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New treatments may help prevent amputations
Vigilance has long been the watchword in treating the feet of diabetic patients. Even so, up to 15% of all people with diabetes suffer a lower extremity amputation sometime in their lifetimes.
And as the incidence of diabetes increases and the diabetic population ages, the rate of foot ulcers is increasing at an even faster pace with the number of amputation increasing 29% in the 1980s.
Yet, the American Diabetes Association (ADA) says simple and inexpensive interventions can decrease the amputation rate by 85%. There are also some interesting new treatments already in use that can provide relief in extreme cases just short of amputation.
"The key is prevention. If we can identify those at high risk and target service to them, we’ll improve outcomes and prevent amputations," says Lee Sanders, DPM, the ADA’s vice-president for health care and education who practices at the VA Medical Center in Lebanon, PA. (See patient foot care checklist, inserted in this issue.)
The ADA recommends an annual foot exam for all patients with diabetes and more often for those at high risk.
The following are risks to foot health:
• Compared to the general diabetic population, those over 65 who have had the disease for more than 10 years face twice the risk of needing an amputation.
• Males have a 1.6-fold increased risk of ulcers and as much as 6.5-fold risk of amputation compared to females.
• African-Americans and Hispanics have about twice the risk of amputation, and some Native American tribes have a four-fold higher rate than whites with diabetes.
• Living alone presents up to 3.8-fold increase risk of amputation.
• Comorbid conditions, including diabetic retinopathy, renal disease, and macrovascular disease such as coronary artery disease are major risk factors.
• Lack of patient education on foot-care methods more than triples the risk of amputation.
Sanders says a clinician should check patients’ feet at every checkup, examining the skin for breaks, color changes, and overall integrity and texture. The clinician should also look out for any deformities to the feet and take pedal pulses.
He says the simplest screening technique is the use of a Semmes-Weinstein 5.07 monofilament used to test sensation in the foot, which is available at most medical supply centers. "Every physician who is seeing diabetic patients should have one of these in his pocket," says Sanders.
"If they can’t feel that monofilament, then they’ve lost their protective sensation and they are at high risk for foot ulcers and possible eventual amputation," says Vincent Giacalone, DPM, a podiatrist at the Hackensack University Medical Center and the Pascack Valley Hospital in Westwood, NJ. He also is a member of the diabetes advisory committee of the American Podiatric Medical Association.
Giacalone explains the importance of performing such tests because patients might not notice the gradual and painless loss of sensation on their own.
Beyond the simple screening devices that virtually any clinician can perform, signs of abnormality should be a signal for referral to a podiatrist or an orthopedist for further investigation.
Many specialists have pressure plate sensors in their offices, which can help determine weight distribution and detect pressure points that could cause an ulcer. "The patient walks across a gait platform that picks up pressure on the ball of the foot. When they place a lot more pressure on the ball of the foot, they are vulnerable to ulcers," Giacalone says. The key, he says, is to get the pressure off, whether through inserts or special shoes. Once an ulcer develops, the treatment is far more difficult, he says, and signals the time when a primary care physician should consider a referral if one has not already been made.
"Most often, we see patients with ulcers that are not responding to care by primary care physicians because they are not getting the pressure off. Getting the pressure off is the key to healing those ulcers," he adds.
Treatment involves weekly debridement, healing sandals, and sometimes, total contact casts replaced weekly for several weeks.
In cases of stubborn ulcers that do not respond to conventional treatment, two new treatments have gained considerable attention.
The first is Regranex, a unique bioengineered gel that speeds healing. "It works very well; I like it, " says Giacalone.
Sanders says Regranex can play a "useful role," but its high cost precludes it from being a treatment of first choice. "It should be for those who haven’t done well with the simpler approaches," he says. (The medicine costs $350 to $400 per tube; patients usually need two tubes to treat their feet over a two-month period.)
Giacalone says in a year or so he expects bioengineered skin cultured from the foreskins of circumcised infants to become available.
Research is showing maggot therapy may become useful as well. But even though the creatures are cultured under sterile conditions, patients can be squeamish about inserting live maggots into their open ulcers. An Israeli study showed maggots applied from two to five times a week for 24 to 72 hours completely debrided 67% of foot ulcers within six weeks of use. Healthy new tissue had grown over the wound.
Giacalone says the treatment works because "maggots will only eat dead tissue," but adds, "Generally, we like to use a scalpel."
Other treatments require more tools than a scalpel. Perhaps most unconventional of the new treatments is a dramatic surgery called diabetic foot salvage and used for Charcot’s foot (a condition where bones in the foot collapse).
R.J. Sullivan, MD, an orthopedic surgeon at the University of Connecticut Health Center in Farmington, has had "good success" with the complex procedure that involves screws and wires in the bones and finally a plantar plate. He says he’s had a 75% to 80% success rate with the procedure, but cautions, "It’s a last attempt to salvage the foot before amputation."
Prevention is still the best way to tackle these problems, says Sanders, who says many of the serious diabetic foot problems can be stopped before they start with a simple foot exam every time a patient visits the primary care provider.
[Lee Sanders can be reached at (717) 228-5952. Contact Vincent Giacalone at (201) 445-2000 and R.J. Sullivan at (860) 679-6600.]