Device could help people with diabetes avoid foot amputations and other complications.

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Researchers at Purdue University have come up with an insole that can be tailored to individuals with diabetes. Photo/Courtesy of Purdue University image/Kayla Wiles

When it comes to treating, managing, and preventing diabetes-related complications, it seems oxygen is a key ingredient.

Along that line, researchers at Purdue University have created a customizable insole to treat diabetic foot ulcers.

It’s similar to evolving medical technology with contact lenses that help prevent and treat diabetic retinopathy.

In people with diabetes, a simple cut or blister on the foot can quickly become a much bigger problem.

As sugar in the bloodstream accumulates around nerve endings in the hands, feet, and eyes, the oxygen supply to those areas is greatly reduced.

If that simple cut or blister has trouble healing, it’ll likely become infected. Left untreated, often due to the loss of sensation in toes and feet from diabetes, the infection can become life-threatening and require amputation.

Foot ulcers, according to the Centers for Disease Control and Prevention (CDC), are the most common event that leads to amputation in people with diabetes.

“We typically treat ulcers by removing devitalized tissue from the surface of the wound and by helping the patient to find ways to take the weight off the affected foot,” said Dr. Desmond Bell, a podiatrist specializing in wound management and amputation prevention at the Memorial Hospital in Jacksonville, Florida, and the founder of the Save a Leg, Save a Life Foundation.

While total-contact casting has proven effective for healing foot ulcers in some people, its track record isn’t perfect, creating a need for other treatment ideas.

“Ulcers with moderate ischemia or infection can be treated effectively with casting,” explained researchers in a 2005 study published in the American Diabetes Association’s Diabetes Care journal. “However, when both peripheral arterial disease and infection are present or the patient has a heel ulcer, outcome is poor and alternative strategies should be sought.”

Purdue’s insole technology is designed to bring more oxygen to the sole of the foot, improving its ability to heal from simple ulcers, cuts, and blisters.

But the insole doesn’t go inside of your shoe.

“The gold standard for treating an ulcer is a patient wearing a total-contact cast,” Bell explained, “which provides a protective environment for the foot. If we could test how well this insole delivers oxygen to the wound site from within the cast, then this could be a way of aiding the healing process.”

The insole may look like it simply has a series of holes cut out of it, but its design is far more complex.

Using a silicone-based rubber, the insole is specifically designed for each patient based on the location of their ulcer.

Small reservoirs containing oxygen are created in the targeted area of the foot to help the ulcer heal properly and more quickly.

“When loaded with a pressure of [typical standing and walking], the insole is able to release oxygen at a rate of 1.8 mmHg/min/cm2,” explained Purdue’s report.

If the person is sitting, the oxygen delivery continues, creating the ideal environment for healing.

When studied, the insole was able to deliver oxygen for a minimum of eight hours a day, including when the person is standing.

To make the insoles more affordable and easily accessible, the team plans to create a variety of prefilled insoles with a variety of common foot locations.

People with diabetes would then get a prescription from their doctor for an insole that meets the needs of their ulcer.

The technology hasn’t been tested on people yet. And its patent is still pending.

While this advanced insole technology may help treat existing ulcers, it’s still imperative that people with diabetes focus on improving their blood sugar levels and overall health to prevent future infections.

The recurrence rate of foot ulcers in people with diabetes is high, according to a 2017 article from the New England Journal of Medicine (NEJM).

“By reviewing 19 compatible studies on incidence rates for ulcer recurrence, we estimate that roughly 40 percent of patients have a recurrence within one year after ulcer healing, almost 60 percent within three years, and 65 percent within five years,” explained the NEJM researchers.

They suggest that people be encouraged to think of foot ulcers as a long-term issue to encourage extra preventive measures, such as improving blood sugar levels, examining feet on a weekly basis, and changing socks halfway through the day to keep feet dry.

“It may be more useful to think of patients who have achieved wound closure as being in remission rather than being healed,” the NEJM researchers stated.