Abstract: Following standard care, nonhealing lower extremity (LE) ulcers were managed with a bacterial cellulose (BC) wound dressing, Dermafill™, (AMD/Ritmed, Tonawanda, NY), derived from Acetobacter xylinum. The time to 75% reduction in wound size was compared in 11 chronic wounds before and after the application of BC. The mean period of observation before the application of BC was 315 days; (95% CI: 239–392 days). With the application of BC to these chronic wounds, the mean time to 75% epithelization was reduced to 81 days (95% CI: 50–111 days) with a median of 79 days. The rate of wound closure with BC was significantly faster than with standard care (P < 0.001). When applied to nonhealing LE ulcers, a BC wound dressing shortens the time to wound closure over standard care.

Address correspondence to:
Dennis J. Levinson, MD
Department of Medicine
Michael Reese Hospital
2929 S. Ellis Ave.
Chicago, IL 60616
Phone: 312-791-2670
E-mail: djlevins@uic.edu

Disclosure: Dr. Levinson discloses stock ownership in MCT Woundcare, LLC, a distributor of microbial cellulose.

     Tissue viability, infection, moisture imbalance, and nonadvancing or undermined margins, are factors that may impede the wound healing process resulting in chronic nonhealing wounds.¹ Among the many factors involved in the management of the chronic wound, perhaps one of the most important is the wound dressing.² This retrospective, observational study reports initial results on the use of a transparent, semipermeable, occlusive, bacterial cellulose (BC) dressing derived from Acetobacter xylinum in nonhealing ulcers of the lower extremity (LE).

Materials and Methods

     The primary outcome was a sequential paired comparison of the rate of reduction in wound area during treatment with either standard dressings or BC. Only wounds that failed to heal following 60 or more days of treatment with standard dressings were selected for application of BC. Time to 75% epithelization was selected as the endpoint, since this provided an equivalent endpoint that could be compared for the same wound treated with standard and BC dressings. The study population was derived from a retrospective chart review of patients who received treatment in the outpatient wound care clinic at Michael Reese Hospital (Chicago, IL). Patients were excluded if they had evidence of infections such as osteomyelitis, cellulitis, cancer, or renal failure. Standard care included either enzymatic, mechanical or sharp debridement (as needed), 2- or 4-layer bandages for venous hypertension, and off-loading for diabetic ulcers. Wound dressings employed in standard treatment of chronic wounds before the application of BC included gauze, foams and alginates, composites, and silver impregnated polymers. The protocol was approved by the hospital’s independent review board.

Statistical Analysis

     The outcome measurement was the rate of relative reduction in wound area. A baseline measurement at the first clinic visit was used for calculation of the change in wound area. In nonhealing wounds where BC was applied to wounds previously treated with standard dressings, the baseline area of the wound was reset to the area at the time of initial BC application. Kaplan-Meier analysis was applied to estimate the time to the outcome event—the time to the first clinic visit where the percent area epithelized was greater than 75%.

Results

     In chronic LE ulcers that failed to heal using standard dressings, BC was applied to the same wounds, and the time to 75% reduction in wound size was compared to wound size and duration prior to BC application. Eleven patients were evaluated, 6 (55%) of whom were women. The average age was 70 years with a range of 51 to 87 years. Six patients had diabetes and 5 had a post-phlebitic syndrome.