Complications of wound healing

Abstract

Wound healing is an organized, four-phased system involving hemostasis, inflammation, proliferation and maturation. However this process is far from simple. It involves a huge orchestration of cells and biochemical molecules in an environment of constantly changing signaling processes, temporally and spatially. A variety of physiological events and environmental agents can divert this healing cascade, alter the wound bed environment and stall healing. The pathology of a non-healing wound is highly complex and differs to a great extent from an acute wound. The resident cells are phenotypically different, senescent and resist apoptosis. The matrix becomes corrupt and shows poor response to growth factors. The growth factors may be inadequately synthesized, trapped or degraded rapidly and may have low receptor population or insensitive receptors. The inflammatory phase remains prolonged and a dynamic process of matrix degradation with attempts to repair exists in the wound environment. The failure to heal may result from various insults like biofilm formation and microbial invasion, defective signaling processes, genetically defective enzymes and wound metabolism, repeated trauma, ischemia, edema, venous hypertension and effect of mechanical forces including pressure. The corrupt matrix leads to poor migration of keratinocytes and epithelization is also delayed. A number of drugs particularly anticancer drugs may also lead to chronicity. Wound bed preparation remains the gold standard of therapy in these indolent cases. A good wound bed preparation may involve enzymatic and surgical debridement, resident fibroblast stimulation and stimulation of growth factor release, addition of extraneous growth factors to the wound, deployment of bioengineered extracellular matrix, collagen and alginates, cultured keratinocyte suspension and even bioengineered dermal preparation in any combination. Stem cell therapy holds promise. The results are encouraging although much work is yet to be done to achieve the best outcome. It should be kept in mind that any attempt in helping a chronic wound to heal should take the patient in consideration as a whole and not a leave narrow focus on the wound only.