Debridement of wounds
Figure 1 Debridement is one of the central aspects of wound care. Lack of adequate debridement is one of the main reasons for delayed healing in chronic wounds. In the image above, a large wound following a severe soft tissue infection is debrided with a scalpel and forceps. Credits: Casa Nayafana Shutterstock
Chapters
Introduction
One of the biggest challenges in wound care is the lack of understanding of how important debridement is or a lack of knowledge about how to do this safely. There is also much uncertainty about how much debridement can be carried out by a nurse or medical assistant and what should be done by a medical doctor.
A chronic wound will start healing properly once necrotic tissue has been removed. The most effective way to remove this is by sharp debridement. Many caregivers have a high threshold for taking a sharp instrument and starting to scrape a wound. This is primarily due to a lack of training, sometimes for fear of causing the patient discomfort or causing a complication.
Learning how to debride a wound is one of the most important skills to teach those dealing with chronic ( and acute) wounds. This is not something you can just read about and do—it is a practical skill where you should have a mentor by your side as you learn the procedure. There are some good videos online that show how a debridement is done, but the best is, of course, if you practice this under the guidance of a patient.
So, how aggressively can a nurse or a medical assistant perform debridement? This question is difficult to answer in one sentence as it depends on a number of factors. What level of experience does the person have with debridement? Is there a doctor available in the area who can perform a deeper debridement? Do you have local anesthesia available, and have you been trained to use it?
Also, in Western countries, there is a grey zone between what a nurse or medical assistant can do and what should be done by a doctor who may have a more profound understanding of the anatomical structures nearby. At the tissue viability clinic where we work, the nurses do most of the debridements at the outpatient clinic, while surgeons perform deeper debridements in the operating theatre.
Usually, debridement is a reasonably safe procedure as long as you only remove dead tissue. Usually, it will bleed a little when we debride, and on occasion, it may bleed more, but this can be stopped by compressing the bleeding site with a cotton swab for at least three minutes. Do not be tempted to look underneath the swab before a full three minutes have passed- otherwise, you may start all over again. It is beneficial to have a general understanding of the anatomic structures close by. For example, when debriding deep wounds in the groin area, there are large vascular structures that can bleed profusely if damaged. When debriding a pressure ulcer in the sacral region, be aware of the ischial nerve, which can lie close to the wound bed. Damaging this nerve can cause severe loss of motor and sensory function in the limb. When debriding a wound that lies over a joint, you will have to know what the joint capsule looks like. You have to avoid opening this capsule at all costs, as this can lead to a devastating infection of the joint.
Remember that it is often painful for the patient to get their wound debrided. The exceptions to this are, for example, patients with severe sensory neuropathy due to diabetes or syphilis- here, we can usually debride without the patients having any discomfort. Before we look at debridement methods, we must address how to deal with pain during debridement procedures. Giving the patient oral pain medication about 45-60 minutes before the procedure can be helpful. Paracetamol + Codeine is usually sufficient in most cases. Please refer also to our chapter on "pain treatment" in general.
Dealing with pain during debridement
Paradoxically, many caregivers do not take decisive measures to make the debridement as "comfortable" as possible for the patient. Not seldom are patients asked to bite their teeth together and tolerate the procedure a little longer- " I am soon finished" is something we hear a lot as caregivers scrape away at the wound. Not all patients are good at giving us feedback about their pain. Especially older men often believe they must tolerate the pain we bring upon them. We have made a short list of measures you can use to make the procedure as comfortable as possible.
1. Create a calm atmosphere in the treatment area. The patient will sense it straight away if you are nervous. Even if you have a hectic schedule that day, it is essential that you take some time here. Get rid of curious bystanders- but it may help to hold a hand from a loved one or a friend during the procedure. Some patients feel safer if they are in control and can follow the entire procedure. Other patients feel very uncomfortable if they see someone scraping their wound; in this case, you will need a cloth barrier. Patients are very different in this way, and you should ask them about their preferences before you start. In our experience, most patients prefer not to have a visual barrier but relax with their eyes closed and can take a peek whenever they feel like it. In this manner, most patients think they stay in control of what is going on.
2. Try to have all the necessary equipment close by and that everything is prepared beforehand. It will only add to the patient's nervousness if you constantly jump up to get a new instrument or, even more so, if you constantly leave the room to get something.
3. Explain to the patient what you will do before removing the old dressing. Something that would calm the patient would be to say: " Now, we shall carefully remove the old dressing and take a look before we do anything else." Once you have removed the old dressing and see that the ulcer has deteriorated and is full of sloghy necrotic material, do not roll your eyes and exclaim: " Oh my goodness, this looks terrible, this is the worst I have seen". Instead, keep calm and say, " Now let us give this wound of yours a good rinse and then see how we can clean it up." We are exaggerating a little here to get our point across, but such scenarios exist in wound care.
4. As we remove the old dressing, you will already get some indication of how sensitive the patient is. If the patient is very afraid, then even a careful loosening of the dressing can cause visible discomfort. It is, therefore, essential that we do everything to make the patient feel safe in our care. If the patient feels much discomfort while removing the old dressing, you can be sure that a sharp debridement is difficult without local anesthesia.
5. Before touching any sharp instruments, give the wound a thorough rinse with body-tempered water—you can usually use boiled tap water or saline solution for this. Gently dry the woundbed with cotton gauze.
6. If the patient at this stage has shown no discomfort during removal of the dressing and the rinse of the wound it may be possible to gently debride without any use of local anesthesia. Inform the patient what you are about to do and that they can take a " time-out" at any point.
