Debridement is the medical removal of a patient’s dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue. Removal may be surgical, mechanical, chemical, autolytic (self-digestion), and by maggot therapy, where certain species of live maggots selectively eat only necrotic tissue.
In oral hygiene and dentistry, debridement refers to the removal of plaque and calculus that have accumulated on the teeth. Debridement in this case may be performed using ultrasonic instruments, which fracture the calculus, thereby facilitating its removal, as well as hand tools, including periodontal scaler and curettes, or through the use of chemicals such as hydrogen peroxide.
An open wound or ulcer can not be properly evaluated until the dead tissue or foreign matter is removed. Wounds that contain necrotic and ischemic (low oxygen content) tissue take longer to close and heal. This is because necrotic tissue provides an ideal growth medium for bacteria, especially for Bacteroides spp. and Clostridium perfringens that causes the gas gangrene so feared in military medical practice. Though a wound may not necessarily be infected, the bacteria can cause inflammation and strain the body’s ability to fight infection. Debridement is also used to treat pockets of pus called abscesses. Abscesses can develop into a general infection that may invade the bloodstream (sepsis) and lead to amputation and even death. Burned tissue or tissue exposed to corrosive substances tends to form a hard black crust, called an eschar, while deeper tissue remains moist and white, yellow and soft, or flimsy and inflamed. Eschars may also require debridement to promote healing.
Major debridement techniques
Surgical debridement (also known as sharp debridement) uses a scalpel, scissors, or other instrument to cut necrotic tissue from a wound. It is the quickest and most efficient method of debridement. It is the preferred method if there is rapidly developing inflammation of the body’s connective tissues (cellulitis) or a more generalized infection (sepsis) that has entered the bloodstream. The physician starts by flushing the area with a saline (salt water) solution, and then applies a topical anesthetic or antalgic gel to the edges of the wound to minimize pain. Using forceps to grip the dead tissue, the physician cuts it away bit by bit with a scalpel or scissors. Sometimes it is necessary to leave some dead tissue behind rather than disturb living tissue. The physician may repeat the process again at another session.
In mechanical debridement, a saline-moistened dressing is allowed to dry overnight and adhere to the dead tissue. When the dressing is removed, the dead tissue is pulled away too. This process is one of the oldest methods of debridement. It can be very painful because the dressing can adhere to living as well as nonliving tissue. Because mechanical debridement cannot select between good and bad tissue, it is an unacceptable debridement method for clean wounds where a new layer of healing cells is already developing.
Chemical or enzymatic debridement
Chemical debridement makes use of certain enzymes and other compounds to dissolve necrotic tissue. It is more selective than mechanical debridement. In fact, the body makes its own enzyme, collagenase, to break down collagen, one of the major building blocks of skin. A pharmaceutical version of collagenase is available and is highly effective as a debridement agent. As with other debridement techniques, the area first is flushed with saline. Any crust of dead tissue is etched in a crosshatched pattern to allow the enzyme to penetrate. A topical antibiotic is also applied to prevent introducing infection into the bloodstream. A moist dressing is then placed over the wound.
Autolytic debridement takes advantage of the body’s own ability to dissolve dead tissue. The key to the technique is keeping the wound moist, which can be accomplished with a variety of dressings. These dressings help to trap wound fluid that contains growth factors, enzymes, and immune cells that promote wound healing. Autolytic debridement is more selective than any other debridement method, but it also takes the longest to work. It is inappropriate for wounds that have become infected.
Maggot therapy is a form of biological debridement known since antiquity. The larvae of Lucilia sericata (greenbottle fly) are applied to the wound as these organisms can digest necrotic tissue and pathogenic bacteria. The method is rapid and selective, although patients are usually reluctant to submit to the procedure.
The physician or nurse will begin by assessing the need for debridement. The wound will be examined, frequently by inserting a gloved finger into the wound to estimate the depth of dead tissue and evaluate whether it lies close to other organs, bone, or important body features. The assessment addresses the following points:
- the nature of the necrotic or ischemic tissue and the best debridement procedure to follow
- the risk of spreading infection and the use of antibiotics
- the presence of underlying medical conditions causing the wound
- the extent of ischemia in the wound tissues
- the location of the wound in the body
- the type of pain management to be used during the procedure
Before surgical or mechanical debridement, the area may be flushed with a saline solution, and an antalgic cream or injection may be applied. If the antalgic cream is used, it is usually applied over the exposed area some 90 minutes before the procedure.
After surgical debridement, the wound is usually packed with a dry dressing for a day to control bleeding. Afterward, moist dressings are applied to promote wound healing. Moist dressings are also used after mechanical, chemical, and autolytic debridement. Many factors contribute to wound healing, which frequently can take considerable time. Debridement may need to be repeated.
It is possible that underlying tendons, blood vessels or other structures may be damaged during the examination of the wound and during surgical debridement. Surface bacteria may also be introduced deeper into the body, causing infection.
Removal of dead tissue from pressure ulcers and other wounds speeds healing. Although these procedures cause some pain, they are generally well tolerated by patients and can be managed more aggressively. It is not uncommon to debride a wound again in a subsequent session.
Not all wounds need debridement. Sometimes it is better to leave a hardened crust of dead tissue (eschar), than to remove it and create an open wound, particularly if the crust is stable and the wound is not inflamed. Before performing debridement, the physician will take a medical history with attention to factors that might complicate healing, such as medications being taken and smoking. The physician will also note the cause of the wound and the ways it has been treated. Some ulcers and other wounds occur in places where blood flow is impaired, for example, the foot ulcers that can accompany diabetes mellitus. In such cases, the physician or nurse may decide not to debride the wound because blood flow may be insufficient for proper healing.
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