Diabetic foot ulcer (DFU)

My name is Martin Arissol, I’m a vascular podiatrist, I work in major hospital in London. My skills are in treating the diabetic foot, vascular pathology and particularly wound care management.  I work in a number of clinical settings. I work predominantly on a ward,  supporting vascular surgeons, medical doctors, and also I support my colleagues in the outpatient clinics and in community settings.

We try to use STIMULAN in cases which are most challenging. So, for instance, patients who can’t tolerate oral antibiotics or find taking an oral antibiotic regime challenging to their daily lives. Patients who have deep wound cavities that obviously are challenging in a microbiology sense, and so using STIMULAN mixed with antibiotic can actually act on the wound directly at the point of infection. In cases where patients where medical therapy or conventional therapies are not working for the patient, we would switch that therapy to a STIMULAN product with an antibiotic mixed and targeted it to the organisms that are growing in that wound.

We use STIMULAN to fill wound spaces and wound voids. And we use STIMULAN as a carrier to deliver antibiotics locally to treat a zoo of pathogens that cause that environment around the wound.

The types of cases that we use STIMULAN in are the most challenging cases.  For example, those things may be the patient has had previous MRSA infection, C. difficile or liver impairment, so we reduce the risk of a toxicity to organs of the body. In areas where we can’t deliver intravenous antibiotics to a patient and it’s not suitable, for instance, a patient may have antibiotics delivered at home through a cannula or a PICC line. But if there’s a risk of infection in the cannula or in the PICC line, we can’t use those lines. So we would choose STIMULAN as a choice, as a carrier, to use a local therapy.

So our typical treatment pathway would be assessing the patient’s suitability for debridement or amputation of a wound and then we would choose our antibiotic based on the microbiology samples grown from the deep tissue samples. This would be discussed with an MDT, an infectious diseases consultant, and then we would pack the wound cavity and using STIMULAN as a carrier to deliver those antibiotics at that wound base.

The way we prepare STIMULAN is in a number of settings, and it can be done by myself, a podiatrist, a surgeon, or a clinician that’s trained in using STIMULAN. This can be done in a theatre setting, which we’ve done before, bedside on a ward, or in a clinical setting in a sterile field environment.  We usually make the beads at the time of when we need them, so they’re at the bedside or in theatre or in a clinical setting of when we need to pack them into a wound.

Our antibiotics are targeted and the choice is made purely by the sensitivities grown from bone or tissue samples sent to the lab for culture.

So we make the beads at the time we need to use them on the patient and the patient’s prepared, ready for the beads to be actually transferred into the wound.  This can be done in the theatre setting, which we have done on many occasions, a bedside setting on the ward or in a clinical setting where the patient is prepared in an aseptic technique in a sterile environment.

We use a low contact dressing over the top of the beads to seal them in, and we use this because it allows the exudate to breathe through the dressing, allows us to manage the exudate through secondary absorbent dressings on top of this area here. That low contact dressing is sealed into place with Mefix tape or a type of tape that you want to use.

So typically we see beads lasting up to about eight weeks but we know from the data that the elution time is roughly about six weeks for gentamicin or vancomycin. But I’ve seen beads in wound environments up to about eight to nine weeks and I think it all depends on the wound environment itself.  You’ll get faster elution times with a wound that’s more moist rather than dry.

Personally, I don’t ever change the beads in the wound unless someone’s taken them out and thrown them away. Typically, 10cc of STIMULAN used with an antibiotic usually is enough to pack into a wound, into a void cavity and the elution time is enough to treat an infection.

The answer to this is twofold because we use two types of clinical examination. One is diagnostic and one is visual. Diagnostic examination would be an x-ray to look at the bone structure, look how the bone is forming around the beads and if there is good bone healing. And then the other is blood profiling.  We would look at patients’ inflammatory markers to make sure there is no infection ensuing. And also we would check for vancomycin and gentamicin levels if we’re using those antibiotics, either one or the two to see what the levels are. The other clinical inspection would be to visually look at the patient’s foot.  We would also do a clinical inspection of the wound to check for any signs of cellulitis, tracking infection, and looking for granulating tissue that starts to develop around a wound.  So the beads will actually elute quite quickly and so you should be able to see some of this developing around the edges of the wound.  If after six weeks you still have bone involvement or there is still bone visible at the bottom of the wound, I would question whether you would repack that wound.  I would suggest that you would think about maybe the organism’s not been targeted at the time, or the patient needs to go back to theatre to have some dead tissue or bone removed.

