Can Silver Heal Wounds?
The patient’s wound was large, complicated and painful. The 68-year-old man came to see wound care expert George J. Koullias, MD, a vascular surgeon at Stony Brook Surgical Associates, in New York, with a large mixed ulcer that had been plaguing him for two years. The bone was exposed, and part of the wound was necrotic. His doctor had referred him to Dr. Koullias for amputation.
But Dr. Koullias wanted to try something else. After extensive debridement of the wound, the patient had a series of biofilm control–based dressing applications and placental allografts. Then for the last year, after the wound was in a healing trajectory, he applied—and reapplied—Aquacel Ag (ConvaTec), a hydrofiber dressing that contains silver. For almost one year, the patient reapplied the product every 48 hours. “Gradually, it led to a complete healing of two major wounds,” Dr. Koullias said during a presentation at the Symposium on Advanced Wound Care 2020 virtual meeting. No amputation was necessary: “We’ve seen him a few weeks ago, and he is doing great.”
Clinicians have been using silver, which has strong antimicrobial activity, in wound care for more than 2,000 years. However, it also can impair healing by damaging some cell types, and research about its benefits has produced mixed results (Plast Reconstr Surg Glob Open 2019;7:e2390). So what is fact, and what is fiction?
Fact or Fiction: Silver Can Delay Healing
Unpublished data from a ConvaTec study that compared Aquacel Ag (both its original and updated versions, Extra and Advantage, respectively) with a wound dressing without silver (Tegaderm, 3M) in an acute porcine wound model found equal rates of healing. Based on these results, David Parsons, PhD, FRSC, the director of science and technology at ConvaTec, in Deeside, Wales, concluded that Aquacel Ag products “do not hinder the wound healing process.”
That may not apply to all wounds and silver products, said Jeffrey E. Janis, MD, a professor of plastic surgery at the Ohio State University Wexner Medical Center, in Columbus. In a 2019 review of nearly 60 studies that examined silver’s benefits in wound care, Dr. Janis found that dosing matters (Plast Reconstr Surg Glob Open 2019;7:e2390). “Not enough ionic silver doesn’t have any benefit, and too much may be too much of a good thing.” That “sweet spot” seems to be a sustained dose between 30 and 60 ppm, he said; anything above that seems to slow healing, he said, likely by damaging keratinocytes and fibroblasts. “We don’t want major bucket dumps of silver ions.”
Answer: fiction (when used properly)
Fact or Fiction: Silver Increases Antimicrobial Resistance
Resistance is always a concern with any anti-infective agent, Dr. Parsons said, but there hasn’t been any clinical evidence of a concern with silver. “When challenged with silver, 100% of tested organisms are eliminated.” ConvaTec has found that the Aquacel Ag Advantage product is effective in vitro against all forms of bacteria, including superbugs. “We have yet to find a wound pathogen that can’t be cleared with our silver dressings,” he said.
Dr. Janis, also the chief of plastic surgery at Wexner Medical Center, agreed, noting that despite the fact that silver has been around for thousands of years, “I haven’t seen any data that resistance is built up to it.”
Fact or Fiction: Silver Helps With Wound Care
In a 2015 paper, more than 100 patients received Aquacel Ag for various types of hard-to-heal wounds; over an average treatment period of four weeks, the majority of wounds (95%) healed or improved, and 17% healed completely (J Wound Care 2015;24:11-22). “That’s quite remarkable,” said Dr. Parsons, who co-authored the study. But some formulations of silver work better than others, he cautioned. “It’s impossible to generalize about silver dressings,” he told meeting attendees.
“Silver can definitely be effective,” Dr. Janis said. “And that’s what the literature would say.” He agreed with Dr. Parsons that the metal needs to be in a usable form—ionic—and the data would only support its limited use in specific indications (see “tips”). He said he regularly uses Aquacel Ag and other silver-containing products to facilitate wound healing in his patients in the appropriate circumstances, specifically around infected wounds for a short period of time. “We see silver is effective when being used correctly.”
Disclosures: ConvaTec sells Aquacel Ag, a wound care product that contains silver. Dr. Janis reported no relevant financial conflicts of interest.