Debridement is the removal of necrotic tissue from a wound. Generally, the presence of necrotic or dead tissue is seen as a delaying factor in pressure ulcer healing, preventing the formation of healthy granulation tissue and a good environment to harbor more bacteria, thereby increasing the risk of further sepsis.
Debridement is the removal of necrotic tissue, foreign debris, bacterial growth, callus, wound edge, and wound bed tissue from chronic wounds in order to stimulate the wound healing process. Stimulation of wound healing mediated by debridement is thought to occur by the conversion of a chronic non-healing wound environment to an acute healing environment through the removal of cells that are not responsive to endogenous healing stimuli. Debridement is used commonly in standard wound treatment of diabetic foot ulcers (DFUs). Methods of debridement include surgery (sharp debridement), chemical debridement (antiseptics, polysaccharide beads, pastes), autolytic (hydrogels, hydrocolloids and transparent films), biosurgery (maggots), mechanical (hydrodebridement), and biochemical debridement (enzyme preparations).
The concept of preparing the wound bed to promote reepithelialization of chronic wounds has been applied to wound management for more than a decade. The 4 general steps to follow for better preparation are compassed in the acronym DIME.[rx][rx][rx][rx][rx]
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D: Debridement of nonviable tissue within the Wound.
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I: Management of Inflammation and Infection
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M: Moisture control
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E: Environmental and Epithelialization assessment
The DIME approach to chronic wound management is a global concept approach from which a more detailed pathway can be initiated to bring about wound resolution.
The primary goal of debridement is to remove all the devitalized tissue from the wound bed to promote wound healing. Debridement is also used for the removal of biofilm, bioburden along with senescent cells, and it is suggested to be performed at each encounter.[rx][rx][rx]
Types of Debridement
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Hydrosurgical debridement – (e.g., water jet and high powered parallel water jet tools) is a new and useful tool in surgical debridement. Hydrosurgical debridement works by forcing a narrow stream of saline under high pressure out of a nozzle, using the Venturi effect, to remove the debrided tissue. It successfully clears bacteria from the wound bed, and this technique does not create bacterial seeding deeper into the wound bed.[rx] Pressure settings can be adjusted to gently debride a superficial wound and remove pseudoeschar to debride deep partial-thickness burns aggressively. This process also effectively and precisely debrides fascia and tendon but does not affect bone or hard eschar. Eschars that are deep, hard, dry, or leathery are not easily debrided and require multiple passes as well as higher pressure settings.[rx][rx] Proponents of this technique advocate that this does not necessitate a big or intricate surgical instrument tray, which allows for quicker set-up and operating room turn over. The selectivity of hydrosurgical debridement saves money in the operating room. It decreases the number of operative take-backs for further debridement due to the specificity and efficiency of the debridements. The tool is small enough to debride hard to reach locations and obtain a better contour of the tissue to allow superficial to deep partial-thickness burns to be successfully excised more efficiently. The effectiveness of hydrosurgical debridement to produce healthy bleeding wound beds is comparable to cold knife and brush techniques but with better speed and precision. The advantages of hydrosurgical debridement are the ease in learning the technique and the reduction of total debridements, which lower operative costs. However, as previously stated, full-thickness burns will still require cold knife excision.
