By Dr. Jayesh Shah, MD, CWS,
FAPWCA, FCCWS
Non-healing wounds are very common in diabetics. Twenty percent of hospital admissions of diabetics are because of lower limb problems. The incidence of amputation is six per 1,000. From 1993 to 1999, approximately 67,000 amputations were performed yearly among people with diabetes.
The risk of lower-extremity amputation in people with diabetes is 15 times higher than that of non-diabetics and the risk increases with age. A chronic renal failure patient with diabetes has a lower limb amputation rate 10 times greater than the diabetic population at large.
The human and financial costs of lower-extremity amputation in patients with diabetes mellitus are well recognized. However, the rates of major amputation in the United States remain high, in part because present knowledge regarding the prevention and management of foot disease is not widely applied in clinical practice.
The triad of peripheral neuropathy (loss of sensation), poor circulation and mechanical abnormality are the major contributing factors to the formation of diabetic foot ulcers. Approximately 60 percent of these ulcers are primarily neuropathic (loss of sensation), 20 percent are primarily ischemic (poor circulation) and 20 percent are both neuropathic and ischemic.
Structural abnormality in the foot contributes a lot to the formation of foot ulcers in diabetics because structural abnormality in the foot leads to increased pressure. With sustained repeated trauma, this increased pressure can cause tissue breakdown and ultimately ulceration that leads to
serious complications.
These three factors – neuropathy (loss of sensation), peripheral vascular disease (poor circulation) and mechanical abnormalities must be identified early and corrected to successfully reduce the amputation rate in the diabetic population. If a high risk foot is identified in a patient, the patient should see a primary care doctor at least every six months to make sure that foot is well protected with protective (orthotic) shoes and to get examined for any development of new ulcerations.
Diabetic vascular disease is usually combination of macro-vascular (large vessel) disease and microvascular (small vessel) disease. Patients with diabetic macrovascular disease can undergo revascularization, which has a reasonable chance of saving the limb.
A recent audit by the Vascular Surgical Society found a success rate of more than 70 percent for these patients. However, many patients still require a major amputation.
Although most diabetic foot ulcers will resolve with a comprehensive wound management program including aggressive revascularization when indicated, some patients will develop chronic, non-healing ulcers.
Inadequate treatment of chronic ulcers can lead to hospitalizations owing to the development of infections and gangrene, and many patients with such severe complications may ultimately undergo amputation of the affected limb.
In the past few years, there has been considerably better understanding in the healing of chronic, non-healing wounds. Multiple products and advanced dressing options are available to heal wounds faster at wound care centers. Some examples of these products are Wound Vaccum therapy (negative pressure therapy); bioengineered skin like Apligraf, Dermagraf, Integra, Graft Jacket and multiple others (artificial graft); Collagen dressings like OASIS, Promogran, Prisma and growth factors like platelet derived growth
factor or autologous platelet gel. New research in the field of diabetic wounds indicates a possible role of gene therapy and topical vascular endothelial growth factor in the future.
Sometimes, these advanced dressings are not able to heal wounds and there may be a need for hyperbaric oxygen therapy for selected, non-healing wounds. Hyperbaric oxygen therapy is selected for some diabetic wounds based on transcutaneous oxygen studies (TCPO2). TCPO2 measures tissue oxygen tension, which is direct, quantitative assessment of oxygen availability to the tissues. These studies help in vascular assessment, help to predict who will or who will not respond to treatment well, and help to choose successful amputation sites. These studies also are used to select candidates for HBO2 treatment by identifying the presence of tissue hypoxia and the responders to hyperoxia.
Hyperbaric oxygen therapy is a therapy during which the patient breathes pure 100 percent oxygen under increased atmospheric pressure. The air we normally breathe contains only 19 to 21 percent of this essential element. The concentration of oxygen normally dissolved in the blood stream is thus raised many times above normal (up to 2,000 percent). In addition to the blood, all body fluids including the lymph and cerebrospinal fluid are infused with healing
benefits of this molecular oxygen.
It allows oxygen to go to areas that are inaccessible to the red blood cells, enhances white blood cell function and promotes the formation of new capillary and peripheral blood vessels. This results in increased infection control and faster healing of a wide range of conditions.
Apart from the use of hyperbaric oxygen therapy in treatment of diabetic wounds, HBO is also used to treat bone infections, crush injuries, failing skin grafts, soft
tissue necrotising infections, gas gangrene, radiation tissue damage and other conditions.
Failure to heal an ulcer can often be traced. The most common pitfalls are: a “cavalier” attitude; W.N.L. exam (We Never Looked); inadequate off-loading; failure to establish depth of ulcer and miss “probe to bone” and failure to control edema.
The multidisciplinary wound care clinic model provides an ideal setting for early intervention, treatment and assistance with preventive strategies. At wound care clinics, a wound care doctor works with multiple disciplines such as podiatrists, plastic surgeons, orthopedic surgeons, vascular surgeons, endocrinologists, dieticians and orthotists to coordinate the care of a patient for achieving
optimal results.
Let us join hands with the American Diabetes Association and save limbs — and in turn save lives.
Dr. Shah is the president and medical director of South Texas Wound Associates, PA and medical director for the Center for Wound Care and Hyperbaric Medicine at Southwest General Hospital. He is board certified in Internal Medicine, Wound Care, Hyperbaric Medicine and Preventive Medicine.
