There is significant debate, controversy, and confusion about the definition of wound healing, especially in chronic wounds. Over the years, I have reviewed numerous papers, presentations, and research protocols and the same questions keep coming up: When is a wound healed? What are the primary, intermediate, and final end points that indicate wound healing? 1
The taxonomy of these answers varies. The most common clinical and practical answer is that a wound is healed when it achieves "complete closure." If we accept this as true, it is logical to use complete closure as the end point of wound healing.
But would we be jumping the gun? Is a wound really functional at complete closure, meaning can the patient bear weight on the closed wound to use the subjacent body part or tissues? Will the wound remain closed, or is it subject to recurrence?
Through all of this confusion, one thing is clear to me: There are a lot more questions than answers.
An Imprecise Language
Part of the problem can be attributed to the taxonomy of discourse in the field of wound care. The language we speak as wound care practitioners is diverse and imprecise, as evidenced by constantly evolving definitions of the various stages of wound healing and numerous documentation tools used to capture the sensitive and specific measurements of wound healing.
I also believe that the definitions of wound healing and a healed wound vary according to whom is asked the question. End points of healing for research protocols, clinical case reports and other studies, and the patients who must function during and after wound healing may depend on the goals and expectations of the person or persons involved.
Only the Beginning
From a clinical/functional standpoint, complete closure of the wound is only the beginning of functional wound healing. Although others may see closure as the end of the story, I think it is really the beginning of the second chapter of the healing process. The final chapter is the long-term functional outcome; in other words, whether the patient's function is preserved and, moreover, whether the wound has recurred. 2
To me, closure is cicatrix, meaning the gradual accumulation of dense collagen fibers in a wound. It is the near-final stage in wound healing, and it is associated with scar formation.
When a wound heals, it is replaced with a scar. As a complex organ, the skin cannot simply regenerate like fat, connective tissue, and the epithelium. Instead, it must heal by a different process, namely formation of a predominantly fibrous tissue (a scar). 3 This final stage of wound healing may last up to 2 years, and the result will never be as strong as the original tissue.
A Complicated Story
The whole story is much more complicated, of course, as eloquently described by Ferrell. 4 He noted that healing of a pressure ulcer involves an intricate series of cellular and molecular events that lead to repair and restoration of skin integrity and function. 4 In addition, he pointed out that although complete closure is an important end point for wound healing, measuring it may not be practical in most care settings. 4
What we are left with, then, is assessment of only partial wound healing, characterized by measurement of parameters such as changes in wound size over time. 4 Ferrell underscored the lack of consensus on the best way to measure wound healing, and noted that because of this, few research papers have documented healing rates. 4
The search for an answer to the question of when a wound is really healed continues. Currently, the National Pressure Ulcer Advisory Panel, of which I am a member, is examining the complex issues related to primary end points in the healing of pressure ulcers, as well as the appropriate tools to measure outcomes. I look forward to sharing the results of this work in future issues.
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