December 2013

New Threatened Limb Classification System ‘Focuses On Whole Limb’

By Brian McCurdy, Senior Editor

A number of existing classification systems for threatened lower extremities gauge patients’ ischemia but can fail to consider factors such as tissue loss or the extent of infection. A new system, recently published online in the Journal of Vascular Surgery, proposes to classify at-risk limbs with a broader range of criteria.

   The new classification, dubbed WIfI, uses three criteria: wounds, ischemia and foot infection. The system grades each of the three factors on a scale of 0 to 3, signifying low risk, mild risk, moderate risk or severe risk. The authors note that this system combines previous classification systems that focus on diabetic foot ulcers with those that focus on pure ischemia. Researchers add that the new system is necessary because four decades of demographic shifts, particularly rising diabetes prevalence and rapidly expanding revascularization techniques, have made it more challenging to perform meaningful outcomes analysis using present classification systems for those with threatened limbs.

   The difference between the WIfI and existing systems is that the new classification does not specifically focus on the wound, the presence or absence of infection or the vascular classification, but instead takes all three factors into account, says co-author David G. Armstrong, DPM, MD, PhD. As he notes, the WIfI focuses on “not the hole in the foot but the whole limb.”

   As co-author Joseph L. Mills, Sr., MD, notes, since a threatened limb can occur in patients without diabetes, the system can classify the disease burden of any presenting patient, even those without diabetes. He compares the classification to the TNM cancer classification, which considers tumors, lymph nodes and metastasis to stage the burden of disease.

   As the study notes, both the Fontaine and Rutherford systems, which stratify lower extremity ischemia, lack detail and most systems that classify diabetic foot ulcers give the details of perfusion status but do not take gangrene into account. Dr. Mills agrees, adding that most diabetic foot ulcer systems use peripheral arterial disease (PAD) as a “yes or no” classifier, saying this can be a problem since this does not grade ischemia. In addition, he notes vascular language can ignore the presence of infection by focusing only on blood flow.

   “The Eurodiale study and other studies demonstrate clearly that the combination of PAD and infection triples amputation risk,” according to Dr. Mills, who is affiliated with the Southern Arizona Limb Salvage Alliance (SALSA) at the University of Arizona Health Sciences Center.

   Both authors compared the WIfI to the universal language of Esperanto or bringing together the SALSA concepts of “toe and flow.”

   “It allows us to speak together to get the same language and not speak in tongues,” says Dr. Armstrong, a Professor of Surgery and the Director of the SALSA program at the University of Arizona Health Sciences Center.

Can The Percutaneous Tenotomy Be Useful In Treating DFUs?

By Danielle Chicano, Editorial Associate

Patients with diabetic neuropathy who suffer from diabetic foot ulcers have a higher risk of foot amputations. A recent study in Foot and Ankle International says percutaneous tenotomy can be an effective treatment for diabetic foot ulcers.

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