woundhealing

Wound healing refers to the physiological process by which tissue repairs after injury. It aims to restore structural integrity and function through coordinated cellular responses and remodeling.

The process is traditionally described in four overlapping phases: hemostasis and coagulation to stop bleeding; inflammation to clear debris and pathogens; proliferation to re-epithelialize and form granulation tissue; and remodeling, during which collagen is reorganized and tissue strength increases over weeks to months.

The key players include platelets, neutrophils, macrophages, fibroblasts, and endothelial cells. Platelets release growth factors that recruit inflammatory cells and stimulate angiogenesis. Macrophages orchestrate debris clearance and drive the transition to the proliferative phase. Fibroblasts synthesize collagen and other extracellular matrix, while endothelial cells form new blood vessels.

Wound healing outcomes depend on wound apposition. Primary intention occurs when edges are closed with minimal scar. Secondary intention involves healing from the base with granulation tissue and contraction, typically leaves a larger scar. Tertiary intention is delayed primary closure after contamination or infection.

Healing is influenced by systemic factors such as age, nutrition, diabetes, immunosuppression, and smoking; and local factors including infection, tissue perfusion, necrotic tissue, moisture, and mechanical stress. Certain medications, like corticosteroids and some chemotherapeutics, may impair healing.

Complications include infection, wound dehiscence, chronic non-healing wounds, fistula formation, and abnormal scarring (hypertrophic scars and keloids).