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Autolytic/Enzymatic debridement – involves the use of proteolytic enzymes and agents that digest the burned and dead tissue. This process is limited in its use because it has a slower healing time and results in significant pain with dressing changes that require appropriate analgesia. The necrotic tissue is slowly debrided and can promote an invasive infection or even produce a septic inflammatory response.[rx] Debridement with collagenase and papain/urea agents has shown success, but they are time and labor-intensive and not ideal in extensive TBSA burns.[rx] Bromelain-based agents have some utility as they are highly specific for burn eschar. They do not penetrate the intact dermis and avoid breakdown of healthy, viable tissue. Compared to surgical debridement, these agents have been found to decrease the total number of debridements, time to healing, and the need for autografting. Enzymatic debridement with bromelain-based agents allows for faster re-epithelialization and selective debridement down to bleeding, viable tissue. Another potential advantage for its use is the avoidance of escharotomy to avoid compartment syndrome caused by circumferential burns found in one study.[11] Financially, these topical debriding agents allow for a reduction in overall cost when used for burns less than 15% TBSA. At over 15% TBSA, the savings were no different than other types of debridement. Some of the disadvantages of using enzymatic debridement include an associated local redness to the treated area, which can be a cosmetic concern to some patients. There is also increased pain with the application and removal of the enzymatic agents when done bedside with no anesthesia.[rx]
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Mechanical debridement – can be utilized with frequent moist to dry dressing changes. This process involves placing a moist dressing over the affected area and then removing the dressing when it is dry. This technique removes the dead tissue adherent to the dressing but causes significant pain and can be nonspecific in removing surrounding healthy tissue.[rx]
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Sterile maggots – can be used in biologic debridement as they will only consume the necrotic wound tissue. This technique is successful and an effective strategy; however, there is hesitancy and apprehension from patients and healthcare staff when using this technique that limits real-world applications.[rx]
Anatomy and Physiology
The skin’s 2 main layers are the epidermis and the dermis. The epidermis is composed up of closely packed epithelial cells, and the dermis is composed of dense, irregular connective tissue where the blood vessels, hair follicles, sweat glands, and other structures are housed. The hypodermis lies beneath the dermis. Its composition is mostly loose connective and fatty tissues. Muscle, tendons, ligaments, bone, and cartilage are all under the hypodermis.
The epidermis is composed of keratinized, stratified, squamous epithelium. The dermis contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands.
Indications of Debridement
In general, the indication for debridement is the removal of devitalized tissue such as necrotic tissue, slough, bioburden, biofilm, and apoptotic cells.
Debridement is recognized as a major component of wound management to prepare the wound bed for reepithelialization. Devitalized tissue, in general, and necrotic tissue, in particular, serve as the source of nutrients for bacteria. Devitalized tissue also acts as a physical barrier for reepithelialization, preventing applied topical compounds to make direct contact with the wound bed to provide their beneficial properties. Necrotic tissue also prevents angiogenesis, granulation tissue formation, epidermal resurfacing, and normal extracellular matrix (ECM) formation. Finally, the presence of necrotic tissue may prevent the clinician from making an accurate assessment of the extent and severity of the wound, even masking possible underlying infections.[rx][rx][rx]
Schiffman et al. include the following as common indications for sharp surgical debridement.
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Removal of the source of sepsis, mainly necrotic tissue
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Removal of local infection to decrease bacterial burden, to reduce the probability of resistance from antibiotic treatment, and to obtain accurate cultures
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Collection of deep cultures taken after debridement from the tissue left behind to evaluate persistent infection and requirements for systemic antibiotic treatment
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Stimulation of the wound bed to support healing and to prepare for a skin graft or flap
Contraindications of Debridement
Contraindication of wound debridement, in general, may be applied to dry and intact eschars with no clinical evidence of underlying infection such as with an unstageable pressure ulcer with an intact eschar at the sacrum or buttock or heel.
Other contraindications pertain to each particular method of debridement.
Technique of Debridement
Several types of debridements can achieve the removal of devitalized tissue. These include surgical debridement, biological debridement, enzymatic debridements, and autolytic debridement.
Autolytic Debridement
This is the most conservative type of debridement. This type of debridement is a natural process by which endogenous phagocytic cells and proteolytic enzymes break down necrotic tissue. It is a highly selective process whereby only necrotic tissue will be affected in the debridement.
It is indicated for noninfected wounds. It may also be used as adjunctive therapy in infected wounds. It can be used with other debridement techniques such as mechanical debridement in the case of infected wounds.
It requires a moist environment and a functional immune system. The use of moisture-retentive dressings can enhance it. This type of debridement induces the softening of the necrotic tissue and eventual separation from the wound bed.
The effectiveness of this type of debridement is mandated by the amount of devitalized tissue to be removed as well as the actual wound size.
Autolytic debridement will take a few days. If a significant decrease in necrotic tissue is not seen in 1 or 2 days, a different method of debridement should be considered.
