Remember back to high school when you or one of your fellow athletes fell on the cinder track? Your coach probably got out the wire brush to clean your wound or just said “rub a little mud on it!” Mercifully, our approach to wound healing has significantly changed since then. We no longer leave wounds open to air, let them scab over or soak most wounds with cytotoxic solutions such as Cholrox.
Luckily, most simple wounds heal despite what we do to them. Problem healing wounds, on the other hand, are wounds that don't heal in an expected time frame. Wounds have defined stages of healing: hemostasis, inflammation, proliferation and remodeling. Any breakdown in the process after hemostasis can change an acute wound into a chronic wound. Comorbidities such as diabetes mellitus, cancer, peripheral neuropathy, peripheral arterial disease, venous edema, malnutrition, anemia, immunocompromised state, chronic immunosuppression and infection all can change a wound from simple to complicated. To heal these complicated wounds, it is paramount to understand and control the factors that are slowing or stopping the healing process.
The first step in the approach to wound healing begins with a thorough assessment. This assessment includes: size and depth, presence of infection, necrotic tissue, granulation tissue, presence of protective sensation and the condition of the periwound. Impediments to healing are then assessed. These include hypoxia/ischemia, unrelieved pressure, infection (cellulitis, abscess or underlying osteomyelitis), venous edema, moisture imbalance, and advanced age. Other factors which should be controlled or stabilized include blood glucose levels, autoimmune diseases, malignancy, malnutrition, radiation damage and immunosuppression.
Proper moisture balance is important for wounds to heal. Hydrocolloids, occlusive dressings or hydrogels accomplish this. New research supports keeping wounds moist with the patient's own sera which contains healing factors. Heavily exudating wounds, however, require frequent dressing changes to avoid maceration. Remembering the medical school mantra, "If it is wet you dry it and if it is dry you wet it," still serves well in directing wound care.
There are a myriad of wound care products available. They are designed to promote a proper moisture balance, provide protection, reduce bioburden, and inhibit or kill microbes, remove necrotic tissue, and provide missing healing factors. Popular dressings include silver dressings, collagen dressings, cadexomer iodine preparations, porcine-derived acellular small intestine submucosa, and active Leptospermum Honey dressings. Regranex, a recombinant human platelet derived growth factor, had been used but now has a recent black box warning limiting its use. The only enzymatic debrider currently on the market is collagenase. NPWT (e.g. Wound V.A.C.) has been a revolutionary way of treating wounds and expedites healing times.
Treating wounds for infection is important. Evidence of increased wound breakdown, increased pain, warmth, purulent drainage and fever signifies infection and requires antibiotic treatment. Debridement and antimicrobial dressings are usually required to decrease the wound bioburden (bacterial containing debris in the wound which slows healing).
Lower extremity venous edema must be controlled. These patients present with ulcers, cellulitis, and dermatitis. The initial treatment of venous stasis disease is compression to manage the edema and promote healing. Correction of venous vascular pathology can resolve many of the sequelae. Newer office techniques with guided ultrasound now allow vascular surgeons to ablate local bridging vein pathology in their office.
For many wounds, a major impediment to healing is hypoxia or ischemia. After a thorough history, the physician should check for the presence or absence of pulses. The integumetary should be examined for hair loss, fissuring, loss of subcutaneous tissue, color/temperature changes, and delayed capillary refill. Doppler evaluation can assess macrovascular flow. Transcutaneous oximetry monitoring (TCOM) measures the oxygen in the small capillaries of the skin and can assess microvascular flow. Revascularization through open bypass or percutaneous vascular procedures (e.g. Silverhawk/laser, angioplasty and stenting) can improve blood flow in not only the iliac and femoral arteries, but also the smaller infrapopliteal arteries. Strict off-loading to allow healing is essential for neuropathic foot ulcers and other pressure ulcers.
Some hypoxic chronic refractory wounds require adjunctive hyperbaric oxygen (HBO) treatments for healing. These wounds include diabetic foot wounds of Wagner grade III or higher, soft tissue radiation necrosis wounds, necrotizing soft tissue infections, gas gangrene and compromised skin grafts/flaps. HBO treatments involve placing patients in a hyperbaric chamber where they breathe100% oxygen at greater than atmospheric pressure. The extra oxygen that is dissolved in the plasma is then able to oxygenate the ischemic tissue to augment healing.
The future of wound healing is bright. The advent of wound care centers which emphasize early diagnosis, aggressive care, and a multidisciplinary approach will significantly improve outcomes and decrease morbidity. Aggessive wound care and appropriate use of HBO can be limb or life saving.