New Technology Helps Speed Diabetic Foot Wound Healing
Jeffrey A. Niezgoda, MD, FACHM, FAPWCA, Kimberly Eldridge, RN, CWS, Richard Millis, PhD, Milton Kondiles, DPM and Rebecca D. Snarski, PhD
Wound Healing in Diabetics
For those with diabetes, careful management of blood sugar is imperative to prevent any number of complications, including those that contribute to poor wound healing, which is so common in diabetics. One such problem, seen in 15% of individuals with diabetes, is the development of the foot ulcer (1; 2). Diabetic foot ulcers are significant problems as they can lead to amputation of a patient’s foot or even the entire leg (1). In fact, more than half of the people who undergo lower limb amputations in the United States each year suffer from diabetes (3). Due to the serious issue of wound healing in diabetics, it is important for those living with the disease to understand the nature of foot wounds and the current technology available in wound care, including new treatments that can promote fast healing, preventing wounds from becoming chronic.
Understanding Foot Ulcers
A foot ulcer refers to any open break in the skin of the foot. While these can sometimes be shallow, often they are quite thick, extending through multiple skin layers. These wounds usually have low oxygen levels due to poor circulation (ischemia) or include injury to the nervous system (neuropathy); uncontrolled blood sugar levels can lead to both. Once a foot ulcer occurs, ischemia can lead to slow healing and tissue death, while the neuropathic loss of sensation can cause the wound to go unnoticed and untreated. In diabetics, foot ulcers often become chronically un-healing wounds, and result in amputation in 85% of cases (2). These ulcers can be exacerbated by other diabetic conditions.
Approximately 60% to 70% of diabetic patients develop diabetic neuropathy (4). This is a form of nerve damage caused by prolonged abnormal elevations in blood sugar. Diabetic neuropathy places a person at significant risk for the development of foot ulcers, as the nerve damage decreases the sensation in the foot. Diabetics with neuropathy can no longer sufficiently detect trauma as their pain sensation is blunted. It is common for a diabetic with neuropathy to walk all day on a blister, or to not notice the pain from a needle or nail that has punctured their foot, leaving the wound untreated to become serious.
Diabetics frequently experience poor blood flow to their legs, feet and toes due to another complication of diabetes, peripheral arterial disease (PAD). PAD is the narrowing of the blood vessels which carry blood to the legs. Such circulation issues can cause worsening of skin injuries or prevent healing in patients with diabetic foot ulcers. Decreased blood flow results in ischemia (the limitation of oxygen delivery to the tissues) or hypoxia (abnormal oxygen levels in blood and tissue) (4). Since oxygen is a necessary component of cell regeneration, ischemic and hypoxic tissue is less likely to heal and is also at higher risk for infection. The combination of neuropathy and PAD often results in foot ulcers that deteriorate, rather than heal. Complications related to chronic diabetic foot ulcers include cellulitis (infection of the skin and soft tissue), osteomyelitis (bone infection), and gangrene (tissue death). All of these issues place the diabetic at a high risk for amputation, therefore aggressive and early treatment of such foot wounds is essential.
Traditional Treatment of Diabetic Foot Wounds
Traditionally, several different methods have been used to treat diabetic foot wounds or ulcers. Casts and bed rest are sometimes prescribed to reduce pressure and repeated trauma. While preventing additional injury is important, this does not help circulation or actual healing. Topical antibiotics are sometimes prescribed. These can help prevent infection, but do not necessarily speed healing. Furthermore, overuse of antibiotics can lead to antibiotic resistance, which can be a serious problem for diabetics. Moist dressings are often prescribed. These are helpful, as they create a moist environment which has been shown to promote better healing than dry dressings (1). In serious situations, debridement (removal of dead tissue) is conducted (1). Whirlpool therapy is sometimes used effectively to clean wounds and to stimulate circulation, particularly in necrotic wounds with high levels of exudate (draining fluids) (5).
Despite even aggressive treatments, the underlying cause of diabetic foot ulcers is not fully addressed or corrected with these procedures. Neuropathy, tissue ischemia and hypoxia, and excess oxygen free radicals continue to place the diabetic patient at risk for deterioration of the foot ulcers and ultimately at risk for amputation (3).
Oxygen Free Radicals’ Impact on Diabetic Wound Healing
As noted, oxygen is an important part of good healing. By contrast, the healing process often generates oxygen free radicals, which can cause inflammation and slow healing (6, 13), and can destroy surrounding healthy tissue. In healthy individuals, the cell damaging effects of oxygen-derived free radicals is mitigated by antioxidant defense and scavenging systems (6). In diabetic patients, however, the oxidant/antioxidant balance is forced into disequilibrium (6). Nonenzymatic protein glycosylation and glucose autooxidation are the two most-cited factors that can disrupt the control of oxygen free radicals and antioxidants in patients who have diabetes. Diabetic wound healing can be so significantly compromised that mortality rates are very high with chronic foot wounds. In fact, up to 25% of all hospital admissions involving diabetic patients are related to foot complications, including ulcers (7).
Combined with ischemic and neuropathic complications, the introduction of uncontrolled oxygen free radicals further serves to compromise patients with diabetes. This results in potentially worsening foot ulcers and increased difficulty in their treatment. Oxygen free radicals can cause damage at the cellular level, which can make treating diabetic foot wounds through traditional methods even less effective. However, there are some effective treatments to help re-oxygenate the wound and minimize the damage caused by radicals.
Promoting Healing by Treating Oxygen Issues
Oxygen itself is a critical component of wound healing, and the effect of hypoxia in diabetics has been studied at length. Furthermore, diabetic disease results in many complications and cellular discrepancy including the reduced ability to produce antioxidants, leading to oxygen free radical imbalance. Numerous studies have shown a direct correlation between delayed wound healing and the presence of excess oxygen free radicals (8). Excessive amounts of reactive oxygen molecules can lead to exacerbation of diabetic foot disease, deterioration of foot ulcers and refractory healing of these wounds. Ultimately the diabetic patient is at high risk for amputation, and extreme rates of morbidity.
In order to mitigate the damaging effects of oxygen free radicals, and to offset the complications of hypoxia and ischemia often present in diabetic foot ulcers, an increasingly popular treatment is hyperbaric oxygen therapy (HBOT) (9). During hyperbaric treatment the patient breathes 100% oxygen while being exposed to increased atmospheric pressure (3, 9, 10). Used as an effective wound healing treatment for over forty years, HBOT helps bring the healing affects of oxygen to a wound, while decreasing inflammation, assisting white blood cells, and helping to kill bacteria (3). While often effective, HBOT is time consuming and expensive, often requiring up to 30 treatments. Thus the use of HBOT is typically limited to treating patients with infections or gangrene, who are at extreme risk for limb loss (11.
Wounds that heal quickly heal the most efficiently (12) and with the fewest complications. It is clear that newer and alternative treatments are necessary for the fast and proper treatment of diabetic foot disease. Novel therapies for the control of oxygen free radicals are being investigated. Topical gels with oxygen free radical scavenging properties have been developed and approved for patient use. This therapy has been shown clinically to stabilize the inflammation associated with diabetic foot ulcers and other wounds, contributing toward improved wound healing. One such gel currently on the market includes FDA approved ingredients that bind with oxygen free radicals, neutralizing them, while also providing a moist healing environment to speed healing time. While such technology has a strong ability to accelerate and improve healing, it is also easy to use, inexpensive, and non-invasive. While additional research regarding this technology is warranted, this novel therapeutic option carries the hope of providing a safe, inexpensive and effective treatment for a disease that is ravaging patients across our nation.
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