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ROLE OF DEBRIDEMENT
Debridement is the removal of necrotic, contaminated, or foreign material from a wound or from areas adjacent to the wound. Although data from controlled trials are limited, it is considered a key component of wound management due to its purported ability to induce acute healing and reduce microorganisms. Five types of debridement exist: surgical, mechanical, autolytic, enzymatic, and biologic. Although surgical debridement is often the fastest and most direct way of removing unhealthy tissue, it may not be the method of choice for all patients. Factors such as the frequent need for analgesics, possible bleeding, the extent of non-viable tissue, patient preferences, and the practitionerโs level of expertise need to be considered. An example of mechanical debridement is the wet-to-dry dressing that is employed for wounds with significant necrotic tissue, but it does not distinguish between viable and non-viable tissue.
In autolytic debridement, occlusive dressings provide a moist wound environment which promotes the lytic activity of enzymes present in accumulated wound fluid. This assists in the clearance of residual debris during early wound healing. Enzymatic (chemical) debridement involves the topical application of an enzymatic agent and this can be used to supplement autolytic debridement. Currently, one agent is FDA-approved: collagenase (Santylยฎ) ointment. It assists in the removal of devitalized tissue and aids in granulation tissue formation and re-epithelialization.
Biologic debridement employs fly larvae (maggots) and has been used for centuries to debride chronic ulcers. Nowadays, the most commonly used maggots are those of the green bottle fly, Lucilia sericata. Maggots digest necrotic tissue via collagenases and trypsin-like enzymes, thereby exposing healthy tissue. They also have antimicrobial effects, including secretion of antibacterial compounds (e.g. phenylacetic acid, phenylacetaldehyde) in addition to ingestion and subsequent killing of Gram-positive bacteria (including MRSA) and, to a lesser extent, Gram-negative bacteria. In a clinical trial of 267 patients with leg ulcers, larval therapy led to faster debridement than hydrogel therapy, but larval therapy has not been shown to improve healing rates or decrease bacterial load.