Introduction

Leg ulcer and bedsore are frequently encountered in daily clinical practice and are considered as difficult-to-treat conditions because they usually require a long course of treatment. This report describes our recent experience with a new treatment strategy for these conditions with favorable outcomes.

Materials

Gelatin powder irreversibly gelated with formaldehyde, and gauze coated with gelatin on both sides and treated with formaldehyde to gelate the gelatin and sterilized, were used.

Method of application

Gelatin powder was sprinkled directly onto small lesions of leg ulcer and intractable ulcer. For medium-to-large ulcers, gelatin gauze was applied onto the lesion without replacement, except when the ulcer became wet.

Outcome

The results are summarized in the table. Overall, the duration of treatment was shortened by the present treatment method. In a patient who concurrently developed ulcers in both legs, the duration of treatment was substantially shortened in the leg treated with the present method compared with the other leg which was treated with the conventional method (case 10).

Discussion

Leg ulcer and bedsore are generally considered intractable conditions as they are associated with focal circulatory disturbance and/or infection. However, we doubt that the reason for the intractableness of these conditions can be attributed to anatomical factors alone. Therefore, we considered that serum collected from the patient should be the most homogenous and non-allergic material that can be applied to their ulcer surface. We immersed sterile gauze in the serum, which was collected aseptically from the patient, and applied it onto the ulcer surface. This gauze was effective in promoting healing of the ulcer, but as the serum dried, the gauze stuck to the ulcer surface. An attempt to forcedly remove it resulted in damage to the cured ulcer surface, peeling of the epithelium that began to cover the ulcer surface, and bleeding from the surface.

To solve this problem, we sterilized gelatin and mixed it with the patient's sera and a small amount of antibiotics to prepare a paste. The paste was applied to cover the ulcer surface and covered with gauze, and a supporting cardboard was placed between the gauze and the skin to prevent direct contact between the gauze and the paste. A dressing was placed over the gauze overnight until the paste dried. After the past dried and formed an artificial scab, a dressing was placed over the scab to promote sub-scab healing. With this procedure, leg ulcers of about 2 cm in diameter were epithelialized and healed in about 10 days.

As our experience grew, we learned that an artificial scab can be formed and that our treatment goal can be achieved with gelatin powder alone. This also suggests the importance of the physical condition of the ulcer surface.

As we repeated this method in the treatment of ulcers, we realized that it is effective even when the gelatin did not dry because of the excessive exudate, which prevented formation of an artificial scab. This observation suggests that the physical conditions that allow gelatin to dry and form a scab are not the only factors for promoting healing. Gelatin is a protein composed of 18 amino acids. The physicochemical characteristics of serum and gelatin also appear to mediate the healing of leg ulcers.

The method using patient-derived serum is complicated and is disadvantageous in that gauze replacement is not performed easily. Drawing blood from a debilitated patients should also be avoided if possible.

The method using serum or gelatin is associated with the risk of infection if excessive exudate prevents immediate drying of the paste and subsequent scab formation, as serum and gelatin per se serve as culture media for bacteria. The addition of an antiseptic agent to the paste for the purpose of preventing infection will make it irritative to the ulcer surface, which is contrary to the initial objective of this treatment method.

By irreversibly gelating gelatin with formaldehyde, and then removing the excess formaldehyde, we were able to create gelatin that is susceptible to gelatinase activity but resistant to bacterial growth. We found that this gelatin was swollen, but not lysed, when exposed to excessive exudate and thus could be used conveniently and safety. A thin membrane made of this material would not serve as a culture medium for bacteria, is not dissolved by water or acid, is resistant to high-pressure sterilization techniques, and is convenient for application to large lesions of ulcer and bedsore.