7. In wound debridement, it is very common to apply local anesthetics directly to the wound bed.
There are several different formulations for this use. Remember that all local anesthetics are toxic at high doses. This is something that some caregivers surprisingly often oversee! Even though applying it topically rather than injecting it into the tissue allows for higher dosages, we usually use the exact dosage restrictions for topical use as we would for injections to be on the safe side. There are reports of lethal toxic reactions that have occurred when large amounts of topical anesthetics were applied to open wound surfaces ( for example, burn patients)! Another essential thing to remember is that numbing creams like Emla and tapin have strict dose restrictions because they are absorbed more readily. They should be used with extreme caution in children under three years of age because of toxic reactions, and they are contraindicated in children under the age of 12 months!
a) Dripping lidocaine into the wound
The simplest method is to drip lidocaine solution ( the same type we use to inject) onto the wound bed. If you have the 2% solution available, this will work better than the 1% or weaker formulations. It usually works quite fast - within about 5 minutes, the nerve endings in the woundbed will be somewhat numbed. It doesn't work very deep, however. Once you have debrided superficially, it is usually wise to drip more lidocaine into the wound before debriding more. Because these local anesthetics have a low pH, sometimes patients will feel a burning sensation as this is applied. Usually, this side effect quickly goes away as the numbing effect sets in. Note: there are also lidocaine sprays available - these are often used by ear-nose-throat specialists or before endoscopic procedures like gastrocopies. Some sprays are not ideal for open wounds as they contain other substances like flavorings. We have experienced that one type of lidocaine spray with banana flavor caused a severe burning sensation to the patient when applied. We, therefore, recommend that you avoid these sprays unless they only contain lidocaine or an equivalent.
b) Applying lidocaine gel to the wound
It is very common to apply lidocaine (xylocaine) gel to the wound bed and let it work for about 30 minutes before trying the debridement. This penetrates slightly deeper than method a), and if you do a gentle debridement, this method is usually adequate for the majority of your patients. Lidocaine gel is fairly cheap.
c) Applying numbing cream to the wound
Even more effective are local anesthetic creams like Emla or Tapin cream. These numbing creams are often used, for example, to numb the skin on children's hands/arms before setting an IV cannula. When used to numb a wounded, they should also be left in place for 30-45 minutes before the procedure. The advantage of these numbing creams is that they penetrate deeper into the wound bed than lidocaine gel. This often allows us to debride somewhat more "aggressively." However, you must know that the manufacturers do not approve of these numbing creams used in open wounds! A vast global community of wound care professionals uses this product in open wounds, nonetheless, due to a lack of better alternatives. We have also used this method for over 20 years and have never experienced any adverse effects. But the bottom line here is that if you apply these products to an open wound, this is considered " off-label" use, and you are doing so on your own responsibility. These numbing creams are usually much more expensive than regular lidocaine and are generally unavailable in clinics with low resources. As we mentioned earlier, because these numbing creams are absorbed through the skin, there are strict dosage restrictions, and you have to be especially careful when using them on children under the age of 3 years. These products are contraindicated in children under 12 months!
Figure 2 An overview of some local anesthetic products that can make debridement less painful. On the left, we have the injectable form of local anesthetics ( here Lidocaine and Marcaine), which can be repeatedly dripped onto the wounded as we debride. In the middle, we have numbing jelly-like Lidocaine2% or Lignocaine %. On the right, we have numbing creams, which are more efficient as they penetrate more deeply into the tissue. These are usually a mixture of lidocaine and prilocaine. Be aware that all local anesthetic products are toxic when applied at a too high dosage. Read the package insert carefully and never exceed the dosage recommendation Also, the products on the right are not approved by the manufacturers for use in open wounds s. When using these in wound care, we do this as " off-label-use at our own risk. Emla and Tapin should be used cautiously in children under three years and never in children under 12 months!
8. topically applied numbing products are often insufficient when we do a deeper debridement. In these cases, we usually use injectable forms of local anesthetics. This should ideally only be done by a medical doctor or a nurse with a medical doctor close by. Obviously, in very low-resource areas, a doctor may not be available, and trained medical officers or equivalent may have to do this on their own. Remember that some patients may have severe allergic reactions to this substance, although that occurs rarely. Always ask the patient beforehand if they have received injections with local anesthetics earlier and how they reacted. An excellent tip is to inject the local anesthetic through the necrotic tissue - ideally, you want to numb the area just behind or below the necrotic layer. This requires multiple injections, maybe up to ten or more, for an ulcer of about 10 cm2. If you do this gently, advancing the needle carefully is hardly painful for the patient. If you, however, set the injections the traditional way, through healthy tissue around the ulcer, this will usually be very painful to the patient. Occasionally, we have to use this method, but in most cases, the "through the necrotic layer" method of injections is applicable and more gentle! We try to use the thin needles we have, although this makes it hard to push the solution through the syringe and puts a strain on our fingers.
9. Sometimes, there will be a need for a more thorough debridement at the hospital level, especially when there are signs of severe infection or bone/joint involvement. This will have to be done in either sedation, a nerve block, spinal anesthesia, epidural anesthesia, or general anesthesia ( narcosis). Remember that even if the patient is elderly and frail, there may be a need to get the patient hospitalized for a few days to do a proper debridement.
10. As we mentioned earlier, if we know that the patient is very anxious and scared, giving the patient some painkillers about 45-60 minutes before the debridement procedure is beneficial. A combination of paracetamol and codeine is a good choice here. Alternatively you can give Tramadol (Ultram). In some instances, you may even have to provide the patient with opioids. 5- 10 mg Morphine orally can be used for adults 30-60 minutes before the procedure and lower doses for children.
