Polyurethane foam sheets for relieving pressure from diabetic neuropathic plantar ulcers: a pilot study

Abstract

INTRODUCTION: Lesions of the diabetic neuropathic foot are mainly caused by pressure in anatomically altered areas. This leads to hyperkeratosis, skin disruption and finally to ulcerations that can progress to underlying bone. Therapy for plantar neuropathic ulcerations in diabetic patients involves relieving pressure from ulcerated areas to allow re-epithelialization. Traditional methods, such as casts, orthoses and special shoes, are not well tolerated by patients. OBJECTIVE: To test whether polyurethane foam sheets, regularly used for dressing neuropathic ulcers of the diabetic foot, may also play a role in pressure relieving, we conducted a pilot study in a group of neuropathic diabetic outpatients. METHODS: Ten diabetic patients with non-complicated neuropathic plantar ulcerations were consecutively selected among the attenders of our diabetic foot clinic. The patients underwent careful debridement of the ulcerated area and elimination of perilesional hyperkeratosis. The ulcers were then covered with semipermeable film to allow measurements to be made. An evaluation of static and dynamic plantar pressure was then performed with F-SCAN, specialized software that analyses data collected from two 960-LED insoles (one for each foot). Static plantar pressures were acquired after patients had stood still on both feet for 15 s, while dynamic pressures were measured after walking for 2 min. The same evaluations were performed after positioning over and around the ulcers a double layer of polyurethane foam sheeting (Allevyn Adhesive) tailored to adapt to the conformation of the foot. The following parameters were then evaluated: peak pressure (PP: kPa); areas of peak pressure (APP:cm 2 ); time of application of peak pressure (TPP:s). RESULTS: The PP was significantly lower after application of the polyurethane sheeting (P<0.01), while the APP significantly increased (P<0.001). No significant differences were observed for TPP. Differences in PP (Delta PP) and in APP (Delta APP) were then calculated: Delta PP significantly inversely correlated with Delta APP, both in static and in dynamic conditions (P<0.001). CONCLUSION: Polyurethane foam sheets proved to be effective in reducing plantar pressures in neuropathic feet, probably because of an increased area of pressure distribution. Further studies are necessary to verify whether the use of this material could actually reduce the healing time of neuropathic ulcers in diabetic patients. (J Dermatol Treat (2000) 11:39–42)