the foot, and I try to angle the cut, dorsal-distal. Take a little bit more medial just to prevent any prominences.
Again, sometimes these are stage procedure so you’ll do that initial ray resection with an aggressive debridement.
And at that time, you have to remove all the infected tissue and you’re left with this defect and there’s a thought in the back of your mind questioning how you’re going to close this at the second stage. Don’t let that deter you from aggressively debriding the infected tissue. But on the other hand, now, we’ll have to use some of our tools and tricks to obtain wound closure. And in this case, that’s really where negative pressure therapy comes in. I think of it sort of as a wound simplification device. You could see that initial picture post-op, sort of irregular depth. Negative pressure will kind of promote and enhance that granulation tissue, more evenly distribute. And then at that point, we can consider either split thickness skin graft, bioengineered tissue grafts.
Utility of negative pressure for partial foot amputations, this was a study published by Armstrong and Lavery last 2005, showing the sort of efficacy and the advantages, really, of using negative pressure in this situation. Higher proportion of healed wounds, faster time to wound closure, more rapid and robust granulation tissue, and a potential trend towards reduced second amputations.
So this was an initial study by Murdock in 1997. He followed the natural history of a first ray resection, but in this series it was really any sort of hallux amputation, and also with the first ray. And I was actually surprised to see the high percentage. You could see 60% of these patients went on to develop or went on to requiring a second amputation. 11% required transmetatarsal, 21% went on to a third and 7% to a fourth. And the authors concluded that a large proportion of their patients receiving a greater or first ray resection received a higher level amp the following year.
And this is common. We do that first ray resection, we get that sort of result in hammer toe of the second with the contracture and then you get an ulcerate underneath the second metatarsal head.
Luke Adelapola, he looked at his series of 89 patients that underwent a first ray resection, and he had a lot better results. So he had only 15 patients which equated to about 17% - patients ulcerated after that initial surgery. And he attributed that low re-ulceration rate to their really aggressive follow-up program. So he had these patients basically fitted for custom insert and they used a rocker bottom shoe. So his feeling was that these are durable amputations.
Just a quick case showing this patient had a previous hallux disarticulation bilaterally. And unfortunately for him, he also recurrence with osteomyelitis on both, taken for that initial debridement. Wounds were left open so I’ll either pack them or back them. And a once you follow up your clean margins, everything looks clean with the cultures clinically, it’s progressing well. These patients go on for a second delayed closure of the wound. Negative pressure in this case really helps maintain that optimal wound environment while we’re either waiting for cultures, just monitoring the infection before we want to close it. And it helps prevent sort of that contracture of the soft tissue that sometimes make that secondary procedure more difficult. These patients, good custom support, rocker bottom sole of the shoe as the previous study demonstrated is beneficial.
So when we have the essential ray resections, we talked a little about this last night, these are difficult scenarios. If they’re isolated to the second or third toe, sometimes if you do a ray resection, it can result in a mechanically unsound foot that can basically create a residual wound that’s very difficult to heal. Or if it does heal, we’re just concerned that the result in foot is not functional and it’s going to be at risk for skin breakdown.
So this is a case just highlighting a sort of surgical technique Lee Rogers and I wrote up. And it’s basically central ray resection with fore foot now. So same concept, you’re doing that initial debridement, ray resection. And using this mini external fixator, applied dorsally, usually two pins in the first metatarsal, two pins in the fifth. And we’re manually compressing the fore foot and the external fixator is just holding that reduction in place. And that allows us to primarily close the incision under minimal tension.
And afterwards, these patients heal well, so more likely for that incision to heal because there’s less tension on it.
And oftentimes, patients are happy because if you just look at his foot, you almost have to just sit there and count the toes. It’s not a noticeable toe reputation.
So if we have a wound laterally on that fifth metatarsal, similar to the first ray, we could do a fifth ray resection. Same concept, raquet-type incision, try to bring that dorsal skin up. I show this case just because, again, you never want to limit debridement. Don’t worry about the closure at that initial visit. Removal of unhealthy tissue, negative pressure, get a granular base, and now we have options.
So again, I don’t want to overstate or I don’t undervalue the importance of having non-invasive vascular studies, having vascular involved. So once we get these patients and that initial infections under control, if there’s any concern, that’s when they’re getting referred, possible open, just a bypass or revascularization.
