Basic principles of wound healing
- David G Armstrong, DPM, MD, PhD
David G Armstrong, DPM, MD, PhD
- Professor of Surgery
- Director, Southern Arizona Limb Salvage Alliance (SALSA)
- University of Arizona College of Medicine
- Andrew J Meyr, DPM
Andrew J Meyr, DPM
- Clinical Associate Professor
- Temple University School of Podiatric Medicine
- Section Editors
- Russell S Berman, MD
Russell S Berman, MD
- Section Editor — Skin and Soft Tissue Surgery
- Chief of Surgical Oncology
- New York University Langone Medical Center
- John F Eidt, MD
John F Eidt, MD
- Section Editor — Vascular and Endovascular Surgery
- Professor of Surgery, Texas A&M Health Science Center
- Vice Chair of Vascular Surgical Services, Baylor Heart and Vascular Hospital at Dallas
- Joseph L Mills, Sr, MD
Joseph L Mills, Sr, MD
- Section Editor — Vascular and Endovascular Surgery
- Professor and Chief
- Division of Vascular Surgery and Endovascular Therapy
- Baylor College of Medicine
A wound is a disruption of the normal structure and function of the skin and underlying soft tissue . Wounds may be caused by a variety of mechanisms, including acute traumatic injury to the skin (abrasion, puncture, crush, burns, gunshot, animal bite, surgery) and other etiologies that cause initially intact skin to break down. Any mechanism that decreases blood flow in the skin for a prolonged period of time has the potential to cause ischemic breakdown of the skin. Skin perfusion may be impaired due to proximal arterial obstruction (eg, peripheral artery disease), vascular compression (eg, hematoma, immobility causing focal pressure), or microvascular occlusion or thrombosis (eg, vasculitis, cholesterol crystals).
Wound classification and the basic principles of wound healing are reviewed here. The factors responsible for impaired wound healing and wound complications, as well as the clinical assessment and management of wounds, are reviewed elsewhere. (See "Risk factors for impaired wound healing and wound complications" and "Clinical assessment of wounds" and "Basic principles of wound management".)
WOUND ETIOLOGY AND CLASSIFICATION
Wounds may arise through traumatic injury (including surgery) or from the breakdown of previously intact skin and are generally classified as acute or chronic.
Acute wounds — Acute wounds usually have an easily identifiable mechanism of injury with skin integrity disrupted, typically due to some form of trauma. Acute traumatic skin disruption can result from blunt or penetrating mechanisms with an array of wound sizes, depths, and locations. Simple or complicated lacerations, burns, or significant tissue defects may result, each requiring individualized management and care. (See "Basic principles of wound management", section on 'Acute wounds'.)
Surgical wounds are a controlled form of acute wound that is created in the operating room environment. Surgical wounds are classified according to the degree of bacterial load or contamination of the surgical wound and are used to predict the risk of surgical wound infection that can impact wound healing. The four categories are clean, clean-contaminated, contaminated, and dirty. The majority of clean and clean-contaminated wounds are closed primarily at the completion of the surgery; contaminated and dirty wounds as well as surgical wounds requiring removal of staples or sutures due to postoperative wound infection are left open and require wound care. The classification of surgical wounds is presented in more detail elsewhere. (See "Risk factors for impaired wound healing and wound complications", section on 'Surgical wound classification'.)
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