Effectiveness of scalpel debridement in diabetics using near infrared imaging technology for ulcer prevention

Abstract

Complications of the diabetic foot proliferate from ischemic and/or neuropathic conditions in the form of excess tissue build-up or callus. Plantar calluses are thick and soft and form as a result of neuropathy at the toe apices and metatarsals head and/or toe tips. Neuro-ischemic calluses appear thin, hard, dry and/or glassy and typically form at the borders of the feet and/or on main weight bearing areas. It is standard practice for the clinician to remove this excess tissue to reduce pressure in the diabetic foot which reduces the risk of ulceration. The dead tissue layers are removed in a surgical process known as scalpel debridement, or chiropody. It is not uncommon for a clinician to encounter a buried wound in the process of scalpel debridement. However, the process itself is not straightforward in that the extent of debridement is not measurable between clinicians. The debridement process removes tissue up to the epidermal-dermal junction, which may be difficult to identify for an inexperienced clinician. In an effort to measure the effect of scalpel debridement, near infrared (NIR) imaging was applied in an IRB study between Florida International University and Dr. Mohan’s Diabetes Specialties Centre in Chennai, India. Subjects were assessed before and after the debridement procedure. NIR images at multiple wavelengths were obtained before and after debridement to estimate changes in tissue oxygenation in the callus and surrounding peri-callus regions. A method to analyze the significance of oxygenation change occurring both overall and within sub-quadrants of the callus is conducted to assess the effect of debridement. Measuring changes in tissue oxygenation may potentially be used in future clinical applications to improve the debridement process and reduce the risk of ulceration.