Saturday, November 21, 2009

WOUND HEALING


Approximately 6 million people suffer from chronic wounds, and the medical community is using multiple technologies to address this difficult problem. Why do people develop wounds, and why do some wounds not heal and become chronic wounds?  There are many etiologies of chronic wounds.  Diabetics are slow to heal because of small vessel disease and sensory disturbances, especially in the feet. Paraplegics develop chronic wounds because of lack of sensation and un-relieved pressure, which in turn "cuts off" the blood supply leading to "pressure sores". Shearing of skin during transfer can also be a factor.  Peripheral vascular disease (P.V.D.) can lead to chronic wounds due to lack of blood supply. Venous stasis disease can lead to lower extremity tissue break-down because of pooling of blood products in the tissues.  Cigarette smoking and nicotine products compromie healing because of their vaso-constrictive properties. Patients with immuno-compromise such as Acquired Immunity Deficiency Syndrome (AIDS) show poor healing capabilities.  Certain medications can also reduce the body's immune defense (such as steroids) and adversely affect wound healing. Some infections can cause significant tissue necrosis and lead to chronic wounds.

Many wounds will heal with time if given proper wound care.  The important principles of wound care include removing all unhealthy and/or devitalized tissues, removing any foreign bodies in the depth of the wound (such as wires and screws), controlling infection, off-loading any pressure on the wound, and providing the proper balance of hydration to the tissues. In the past, it was thought that we needed to let wounds dry out and scab in order to achieve healing. We now know that a wound will heal better in a moist envirnoment.  There are many wound-care dressings that are used to ensure the proper balance of moisture in a wound.

Topical growth factors have received much attention in the last several years as a way of speeding up the healing process. Hyperbaric Oxygen Therapy (H.B.O.) has been shown to improve healing in many patients by "super-saturating" the tissues with 100% oxygen.  This increased oxygen level stimulates new blood vessel  formation.  It also allows more white blood cells and antibiotics to reach the wound which help fight infection.  Electrical stimulation to a wound can be beneficial in some situations. Negative pressure wound therapy (N.P.W.T.) has been a gigantic leap in the treatment of chronic wounds. A sponge dressing is placed on the wound which incorporates negative pressure applied 24/7.  This negative pressure "sucks out" unhealthy fluids, stimulates granulation tissue (one of the first steps in healing) and shrinks the wound in all dimensions. One of the more popular units is called the V.A.C. (Vaccum Assisted Closure).  A new ultrasound treatment called Mist Therapy (Celleration of Eden Prairie, MN) has been developed to promote healing. Ultrasonic energy has been used in the past with varying degrees of success.  This new device that looks like a plant mister sprays saline droplets on the wound that carry ultrasonic energy. The ultrasonic energy dilates blood vessels and stimulates new vessel formation which increases blood flow and oxygen into the tissues.

Plastic Surgeons are an integral part of the wound care team.  They provide conservative care with some of the above mentioned tecniques, but also perform surgery to close wounds.  Many of these surgical procedures involve muscle flaps to bring in a new blood supply to the wound or micro-vascular transfer of tissue to promote healing. Chronic wounds are a challenging problem and require much skill and expertise.  Patients need to realize that this can be a long and slow process.