Methods of debriding
Autolysis
Autolysis means to "dissolve by itself." In wound care, this refers to the body's mechanisms for dissolving dead ( necrotic tissue). In typical wound exudate, which the body produces, several powerful enzymes ( proteinases) gradually dissolve the necrotic tissue. These enzymes need a moist wound environment to work, which is also one of the reasons moist wound care is generally recommended. If the wound is to dry- most of the healing processes come to a halt and the wound may even deteriorate. Gels, honey, and foam dressings are usually good choices to keep the wound environment adequately moist. Remember, most of these products do not contain any active substances that dissolve the necrotic tissue. These dressings work because they provide a perfect environment for the enzymes and other cellular functions to heal the wound. However, a few handful of dressings speed up the autolytic process signifcantly - Polymem is an example of such a dressing. It contains glycerol and a surfactant, and when applied to necrotic wounds, the autolytic cleaning process is activated after just a few days of use.
A particular variant of speeding up the autolytic processes is by using occlusive dressings. We mean occlusive dressings that do not "breathe" very well. They are not entirely airtight but have very little permeability. Usually, self-adhesive hydrocolloid plates are used for this ( for example, DuoDerm). They create a warm and moist wound environment, which the proteinase enzymes love, and that can speed up the autolytic process manifold. However, most types of bacteria love this environment as well. With such an "airtight" dressing, you create an anaerobic environment, which many of the most pathogenic bacteria love even more! So please, do not use this method in Africa! And never, ever use it on a patient with diabetic foot ulcers - that would be risking the patient's limb and life. We consider this not a safe method at all. Yes, we know that it can be used with success, but we have also seen catastrophes leading to septicemia and, ultimately, the death of the patient. That being said, hydrocolloids deserve their place in wound care. They can, for example, be used to protect areas of skin from shear and friction. They can also be used for very superficial, clean wounds.
Regardless of which dressings we use, autolysis is a relatively slow process. It may sometimes take weeks or months before a wound is cleaned of necrotic tissues. Only when most of the necrotic tissue is gone can the wound start to heal. That is why, in addition to autolysis, we often need faster debridement methods.
"Dry to wet" debridement
This is a very commonly used method. For example, we use this principle when we use polyurethane foam dressings. We apply the dry dressing onto the wounded, gradually absorbing the moisture while providing a moist environment. This is often a perfect environment for autolysis. It works well when there are low-moderate amounts of dead tissue. If there is much necrosis, however, this process is usually slow, and as the dead tissue slowly dissolves, a foul smell can be a problem. In these cases, we have to change our tactics.
"Wet to dry" debridement
This method involves placing a slightly moist gauze into the wound and letting it dry for a few days. At this point, it will usually have adhered to the wound, and when we remove the dressing, we tear some of the necrotic tissue with us. There are several obvious disadvantages to this method. Understandably, removing the dressing can be very painful for the patient. Secondly, the drying out of the wound halts the autolytic enzymatic activity and may even desiccate ( dry out) and kill healthy tissue. Thirdly, this method is ineffective at removing more significant necrotic tissue. Fourthly, in wounds with moderate-high secretion, it will not work anyway because the dressing will always be moist.
The "wet-to-dry" method goes against modern wound care principles, and it was abandoned by most caregivers at least 10-15 years ago. Strangely enough, it still has some followers who are unwilling to give up on this method. Some of the followers who adhere to the technique of wet-dry debridement are highly regarded professionals in the field of wound care. To be on the fair side, many years ago, we also used this method, and not seldomly with success. So, it would be wrong to say this method does not work. In the right wounds, at the right time, and in the right hands, excellent results concerning wound healing may be obtained when there is little necrosis. Concerning how effective it is for debriding wounds, we are more doubtful. The problem is that sometimes, it can do the opposite and delay wound healing. It may be challenging to foresay which wounds respond best to this and which do not. A more modern, moist wound healing approach will work better in most cases.
Dale et al. published an excellent article in 2011 titled "Say Goodbye to Wet-to-Dry Wound Care Dressings: Changing the Culture of Wound Care." If you are interested in this topic, we strongly recommend you read the article, which highlights several key points of why this method should be abandoned.
Incidentally, there are times when we certainly try to turn a very wet wound into a more dry wound. In fact, whenever we have a wound with high exudate, we instinctively aim at drying out the wound more. This is not the same as wet-to-dry debridement! Trying to get control over the exudate by placing dry products into the wound bed and changing them frequently is simply trying to reduce the exudate to more normal levels.
Other situations where we want to keep the wound dry are vascular ulcers with dry eschar, especially on the feet. If we have a patient with poor arterial circulation and dry necrosis on the feet and no signs of infection present, we want to keep the necrosis dry! If we moisten these dry necroses, they will become a moist slough, start to smell, and can easily lead to infection. Again, this has nothing to do with wet-to-dry debridement. We mention it here to point out that sometimes, just sometimes, we want to dry out a wound or keep it dry.
Figure 3 Dale et al. published an excellent article in 2011: "Say Goodbye to Wet-to-Dry Wound Care Dressings: Changing the Culture of Wound Care". If you are interested in this topic we strongly recommend you to read the article, which highlights several key points of why this method should be abandoned. Click on the image above to get to this link. image copyright: homehealthcarenow
Although we see this method as outdated, we will briefly explain how it is usually carried out. Normally cotton gauze is used for this purpose. A pieze of cotton gauze or an appropriately sized cotton swab is formed so that it fills the ulcer well. It is slightly moisturized with 0,9%saline solution, or 0,9%saline gel is applied on the side towards the wound bed. The cotton should be moist but not dripping wet. Important: whilst we generally recommend using clean tap water or boiled water for rinsing wounds, we do not recommend using this to moisten dresings which are to stay in the wound for a period of days.
