Chronic wounds

Abstract

Chronic wounds are characterized by their inability to heal within an expected time frame and have emerged as an increasingly important clinical problem over the past several decades, owing to their increasing incidence and greater recognition of associated morbidity and socio-economic burden. Even up to a few years ago, the management of chronic wounds relied on standards of care that were outdated. However, the approach to these chronic conditions has improved, with better prevention, diagnosis and treatment. Such improvements are due to major advances in understanding of cellular and molecular aspects of basic science, in innovative and technological breakthroughs in treatment modalities from biomedical engineering, and in our ability to conduct well-controlled and reliable clinical research. The evidence-based approaches resulting from these advances have become the new standard of care. At the same time, these improvements are tempered by the recognition that persistent gaps exist in scientific knowledge of impaired healing and the ability of clinicians to reduce morbidity, loss of limb and mortality. Therefore, taking stock of what is known and what is needed to improve understanding of chronic wounds and their associated failure to heal is crucial to ensuring better treatments and outcomes.

Figure 1:

Representative clinical photos of typical chronic wounds. A) Diabetic ulceration due to both neuropathy and arterial insufficiency. The forefoot has been previously amputated; B) Venous ulcer with surrounding lipodermatosclerosis on the medial aspect of the ankles; C) Deep decubitus (pressure) ulcer in the sacral area; D) Neuropathic diabetic ulcer on the sole in a diabetic patient with Charcot foot; E) Extensive ulceration of the lower leg due to combined venous and lymphatic disease. The deep red granulation tissue is not normal and may signify bacterial colonization. The edges of the wound (surrounded by indurated and fibrotic skin) and the island of skin in the wound be are unable to migrate onto the wound bed.

Figure 2.

Diagrammatic representation of the wound healing process in acute wound healing and in chronic wounds. Unlike the linear relationship of the recognized phases of normal wound healing (A: left panel), chronic wounds (B: right panel) are characterized by a process whereby the different phases take place at random and with no defined timeframe. Some parts of the wound are in different phases of healing.

Figure 3:

Schematic representation of the inflammatory component of wound healing process in normal healing and chronic wounds. After the inflammatory phase, normal healing wounds can transition to the proliferative phase of wound healing which is hallmarked by the shift of the responses of immune cells to anti-inflammatory and proliferative to allow tissue repair (right panel). Chronic wounds are instead characterized by a stagnant and deregulated phase which fails to quench local inflammatory responses and does not progress to tissue repair (left panel).

Figure 4:

Representation of key component that characterize the path to impaired healing in chronic wounds.

Figure 5:

General algorithm for the evaluation, diagnosis, and treatment strategies for chronic wounds.

Figure 6:

Representation of some critical clinical components of wound bed preparation, with a scoring system (wound bed score or WBS) that may be useful for assessment, follow up, and for decision making in the use of therapeutic agents.