Atlanta — "Wound healing should ideally result in complete and sustained recovery of intact tissue structure and function, but dermal ulcer wounds don't always heal as expected," says Michael G. Franz, M.D., assistant professor of surgery at the University of Michigan. Dr. Franz discussed obstacles to wound healing in a one-day symposium on "Basics of Wound Care" presented at the 15th annual meeting of the Wound Healing Society.
"Biological limitations in the wound healing process, intrinsic impediments to healing and extrinsic obstacles such as trauma can all lead to failure, resulting in a chronic dermal ulcer wound," Dr. Franz says.
Phases of wound healingNormally the wound healing process goes through a lag phase, a proliferative stage and a remodeling stage. The lag phase is characterized by hemostasis; platelet aggregation; infiltration of inflammatory cells, such as neutrophils and monocytes; and release of cytokines. In the next stage, fibroblasts proliferate, myofibroblasts appear and angiogenesis occurs. Granulation tissue is deposited as the wound heals, and re-epithelialization, wound contraction and scar formation take place. The collagen fiber bundle undergoes remodeling as the final step in wound healing. Chronic wounds are characterized by their failure to progress through the stages of wound healing in a timely manner.
Obstacles to wound healing
"Obstacles to wound healing impair progression of cellular and molecular components of tissue repair and prevent the complete and sustained recovery of normal anatomic structure and function," Dr. Franz says. "Often the obstacles are reversible."
Obstacles can be systemic or local. Systemic obstacles to wound healing include malnutrition, underlying disease such as diabetes, pain and steroid use, among others. Local obstacles include wound infection or necrosis, tissue hypo-perfusion, trauma to the wound, desiccation or irradiation of the tissue, presence of foreign bodies and edema. Neoplasms (Marjolin's ulcer) may arise in chronic dermal wounds or burns; in such cases, biopsy is critical before wound healing can take place.
"The mechanisms of delayed wound healing help explain the categories of risk factors observed clinically," Dr. Franz says.
"The goal in wound therapy is to shift the components of wound healing back into timely repair," he says. "Infection control, maintaining a moist wound environment and pain management are essential in achieving this goal. Surgical procedures such as debridement or revascularization may be necessary, and therapies such as compression therapy, treatment with growth factors and off-loading may also be appropriate."
Disclosure: Dr. Franz reports no conflicts of interest.