Once the moistened gauze is placed in the wound it is covered with a dry dressing, often also gauze. A roll of gauze is used to hold the dressings in place. During the course of a few days the inner dressing will have dried out ( unless the wound has a lot of exudate). Dressing changes are usually done every 3-4 days. The inner gauze will adhere to the wound bed and upon removal will tear with it some of the necrotic tissue.
Figure 4 "Wet to dry" debridement. A slightly moistened cotton gauze is placed into the ulcer and covered with dry cotton gauze. A roll of cotton gauze holds the dressing in place. This type of debridement, although sometimes successful, is rarely used today. Copyrights ( all images): Dr. Ido Weinberg (angiologist.com)
Debridement using abrasive pads/cloths
Several debridement pads or cloths have come on the market in the past years. These products have in common that they have a slightly abrasive surface. When the product is rubbed over a woundbed some superfiscial debridement is achieved. The technology is similar to microfibre cloths, which many of us have in the household today for cleaning purposes. The material has many tiny monofilament nooses, significantly increasing its surface area. Most pads have a core made of some absorbent foam. Necrotic debris and microorganisms adhere to the material.
Pads/cloths for debridement are single-use- they cannot be washed or sterilized and must be disposed of after use. Also, if a patient has multiple wounds at different anatomical sites - please use a new pad/cloth at each site to avoid cross-contamination of bacteria from one wound to another in the same patient. As an example, a bedridden patient was unfortunate enough to sustain a pressure ulcer in the sacral area and the heel. We expect more intestinal bacteria like enterococcal species to be present in the sacral area than in the healing ulcer. It would, therefore, be unwise to use the same pad in both wounds. If you have two ulcers near each other, you may use the same pad in both as long as they appear similar.
Even though we are rubbing the wound bed with these products, they are surprisingly gentle, and very often, the patient has no or only little discomfort during the procedure, as long as we don't use unnecessary pressure. The pads/cloths must be moistened with a suitable rinsing agent. This could be anything from boiled water (clean tap water), 0,9% saline, or antimicrobial solutions like super-oxidized water, a 2% vinegar solution, or a polyhexanide solution, to name a few. Note that some cloths are premoistened - usually with a solution containing a mild surfactant ( a soap-like substance).
These pads/cloths are less effective than sharp debridement with a curette or scalpel. However, They are a safe alternative for caregivers who do not feel competent enough to do a sharp debridement. Do not expect miracles - you cannot simply rub away thick necrotic tissue. However, these products do work very well when there is some superficial slough, and we believe it is an effective tool for removing biofilm when used repeatedly. If there is much necrotic tissue, you must consider a sharp debridement first, especially if there are also signs of infection.
To be honest, when these pads/clothes first came on the market, we were skeptical. In fact, we ignored the first products that appeared and thought that these products were just another way for companies to make money off wound care. However, once we started using these products routinely, we actually were impressed. Obviously, debridement pads are not as effective as a sharp tool. However, they actually do remove superficial necrotic tissue, and upon repeated use at every dressing change, you will see a significant improvement. Maybe the most important aspect is that the procedure is usually almost pain-free for the patient.
Debridement pads and cloths are also convenient for removing dry, flaking skin and are very suitable for cleansing acute wounds.
Most suppliers of debridement pads/cloths advertise their effectiveness for removing biofilm and that there is clinical documentation for this. Basically, any mechanical agent rubbing against the wound bed will aid in removing some of the biofilms, so this is not surprising. Debridement pads are not a magical antidote to biofilm. However, the repeated use of these products may absolutely help keep biofilm at bay.
If you have read some of our other chapters, you will have noticed that we are somewhat allergic to the excessive attention that biofilm receives. The problem with this focus on biofilm is that it sometimes takes away attention from other important aspects of wound care. While biofilm can undoubtedly be a problem for some wounds, poor blood circulation, inadequate compression bandaging, and lack of offloading are much more significant challenges. The point is that it's good to reduce biofilm occurrence with pads and cloths, but it must not distract attention from other important aspects of wound care.
If a patient has multiple wounds, a pad or cloth should be used for each wound to avoid cross-contamination unless the wounds are more or less contiguous. This is a single-use product.
Figure 5 Some of the debridement fiber products available today: From left: Debrisoft, Debriclean, Prontosan Debridement Pads, and UCS debridement cloths. Many other producers have developed similar products, and wound care providers have adopted this debridement method. Most of the debridement fiber products need to be moistened before use. Usually, regular saline is used for this, but you can, of course, also use other wound cleansers for this purpose. UCS cloths are pre-moistened with a surfactant ( a gentle soap).
Video 1 A video by Lohman & Rauscher about their debridement product Debrisoft. Click on the image above to view the video on YouTube. Copyright Lohman & Rauscher
Video 2 A video by Medi UK about their product UCS debridement cloth. These cloths are pre-moistened with a surfactant and glycerine. Click on the image above to view the video on YouTube. Copyright Medi UK
Figure 6 This patient was treated at our clinic for challenging auto-immune ulcers. The ulcers were very painful, and sharp debridement was not well tolerated due to discomfort, even when numbing with lidocaine gel. We resorted to using a debridement fiber product at every dressing change ( twice weekly), eventually cleaning the ulcers nicely (without pain), and healing commenced. We used Prontosan irrigation solution to moisten the pads. The auto-immune disorder was addressed by topical application of tacrolimus ointment at each dressing change.
Figure 7 If you use a debridement fiber product that comes dry from the package, you must moisten it before using it in the wound. In areas where municipal water from the tap is considered safe, you can use this for most types of wounds. In most areas of the tropical world, this will not apply. Here, sterile saline irrigation solutions are the most affordable choice. If available, it makes sense to use an irrigation solution that contains a mild surfactant to aid in loosening the slough. However, regular saline works fine, too. At our clinic, we often also use a weak vinegar + surfactant solution for this purpose.