Biological Debridement
Biological debridement, also known as larval therapy, uses sterile larvae of the Lucilia sericata species of the green bottle fly. It is an effective mode of debridement, particularly appropriate in large wounds where a painless removal of necrotic tissue is needed. The mechanism of action of mega therapy/debridement consists mainly of the release of proteolytic enzymes containing secretions and excretions that dissolve necrotic tissue from the wound bed. Other modes of action contributing to the overall result of larval therapy are:
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Bacteriocidal, as the larvae ingest and digest bacteria
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Inhibiting bacterial growth by producing in releasing ammonia into the wound bed which increases the wound pH
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Breakdown of existing biofilm at the wound bed and inhibition of new biofilm growth
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Direct ingestion of necrotic tissue
Maggots can be applied to the wound bed. They can be enclosed in a biological bag or are free-range.
Studies have shown that free-range maggots can debride a wound at least twice as fast as bag-pain maggots. Comparison studies of either free-range maggots treatment versus bio bag contained maggots versus hydrogel autolytic debridement shows days to complete debridement to be 14 versus 28 versus 72 days respectively.
Contraindications to biological debridement are an abdominal wound contiguous with the intraperitoneal cavity, pyoderma gangrenosum in patients with immunosuppression therapy, and wounds in proximity to areas afflicted by septic arthritis.
Enzymatic Debridement
This is a selective method for debridement of necrotic tissue using an exogenous proteolytic enzyme, collagenase, to debride Clostridium bacteria. Collagenase digests the collagen in the necrotic tissue allowing it to detach.
Enzymatic debridement is a slow method of the debridement as from hair to mechanical and sharp debridement.
Collagenase and moisture-retentive dressings can work in synergy enhancing the debridement.
Enzymatic debridement is not recommended for an advanced process, or in patients with known sensitivity to the product’s ingredients.
A relative contraindication of enzymatic debridement is its use in heavily infected wounds. Furthermore, collagenase should not be used in conjunction with silver-based products or with Dakin solution.
Surgical Debridement with Sharp Instruments
This is a type of debridement where devitalized tissue (slough, necrotic, or eschar) in the presence of underlying infection is removed using sharp instruments such as a scalpel, Metzenbaum, curettes, among others. This can be done bedside, in the office or wound care center, or in the operating room depending on the adequacy of anesthesia and the ability to control perioperative complications like bleeding. The healthcare professional should be skilled and trained and qualified and licensed to provide surgical treatment.
Sharp-instrument debridement can be combined with all the other methods of debridement during the perioperative period.
Disadvantages of surgical debridement include adverse events from the debridement itself, for example, bleeding and possible general complications from the anesthesia.
Contraindications for surgical debridement in the operating room would have to take into account the particular surgical risk stratification of the patient. Sharp surgical debridement is contraindicated in patients with an intact eschar and no clinical evidence of an underlying infection because in these cases, the intact eschar functions as a biological covering for the underlying skin defect. This is usually seen in unstageable pressure injuries at the sacrum or buttocks or heels with intact and/or dry eschars.
Mechanical Debridement
Mechanical debridement is a nonselective type of debridement, meaning that it will remove both devitalized tissue and debris as well as viable tissue. It is usually carried using mechanical force: wet-to-dry, pulsatile lavage, or wound irrigation.
It is indicated for both acute and chronic wounds with moderate to large amounts of necrotic tissue, regardless of the presence of an active infection.
The contraindications include, depending on the modality of mechanical debridement used, the presence of granulation tissue in a higher amount than the devitalized tissue, inability to control pain, patients with poor perfusion, and an intact eschar with no gross clinical evidence of an underlying infection.
Complications
Depending on the type of debridement chosen, complications range from local irritation to major bleeding.
Surgical debridement and mechanical debridement will have a higher risk for bleeding, along with peri-procedural pain.
Surgical debridement done in the operating room must account for morbidity and mortality due to the anesthesia used. A study by J. Shiffman et al. has shown operative mortality to be 2% with long-term mortality, and as high as 68% following debridement.
References