With the end vascular of procedure, transmetatarsal amputation – I talked about that yesterday. So I’m going to skip over these indications. Basically, gangrene infection to the fore foot, we went over this last night in a bit more detail.
So I guess for those that skipped the lecture last night, I’ll show you the video. So this is just to summarize it, transmetatarsal amputation. Oftentimes, we do this in conjunction with a tendo Achilles lengthening. Dr. Rogers spoke nicely about that, triple hemisection, percutaneous three incisional approach. These patients are supine so usually we just elevate it, and 50%, 1 centimeter apart. Usually I just do at least about a thumb’s width apart.
And then I said, a gentle, slow, dorsal reflection. Skin incision is going to be proximal to infected and necrotic bone soft tissue. Again, you want to minimize excessive tissue handling. This incision, especially at the layer of the metatarsal, is down to bone. I’ll try to preserve as much healthy uninfected tissue in between the metatarsals just to preserve vascularity to the plantar flpa.
And you can see here just exposing the metatarsal shafts. I usually use a sagittal saw. And another option, as Dr Friedberg likes to say, jiggly saw– jiggly. He makes fun of me when I say the giggly. So we we resect these metatarsals. I use the sagittal so just because I like to plane, you know, dorsal distal to plantar proximal just to prevent any bony prominences. I mean, you can certainly use whichever technique is most comfortable for you. Just debulken the flap. Again, you don’t want to an excessively debulk this because you don’t want to devascularize it, but just removing tendons under tension.
And you can see here that we're able to get a nice plantar flap. We talked about this yesterday in the case study if –you know, sometimes you actually have an excess skin where you are concerned that you are going to get maybe a hematoma, and that’s when you would put in the drain.
So post-op management for transmit to dorsal amputations, I put them in a bulky compressive dressing, post-used but not weight bearing. And I tell patients, you know, the foot doesn't touch the ground until I take the sutures out. And then once we do that, usually, it's in one of CAM boots and that will progress them to either just an extra depth orthopedic type shoe, often times with one of those plasters out inserted with a forefoot filler if I resect more. So, ideally, want to leave at least 20% of the metatarsals intact. But, you know, as I go more and more proximal, either a really proximal TMA or a less frank, I’ll put them in a custom AFO.
Complications, again, I showed this yesterday. But just to kind of briefly summarize, you know, real – so ratio rate, these patients are going to breakdown and, you know, this study by Mueller, looking at a large case here. He's found that most of the complications actually occurred early on and 28% required higher level amputations. So I think it’s important to protect the newly amputated foot as the patient sort of gets adjusted to ambulating.
One of the most common complications, varus and equinus deformity. So equinus, ideally, we're addressing that initially with a tendon or Achilles lengthening. Varus, if there’s, you know, any sort of varus deformity, you know, initially, when you're performing it, you could do split tibialis anterior tendon transfer, sometimes we will split that, take half of it and insert it laterally.
Sometimes it's a later sort of deformity that develops overtime and you can always take them back to address that.
This was just a retrospective case study comparing the outcomes of transmetatarsal amputations to below knee amputations. And, you know, really, the important point of this slide is if you looking at 1, 3 and 5, your mortality rates, transmetatarsal amputation is significantly lower compared to our below knee amputation. And post-op ambulatory status, they used to scoring scales zero to six, six being basically community ambulators can walk unassisted in a decent of stairs, zero being patients bedridden.
You can see transmetatarsal amputation 4.3 versus below knee amputation is at 2.8. And I think this is – I mentioned yesterday patients have a below knee amputation, I think it's asking a lot for these patients to have the motivation to get the prosthetic, be fitted for the prosthetic, go to therapy and walking. So I think the unfortunate reality is most of these patients probably end up being wheelchair bound. So we're obviously performing limb salvage.
