A Prospective, Single-Center, Nonblinded, Comparative, Postmarket Clinical Evaluation of a Bovine-Derived Collagen With Ionic Silver Dressing versus a Carboxymethylcellulose and Ionic Silver Dressing for the Reduction of Bioburden in Variable-Etiology, Bilateral Lower-Extremity Wounds

Abstract

There are numerous dressings designed to manage the overabundance of matrix metalloproteinases, while also addressing the excessive bioburden found in chronic wounds. The authors compared the efficacy of 2 such dressings: a sodium carboxymethylcellulose/1.2% ionic silver (CMC), which theoretically reduces bacteria by providing silver ions, versus a bovine native collagen (BDC)/ionic silver dressing, which also delivers silver ions in an aqueous environment. Both dressings theoretically modulate the wound bed; CMC through moist wound care and fibrin ingrowth and BDC through matrix metalloproteinase balancing. A prospective protocol was undertaken using patients as their own controls. Ten patients with bilateral venous stasis or diabetic foot ulcers were selected. One limb was randomized to treatment by either CMC or BDC, whereas the contralateral wound was treated with the other dressing. Biopsies for quantitative cultures were taken at weeks 1 and 4. Wound area was assessed at the weekly visits. The BDC wounds started with 1.0 × 10 (±1.2 × 10) bacteria, and the CMC wounds started with 1.4 × 10 (±1.3 × 10) bacteria. Over the 4-week period, the bacteria in the 3-ppm (parts per million) silver-treated wound increased 1.53 × 10, whereas in the 21-ppm silver-treated wound, the bacteria increased 1.42 × 10. The rates of closure for CMC-treated wounds was 0.79 ± 0.735 cm/wk and for BDC-treated wounds was 1.38 ± 1.44 cm/wk. Only 1 wound treated with either dressing exhibited a decrease in bacteria. Both CMC and BDC silver dressings appeared to have statistically similar efficacy regarding the rate of wound healing and little impact on the actual bioburden in chronic lower-extremity wounds. Interestingly, there was no correlation in the size of the wound and any effect on bioburden. Although the BDC dressing showed a higher absolute rate of wound closure, neither technology demonstrated a statistically significant difference in wound closure rate when corrected for initial wound size.