From left to right: 1. municipal tap water, 2. 0,9% NaCl irrigation fluid, 3.Prontosan ( surfactant + antimicrobial),4. Octenilin (surfactant + antimicrobial, Optima pH ( 2% vinegar + surfactant).
Figure 8 In low-resource areas in Africa, debridement fiber products are unavailable due to their price. A workaround solution is to use regular, household microfibre cloths! These clothes use a technology that is very similar to that of special debridement fiber products. Household microfibre cloths can be purchased cheaply, boiled in water, dried in a clean environment, cut into pieces of adequate size (using an aseptic technique), and stored in a clean, closed container. Obviously, homemade debridement cloths are single-use and must be disposed of after use.
Figure 9 In low-resource areas in Africa, commercial irrigation solutions for wound care containing surfactants are usually not affordable. A simple recipe for a homemade solution is to add five drops of baby shampoo or bath to 100ml of NaCl 0,9% irrigation solution. Note that commercial irrigation solutions usually contain conservatives to extend their shelf life. However, your homemade solution should be used the same day, not stored. Incidentally, it is not a coincidence that it is the Johnson baby shampoo we have in the picture here - it has a long track record of being dermatologically tested. But another major brand of baby shampoo or baby bath product will do.
Enzymatic debridement
Wouldn't it be fantastic if we could apply something to the wound that would dissolve all necrosis without the patient feeling pain? Unfortunately, it does not exist yet. Those who have treated wounds for a long time will remember a substance called Streptokinase (previously marketed under the name Varidase®). This powder contained the same enzymes that streptococci use to break down tissue. We mixed this with water and applied it to the wounds. It may have had some effect. Streptokinase was mainly used for intravenous treatment of blood clots in heart attacks; newer thrombolytic medications have mostly taken over. There are still some who continue to use it in wound care.
Various ointments contain enzymes that may aid in speeding up the autolytic processes that gradually break down necrotic tissue. Some contain collagenase ( Iruxol, Santyl), others fibrinolysis and or deoxyribonuclease (Elase). Others contain Papain from Papaya fruit ( Accuzyme). How effective are these products? To be honest, we do not know because we have never tried any of these enzymes apart from Streptokinase. We do not doubt that these products speed up autolysis slightly, but that sharp debridement is still superior. And with debridement pads being widely used we are not sure which how often you would need enzymatic debridement. In today's world, where news about excellent products spreads quickly through social media and other channels, we would have expected to hear more about these enzymes if they were highly effective.
However, there is one highly potent mixture of enzymes that can dissolve necrotic tissues in a matter of a few hours! This mixture is found in the saliva of certain types of fly maggots, for example, in green bottlefly maggots. To dissolve tissue effectively, many enzymes have to work synergistically. At least 16 highly effective enzymes are found in the saliva of fly maggots, making it so potent. Various research laboratories worldwide are working diligently to isolate the enzymes fly larvae use to dissolve dead tissue. However, the challenge is that the larvae use a complex cocktail of enzymes, making it difficult to produce these synthetically. We believe this will play a central role in the future of wound care. In 10 years, we will probably use a synthetic cocktail of fly larvae enzymes to clean many wounds.
Figure 10 Some of the enzymatic ointments available. From left to right: Streptokinase, Accuzyme (papain), Iruxol Mono (collagenase), Santyl (collagenase), Fibrinolysin ointment ( fibrinolysin -obviously :), Elase (fibrinolysin + deoxyribonuclease)
Using natural fruit enzymes for debridement
Papaya fruit contains papain, an enzyme that aids in autolysis. Papain ointments can be bought, but they are quite expensive and not a realistic option in low-resource areas. Globally, there are many reports of using fresh papaya fruit and applying it to wounds to aid in debridement. Its use is most likely under-reported.
The use of papaya in wound care dates back a long time, and in many areas of the world, it is used actively in both traditional medicine and clinics and hospitals. On the internet, you will find many reports and minor studies on all types of wounds, from diabetic foot ulcers to burns.
Papaya fruit is readily available in most areas of the tropics. The green, unripe fruit appears to have a higher papain content and is considered better for wound treatment than ripe fruits. Comments from the users of papaya suggested that topical application of the unripe fruit promoted desloughing, granulation, and healing and reduce odor in chronic skin ulcers. It is undoubtedly cost-effective. There seemed to be few side effects, but the patients occasionally reported a burning sensation. There was concern about using a non-sterile, non-standardized procedure, but we have found no reports of wound infection. Papaya is widely used by nurses globally as a form of dressing for chronic ulcers, and there is a need for standardization of its preparation and application. Preparing the pulp for application in a wound requires an aseptic manner.
Many users of papaya pulp report that they apply the pulp to the wound cover it with gauze and leave it on for 2-3 days. If you have a more critical wound, changing the papaya pulp dressings daily may be wise.
Figure 10a Papaya fruit is common in most parts of the tropical world. For wound debridement, the pulp of the green, unripe fruit is more effective. Credit: topnmp/Shutterstock
Figure 11 If you google " papaya dressings wound care," you will find several studies documenting its efficacy and safety. The article above is by Vasuti et al. and was published in 2017. Click on the image above to get to a full-text file of this article. Copyright: Vasuti et al.; International Surgery Journal
Debridement with curette/ ring curette
This is the most common form of debridement. If we had to choose a single instrument for debriding chronic wounds, it would be this one ( although we would sometimes miss our scalpel).
In the past, most caregivers used a curette that could be sterilized, but these became dull over time. When you work with a dull curette, it not only makes the removal of dead tissue more difficult, but it is also more painful for the patient. It may sound paradoxical, but the sharper your tool is, the less painful the debridement. Just think of your razor, which you use to shave your face or legs - a dull razor is significantly more uncomfortable. For this reason, disposable curettes are often used for debridement. However, these are costly and will most likely not be available in low-resource areas. In that case, you must resort to using re-sterilizable stainless steel curettes.
