Simple Test Predicts Diabetes Amputation Success

Keeping blood sugar low could save lower limbs, research finds

FRIDAY, July 30, 2004 (HealthDayNews) -- Each year, more than 10,000 Americans with diabetes face agonizing decisions as the disease leads to foot ulcers that just won't heal, indicating a need for amputation.

In about 75 percent of cases, the partial amputation of a foot may be enough to stop ulcer progression. But for the remaining 25 percent, this type of operation will fail, leaving doctors no choice but to remove the leg from below the knee in yet another costly and painful surgery.

Now, Canadian researchers say a simple blood sugar reading can predict which patients will fare best with partial-foot amputations.

"The findings underscore the importance of controlling blood sugar after the surgical procedure is done," said Dr. Eugene Barrett, past president of the American Diabetes Association. "This points out that if blood sugar is poorly controlled, then the likelihood of success is diminished."

The finding was presented July 29 at the annual meeting of the American Orthopaedic Foot and Ankle Society in Seattle.

Chronic diabetes can restrict blood flow to the lower limbs, especially in older individuals. Poorer blood flow means impaired healing, raising risks for hard-to-treat diabetic ulcers.

Complicating matters, many patients also suffer from diabetic neuropathy -- a deadening of nerves in the feet and legs -- that leaves them without the sensation of pain that might otherwise send them into early treatment.

Neuropathy can leave feet and lower legs so numb patients "could walk around with a nail under their foot for a day and not realize it," Barrett explained. By the time many patients seek treatment, their ulcers are already surrounded by gangrenous tissue and the foot or limb cannot be saved.

In the past, a below-the-knee removal of the affected leg was standard procedure. But over the past decade, a limb-sparing surgery called transmetatarsal amputation (TMA) has become more popular, where just the front part of the foot is removed.

For most, amputation stops there. TMA fails some patients, however, leaving them no choice but below-the-knee amputation.

In their study, researchers Dr. Alastair Younger and Dr. Colin Meakin, of St. Paul's Hospital in Vancouver, looked for markers that could predict those patients in whom TMA would be most successful. They compared factors such as age, smoking status, duration of ulcer, and blood sugar levels in 21 diabetic patients for whom TMA was successful and 21 patients for whom the operation had failed.

The study found that, in patients with blood sugar levels greater than 10 percent of the blood "the TMA is bound to fail," Younger said in a prepared statement. These patients may require full below-the-knee surgery, and should not be put through the prior stress and expense of partial amputation.

On the other hand, in patients with blood sugar levels of 7 percent or lower "the rate of success is high, and a surgeon should perform a TMA," Younger said.

Barrett had one caveat to add, however. In his opinion, too many U.S. doctors still don't realize a surgical alternative to below-the-knee amputation even exists.

"The people who end up doing this procedure [below-the-knee amputation] are usually general surgeons or orthopedic surgeons," many of whom received their training prior to the advent of TMA, he explained. "If when they were trained they were told, 'For diabetic foot ulcer, you do a below-the-knee amputation,' that's what they do." According to Barrett, better education of surgeons may be key to saving more limbs through TMA.

Diabetic foot ulcers can also have a devastating impact on patients' psychological well-being, according to a second study presented at the Seattle meeting by Dr. Michael Pinzur of Loyola University Medical Center in Chicago.

According to Pinzur, patients treated for foot ulcers experience bouts of deep depression just as frequently as patients who have already undergone amputation, probably because these ulcers so often precede amputation.

"There's something very profound that occurs when you tell someone that they're going to lose a foot or leg," Barrett said. "I've had patients say that they'd just as soon die."

According to Pinzur, that's just one more reason to opt for the less-disabling TMA procedure whenever possible. In a prepared statement, he said experts must "work to come up with methods of treatment that will not impact [patients'] lives as much as it does now."

More information

To learn more about diabetic foot ulcers, visit the American Diabetes Association.

SOURCES: Eugene Barrett, M.D., professor, medicine, University of Virginia, Charlottesville; July 29, 2004, scientific presentations, American Orthopaedic Foot and Ankle Society annual meeting, Seattle
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