So now, again, transmetatarsal, very functional, very durable amputation, but if the infection or the necrosis is more proximal, sometimes we're obligated to remove the metatarsals as a whole. And this is really where tending considerations become more important because now we are losing tibialis anterior, we are losing peroneus brevis. So oftentimes, I'll try to salvage tibialis anterior. Sometimes I drill hole through the talus and/or I'll tact it more proximally. And this really becomes important which is Chopart's. For these, I definitely– I try to do my best to tact it. So usually do a drill hole for the talus and bring that tibialis anterior through that and then these are always getting tendon or Achilles lengthenings
So Chopart's is a good amputation for failed TMAs and even for these really severe mid charcots that have abscess with infection, where you're basically just leaving the talus and calcaneus, try to preserve a viable flap, I'll often put in a drain. So I worked with Vince Mandrake, and he would always say, no drain, no brain. So in the OR, if I'm contemplating using a drain, obviously, I'll use it. Initially, these patients, just like that TMA bulky comprehensive dressing where the posteriors point, non-weight bearing until the incision is healed.
And then long-term, these patients are all fitted for that custom molded AFO, as you could see in this patient here. And he's have sort of that built-in forefoot filler. So that same study by Brown, where I just showed you comparing transmetatarsal amputations to below knee amputations. They also looked at Chopart amputations. And mortality rate was interesting. It wasn’t significantly less compared to the below knee. But, really, what was a lot better was that post-op ambulatory status. So you are maintaining patient independent, they don't have to wear a prosthetic. They still have a viable stump to walk on.
Just finishing up here, kind of moving proximal Syme's amputation, pretty much disarticulating the foot at the level of the ankle, requirement, good, healthy, viable heal pad. And if you think back the original work, Waters, 1976, so going back 40 years, really, where he compared the energy requirements ambulating in major versus lower level amputations, He looked at above and below knee amputations and compared that with the Syme's level amputation.
So, really, what we're doing is maintaining this patient's independence. And I always think about it, you know, these patients are going to be household ambulators. So we don't expect them to go outside and, you know, walk, food, shopping. They're probably going to be in a wheelchair when they go shopping. But at least in the house, we maintain their independence after they use the bathroom in the middle of the night, they don't have to search for a prosthetic. They have a functional limb to walk on. So I do think there's certainly an indication for it.
Partial calacanectomy, so this is a difficult scenario when we have these plantar heel ulcerations complicated by osteomyelitis. And the option is really become – sorry about this. This is just showing incisional placement.
Options are partial calcanectomy versus, sometimes, you have to do a total calcanectomy. A recent systemic review looked at 16 studies. And basically, again, they found that 85% maintained or improve their ambulatory status. And partial calcanectomy is a viable option for limb salvage. And again, patient expectations, so if it's in elderly patient, household ambulatory I think is a great procedure, younger patient, you know, they may be better off below knee amputation. So I think it a lot of depends on sort of the individual. And same study, comparing the proximal versus distal amputations, the below knee amputation versus partial calcanectomy. If you look 1, 3 and 5, the mortality rate is similar, no significant difference. But, again, partial calcanectomy, you look at that post-op ambulatory status, 4.3, significantly higher than a below knee amputation. And even the total calcanectomy was higher as well.
So just to finish off with osteomyelitis, so we talked about, you know, ostemyelitis distally, in the forefoot. Ultimately, you could debate antibiotics alone, antibiotics with surgery. You know, what about if it's distal tibia or ankle joint? I think, ideally, optimal treatment is a combination of both antibiotics and surgery. Surgery, being we want to remove all infected tissue, infected bone. Often, stage procedure, I'll put either an antibiotics space or antibiotics beads. And usually, infectious disease is supplementing this with an IV PICC line 6 to 8 weeks and then patient comes back for a more definitive procedure. And usually, I'll use sed rate and ESR.
So 52 seconds – I'm actually 56 over. So I'll just go quickly through this case.
A 57-year old male died, begins with neuropathy, charcot with an unstable mid foot comes into the office, low grade fever. You can white count not necessarily elevated, 9.2, because of a very high sed rate, you know, just recall some of the paperwork in the past or records in the past, if it's above 70, a higher chance of osteomyelitis. So patient's admitted, severe limb threatening infection complicated by charcot, so this is where it becomes, differentiating charcot from osteo, went to the operating room twice and waiting soft tissue.
And oftentimes, and I'll ask myself if the patient is not improving, we may consider an MRI to further evaluate instead of infection, maybe, clinically, we're just missing something. We're going to review the culture results, consider MRSA if it wasn't deescalated, and then assess the need for revacularization. If he is improving, then we're going to adjust the antibiotics accordingly, take them back, close and close follow-up with a reconstruction or bracing.
TAPE ENDS - [33:16]