[Surgical biology of wound healing]

Wound healing is a dynamic, interactive process involving soluble mediators, blood cells, extracellular matrix, and parenchymal cells. It has three phases-inflammation, tissue formation, and tissue remodelling-that overlap in time. Tissue remodelling of an acute wound is closely controlled by regulatory mechanisms which maintain a delicate balance between synthesis and degradation, leading to normal healing. In chronic wounds (diabetic foot, venous ulcer, pressure sore), the healing process is disturbed by various factors which prolong the inflammatory phase, creating a cascade of tissue responses which perpetuate a "non-healing" state. Among those factors we recognize tissue necrosis, infection, tissue hypoxia, exsudates with excess of inflammatory cytokines. The local treatment of chronic wounds with modern dressings, although efficacious, is too slow and too conservative. By transforming a chronic wound into an acute, the surgeon not only remove those disturbing factors but re-establishes the dynamic process of a normal wound healing.