Most single-use curette blades have two sides. Depending on which side of the ring one uses, they have a very sharp edge on one side (to cut away necrosis) and a less sharp edge on the other (to "brush away" fibrin and loose dead tissue). Note that there usually is a mark on the handle showing which side of the blade is razor-sharp. When this mark is on the up-side of the shaft, the sharpest side of the curette is facing the wound. Single-use curettes cannot be sterilized. They must be disposed of in a container for sharp instruments after use.
Figure 12 Stiefel curettes were long known to be the gold standard of single-use debridement curettes because they are super sharp. They are the "Gilette" blade of debridement. Today, several other manufacturers sell equally good curettes.
Figure 12a Single-use curettes usually have a razor-sharp side and a blunt side. The sharp side is excellent for removing the necrotic tissue, and then the blunt side can be used to scrape it together and remove it from the wound. Remember, the sharper your tool, the less painful the debridement is - remember the analogy to a razor you would use at home. Most single-use curettes have a small mark on the handle to indicate the sharp side. The sharp side is towards the wound bed if the mark is on the upside.
If one does not have a curette, a scalpel can be used to scrape over the wound. It is not as effective as a ring curette but works fine in most cases.
Often, debridement must be repeated at each dressing change ( serial debridement), and the wound eventually becomes clean little by little.
Debridement using a scalpel
Many would consider this a task for a doctor, especially if one needs to remove larger areas of necrosis. Good anesthesia may be required with local anesthesia or sedation/anesthesia in a hospital setting. Often, one also needs forceps to hold the tissue while cutting. The plastic forceps found in most disposable kits are poorly suited for holding tissue during a revision, and we recommend acquiring either good-quality disposable metal forceps or forceps that can be sterilized.
Figur 13 Standard scalpel (top) and disposable scalpel (bottom). We recommend using a No. 15 blade for the debridement of more minor wounds, as it provides better control. Remember that suitable forceps are essential for the grasping tissue to be excised. A surgical forceps has small teeth at the tip to give a better grip on the tissue. Credit Hupp JR
Figure 14 The definition of a surgical forceps, as opposed to other medical forceps, is that it has small teeth or serrations at the very tip, providing a better grip on the tissue.
When the patient is under sedation or even spinal anesthesia/blockades/general anesthesia, it is imperative to take the opportunity to clean the wound as thoroughly as possible. This may even mean cutting into healthy tissue to remove all necrotic tissue.
Figure 15 Slightly curved scissors can be helpful for the debridement of thicker parts of the slough, which forceps can pick up. A good pair of forceps is essential. Credit Sergii Votitt Shutterstock
Video 3 There are many good educational videos about surgical debridement on both YouTube and Vimeo. Due to recent changes to policies concerning graphic material, you will have to sign in on these channels to view the films. Click on the image above to get to an excellent video by Dr. Nick Campitelli, where he is debriding ulcers secondary to pyoderma gangenosum. Remember that pyoderma gangrenosum is a severe condition and should only be treated by experts. Debridement without concomitant immunotherapy can make the situation worse. Copyright: Dr. Nick Campitelli.
Ultrasonic mechanical debridement
You may have seen commercials for modern toothbrushes using ultrasonic high frequencies, or you may even use one yourself. The toothbrushes vibrate about 60.000 times/minute and have good documentation for superior cleansing abilities. What about using the same technology to cleanse and debride a wound? That is precisely what Curasonix has done. They have developed a debridement device - Curason ( that looks similar to a toothbrush) for wound cleansing. We have not tried this device yet and are unsure where it is priced. The brush heads are single-use and have to be discarded after use. Once we have tried this product, we will give you feedback about our experience.
Video 4 The Curason device from Curasonic uses ultra-high frequencies to cleanse wounds. Click on the image above to view the video. copyright: Curasonix
Debridement with hydrosurgery
The Versajet ( Smith & Nephew, Hull, UK) is a device that produces a strong and ultra-thin jet of water capable of cutting through tissue. This tool precisely controls the depth of debridement to remove unwanted tissue and contaminants while preserving healthy tissue. The procedure is usually less painful than using a curette or knife. The device consists of a base unit to which the water jet knife, which is disposable equipment, is connected. It is relatively expensive and, therefore, not economically suitable for revising more minor chronic wounds.
However, in burn units, for example, where revisions on large surfaces are standard, the Versajet is often used. It is also an excellent tool to prepare a larger wound area before split-thickness skin grafts. The original Versajet device has been around for at least twenty years and has stood the test of time. However, Smith & Nephew have fine-tuned the tool. Some years ago, the Versatjet II was developed, and the model sold today is the Versajet III.
Figure 16 The Versajet Hydrosurgery system by Smith & Nephew has been around for many years and has stood the test of time. The system has undergone several modifications and improvements; the most modern model is the Versajet III (right side). The handpiece and connecting tubes are single-use and relatively expensive. Thus, only larger clinics and burn units can usually afford to use this debridement tool.
Video 5 This short video by Smith& Nephew explains shortly how Versajet Hydrosurgical debridement works. Click on the image to watch the video on YouTube—copyright: Smith & Nephew.
Ultrasonic Assisted Wound Debridement ( UAW)
Ultrasonic-assisted wound Debridement (UAW) uses the effects of cavitation to debride wounds selectively. The vibrations of the UAW instrument cause cavitation at an ultrasonic frequency of 25 kHz in an irrigation solution like saline water.