Once the beads are in place, I personally would recommend you monitor a wound, someone with experience using STIMULAN monitors that wound, because the levels of exudate from that site are different to what you would normally expect from a normal healing wound without using STIMULAN.  You would need to see the patient at least twice a week for wound dressing changes because the high levels of exudate are high within the first one to two weeks, and I would also recommend that you do blood profiling to make sure there’s no clinical infections, such as inflammatory markers.  The other thing we do is check the levels of antibiotic within the blood serum levels as well to make sure they’re not off the scale and making sure you’re protecting the body from systemic toxicity.

In all the cases that we’ve treated till now, we’ve seen minimal traces of antibiotic serum levels in blood profiling.  It’s to the point now we’re not regularly testing for that level of antibiotic in the bloodstream.

This is a question I get asked a lot and it’s quite an important question actually because it’s the level of exudate you see from a wound with STIMULAN in is totally different and looks different to a wound that a clinician would see on a normal wound without STIMULAN.  So this rich yellow foamy liquid actually has vital products that help in wound healing and I do advise and teach my colleagues not to remove the beads because if you remove the beads and wash them in saline you’re washing away the vital products for wound healing anyway.  So I normally advise patients and clinicians to keep the beads in as long as possible unless they’re really concerned that there’s a clinical infection happening around the wound.  So the beads stay in for the duration of the elution time, which could be up to six weeks.

The common mistakes I see from clinicians is the fact that they are too quick to take the beads out because they think there might be an infection happening behind the beads or the wound needs debriding because there’s a change in the visual tissue appearance.  With the high levels of toxic antibiotic and the calcium sulfate embedded in a wound,  the wound bed appearance seems to look like a blanched effect or bleached effect, which often looks like sloughy tissue.  So clinicians often make the mistake of trying to remove this tissue, which actually in fact, if you left for 48 hours, would return to normal, healthy granulated tissue.

To date, personally I’ve treated 26 cases successfully with a 70% success rate of healing within 12 weeks using STIMULAN and an antibiotic therapy.

In the last 16 years of treating diabetic foot wounds, on average I would see healing times, if patients were going to go on to heal, up to 26 weeks, 30 weeks.  But with the cases I’ve personally seen and applied STIMULAN to, we’ve seen healing times up to 12 weeks, which is significantly lower than what we’ve previously seen.

We don’t use topical negative therapy with STIMULAN purely because we want the antibiotic carrier and the antibiotic to stay within the wound environment and to be eluted into the tissue and the bone. If we use topical negative pressure, I believe we would be removing some of those vital products to treat that wound.

The biggest reason we use STIMULAN is to avoid or prevent the overuse of antibiotics on patients who are vulnerable.  There is a huge antimicrobial resistance crisis around the world and the less antibiotics we use on patients,  the less resistance we get, and the more choices we get to use on organisms that are preventable diseases.

I think there’s definitely a potential for using STIMULAN in a community setting in chronic wounds,  wounds that have a chronic infection, chronic biofilm, and that’s organisms that get locked in a biofilm that systemic is systemic antibiotics can’t reach and also you can’t treat topically with conventional dressings so we could prevent chronic infections turning into acute infections by possibly using antibiotics early enough on those areas.  I’ve seen STIMULAN working on biofilm, it does break down the biofilm and it does treat the organisms that are locked in that biofilm.  If we could target those patients with the chronic wounds, diabetic foot ulcers early enough, we may prevent patients coming into hospital with acute problems and having amputations.

There is a UK consensus group made of podiatrists, surgeons, and physicians that have written a pathway for use of antimicrobials in diabetic foot wounds.  This can be found easily on the websites, so just do a search.