So, what exactly is cavitation? Cavitation is caused when tiny bubbles in the fluid burst, releasing energy. This energy is strong enough to remove devitalized tissue and disrupt the biofilm. The tiny bubbles arise from the ultrasonic waves produced by the instrument. Devitalized tissue and foreign bodies are removed from the wound bed, and biofilms are disrupted while trauma to the surrounding vital tissue is minimized. These effects make ultrasonic debridement highly beneficial in cleansing wounds in preparation for adjunct therapies, like using negative pressure wound therapy or in preparing skin graft recipient sites.
Figure 17 One of the leading producers of UAW debridement equipment is Söring. We are fortunate to have the Sonoca 185 model at our clinic, where it is used regularly. It is an expensive product and is only economically feasible if you have a high volume of patients with complicated ulcers. From left to right: a) stand with foot pedal, b) the ultrasonic generator, c) irrigation fluid, d) handpiece, and e) an optional silicone shield to protect from aerosols ( recommended!). Note that the handpieces can be re-sterilized. copyright: Söring
Since we have used the Sonoca 185 model from Söring for several years, what are our experiences with this type of debridement? Firstly, ultrasonic wound debridement machines are costly. To justify the purchase, you must work at a wound center with a high volume of more extensive, complicated ulcers. It's wholly unrealistic to buy this type of equipment for smaller clinics. One thing is the purchase of the ultrasonic generator, but the single-use equipment needed ( tubing from irrigation fluid to handpiece) is also expensive.
For most of our patients, we still use sharp debridement and debridement fiber cloths. But in select cases, we like to supplement with UAW debridement. These are typically patients with superficial but somewhat resistant slough where sharp debridement would be painful. Usually, UAW debridement is less painful than using a curette and slightly more painful than using debridement cloths—i.e., somewhere in between. We routinely use numbing cream or gel and leave it on the wound surface for about 20-30 minutes before starting the treatment.
One thing we really like about UAW debridement is that it not only debrides but simultaneously gives the tissues a really deep yet gentle irrigation. In our opinion, it is one of the best methods for preparing wounds for split-skin grafting or negative pressure treatment.
When caregivers use UAW debridement for the first time, they are often disappointed that it is less aggressive than they imagined. It does not just magically melt away all slough and necrosis. It usually takes multiple passes with the handpiece before superficial necrotic tissue loosens. Depending on the amount of necrosis, we will often debride for about 10- 15 minutes, using about 500ml of saline during the process. Usually, we have to stop when the patient starts to feel discomfort and remove more in the next session. Concerning how effective it is for removing necrotic tissue, we can say it is not more effective than a curette. However, the way it debrides makes the product unique- the combined high-pressure irrigation and simultaneous debridement make the wound appear cleaner than with most other methods.
Are there any downsides to using UAW? Apart from the costs? Ye One major downside is that the squirts and aerosols from the wound during the debridement make this procedure quite messy. You must cover a larger area around the wound with absorbent pads and protect yourself with a gown, facemask, and head cover. Söring sells a silicone shield to attach to the handpiece containing the squirts and aerosols. This is quite helpful ( albeit quite expensive, as it is single-use!), but after some minutes, condensation tends to form on the inside of the shield, obscuring the view. We know some clinics that started using UAW debridement but gave it up because they found it more of a hassle than a joy.
We find that the downsides weigh up for the benefits and have become fans of this debridement tool.
Note that the treatment is not without potential harm. The ultrasonic vibrations in the headpiece generate warmth if the probe is kept in the same place for more than a second! You have to keep moving the debridement handpiece continuously and use sufficient irrigation fluid running all the time to cool it down! In the start, when we had little experience with this tool, we did cause minor burns in the wound bed in a few patients!
We justify the costs ( about 100 US dollars per treatment!) because we see wounds healing faster when we use UAW debridement. In many Western countries where a visit by a homecare nurse costs about the same, the economics quickly add up. For example, Patient X has a homecare nurse visiting twice weekly to change the wound dressings. As mentioned above, a visit by a homecare nurse often costs around 100 US dollars. If your treatment reduces the healing time of the ulcer by, let's say, four weeks, then we have saved 800 US dollars in homecare expenditures, not yet counting the costs of dressing materials, etc. In other words- we can easily justify 2-3 sessions with this tool and still save much money. However, it is not that easy. Ou hospital director may say: " Wait a minute, I see your simple mathematical equation, but the costs of using homecare has nothing to do with the hospital, that is the problem of primary healthcare! Your fancy UAW debridement tool is way too expensive for our hospital!" This is where you have to put on your diplomatic hat and argue that a hospital also has socio-economic responsibilities beyond tight hospital budgets.
Video 6 A short demonstration of using the Söring UAW Sonoca 185 device for debriding wounds. Note that the video shows the previous model of the Sonoca 185. You will find many other videos about this topic on YouTube, but they require you to log in as they contain more graphic content. Copyright Jon Show, Youtube
Figure 18 There are many ultrasonic debriment units models to choose from today's market. They vary quite considerably in price. It is usually not difficult to get hold of a used unit on sites like eBay or other online re-sale markets. The model marked in red is the SonicOne OR UAW System, a good alternative to the Söring Sonicare 185 model described previously. We have tried the SonicOne OR UAW device on a conference stand and were impressed with it. It has a built-in vacuum to reduce squirts and aerosols during the treatment. We have not tried any of the other devices shown here. From left to right: a) SonicOne UAW, b) SonicOne OR UAW, c)Genera Ultrasonic system, d) Esacrom Ultrasonic, e)Infitek Ultrasonic, f)Syllable UAW
Video 7 is a short introduction to the SonicOne OR UAW system. Several videos showing live surgery with these tools are on YouTube, but due to the graphic content, you will have to sign in to view them.
Biological debridement using maggots ( MDT- Maggot Debridement Therapy)
Using medicinal maggots for debridement is hands-down one of the best methods. This is nothing new; maggot-assisted debridement of wounds has already been described in ancient times. The literature uses many terms for this treatment method. Larval debridement therapy (LDT), biosurgery, or simply maggot therapy are commonly used terms.
Only maggots from certain types of flies can be used, as some fly maggots can harm humans. Most commonly, maggots from the green bottlefly (Lucilia serrata) are used for this purpose. This type of fly is common worldwide and is easily recognized by its body's green metallic luster.
In the Western world, there are strict rules for using medicinal maggots. They have to be classified as surgical-grade fly larvae bred from sterilized eggs in a laboratory. The FDA-approved clinical indication for MDT is "debridement of non-healing necrotic skin and soft tissue wounds such as pressure ulcers, neuropathic foot ulcers, chronic leg ulcers, or non-healing traumatic or post-operative wounds."
The use of MDT is growing worldwide; in the US, there are approximately 300 centers, and about 1000 centers in the UK and Europe doing maggot therapy. Several commercial companies around the world produce medical-grade maggots for MDT. One of the world's biggest producers of medical-grade maggots is Biomonde, located in the UK and Germany. From here, sterile maggots are sent to clinics all over Europe by couriers like DHL. It is costly to produce sterile maggots, and thus, they are not cheap to buy. Unfortunately, the price will make it unrealistic for most African low-resource clinics to purchase these from companies like Biomonde. Furthermore, the logistics of getting the maggots to a rural hospital in Ghana or Lesotho, for example, would be challenging. The maggots are shipped right after hatching and are not very resistant in this state- that is, they would likely not survive the journey.
We know some university clinics in South Africa are looking into rearing their medical maggots, and we will keep you updated soon. Could you produce "sterile" medicinal maggots yourself? Well, concerning FDA regulations, that would be a clear no. However, if commercial-grade medical maggots are entirely unattainable for you, but need them to save a foot, would you consider rearing your own? If someone is raising eyebrows now, keep in mind the realistic situation in many rural, impoverished regions of Africa. If you knew that utilizing home-bred "clean enough" maggots would save that leg from amputation, you would do it. Medicinal maggots are, unfortunately, under-utilized in Africa, on a continent where they would be much needed. We will, therefore, provide you with a more detailed chapter on maggot wound debridement and how to rear your own. This chapter is in the making, and we will keep you posted when it is ready.
Figure 19 Not all fly species can be used for maggot therapy in wound care, as some species cause harm to viable tissue. Most commonly, larvae from the green bottlefly (Lucilia serrata) are used for debridement in wound care. credit: Shutterstock
Until the chapter on MDT is ready, here are a few quick facts :
-
MDT is one of the most efficient debridement methods
-
Maggots are the best biosurgeons, and they distinguish clearly between necrotic and viable tissue
-
Maggots do not harm viable tissue
-
MDT treatment is usually quite painless; sometimes, patients describe a burning sensation. However, occasionally, some patients will experience more pronounced pain. In this case, the maggots should be removed, and the wound should be irrigated with saline solution. Typically, patients who may experience more than usual pain under MDT are those whose pain was already present prior to the application of the larvae.
-
The enzymatic cocktail has strong antibacterial properties and can resolve local infection in the wound area.
-
Medicinal maggots do not have teeth—they do not bite away at necrotic tissue. Instead, they secrete a potent mixture of enzymes that dissolve dead tissue, liquefying it. The maggots feed on this liquid.
-
The maggots do not need direct contact with the necrotic tissue to dissolve it.
-
Previously, maggots were sold as " free-range." These were placed into the wound and covered with breathable fabric to deter them from escaping. Frequently, some managed to escape, which was not popular with patients or caregivers.
-
Today, most companies sell medicinal maggots in "bio-bags." These bags resemble tea bags. These bio-bags come in different sizes depending on the size of the wound. The entire bag is placed into the wound.
-
Usually, about ten maggots per square cm of wound area are needed. A 5 cm2 wound would need about 50 maggots. We often start with lower " dosages" of maggot concentrations to check if the therapy is well tolerated. It is not always a matter of " more is better."
-
In the process of liquifying necrotic tissue, the maggots produce a lot of secretion and exudate. You will have to prepare for this and may have to change the outer dressing often. The exudate containing these extremely powerful proteolytic enzymes can irritate the wound edges and cause a burning sensation. Using skin-protective barrier products around the wound edges can prevent this irritation.
-
Maggots need oxygen to survive. The wound surrounding the biobag must be covered by breathable material, such as cotton gauze.
-
Usually, the maggots are left in the wound for about three days, after which they have grown significantly and become less productive.
-
If there is much necrosis, repeated applications of maggots will be needed.
-
Not all patients will find this treatment acceptable. Never force a patient to accept treatment with maggots, as it can cause psychological discomfort. Respect cultural differences concerning this.
Figure 20 The biobags containing the tiny larvae from Biomonde come in a plastic vial with a breathable lid. The bag on the right image has been cut open for demonstration purposes. The small piece of foam in the middle of the biobag ensures that the larvae are not squeezed together under transport. Once placed into the wound, the foam ensures that the maggots get enough oxygen and do not drown in the wound's exudate. copyright: Biomonde
Figure 21 Biomonde UK has an excellent educational service about larval debridement therapy. You will find many instructional videos on their website, and we recommend you subscribe to their website for live webinars and other educational services. Click on the image above to get to their educational site. copyright: Biomonde
Figure 22 Click on the image above to read more about larval therapy from Biomonde. copyright: Biomonde
Figure 23 For further reading about wound debridement, we recommend this document from the Journal of Wound Care. Click the image above to get to the document. copyright: JWC
