CANCUN, MEXICO—AQUACEL Ag® SURGICAL cover dressing (ConvaTec, Bridgewater, N.J.), a hydrofiber wound dressing composed of moisture-activated carboxymethylcellulose fibers integrated with ionic silver, may provide benefit in patients at risk for infection, including those who undergo ventral hernia repair, according to a presentation during an industry-sponsored symposium at the 2017 annual meeting of the Americas Hernia Society.

Maurice Nahabedian, MD, professor and vice chair of plastic surgery at Georgetown University, in Washington, D.C., presented an overview of the risk factors for infection after ventral hernia surgery, and described the current evidence supporting AQUACEL Ag® SURGICAL for prevention of infections."Infection remains a persistent problem, so considerations for incisional dressings are becoming more relevant," he said."I don't know that just placing a dry gauze is sufficient.

"I think that there is clearly going to be an application for a sophisticated wound dressing like AQUACEL Ag® SURGICAL in the abdominal wall setting." A 2012 report in Annals of Surgery examined outcomes for 33,832 patients who underwent ventral hernia repair with mesh between Jan. 1, 2005, and April 4, 2010, at all American College of Surgeons National Surgical Quality Improvement Program–participating hospitals in the United States.1 It documented a significant increase in the risk for postoperative occurrences in clean-contaminated and contaminated cases, relative to clean cases. Surgical site occurrences were reported in 27.3% and 21.2% of patients with contaminated and clean-contaminated wounds, respectively, compared with 7% of patients with clean wounds. The most common pathogens associated with infections after ventral hernia repair/abdominal wall reconstruction are Staphylococcus aureus (30%), coagulase-negative Staphylococcus (11.7%), Enterococcus (11.6%), Escherichia coli (9.4%) and Pseudomonas (5.5%).2

Many patients who present with large abdominal hernias undergo elective surgery, which allows opportunity to optimize patients for surgery and reduce their risk for infection, Dr. Nahabedian said. Preoperative factors that can reduce a patient's risk include weight loss, smoking cessation, diabetes mellitus control and nutritional optimization. During the operation, surgeons must pay heed to skin prep, antibiotics, tissue perfusion, tension, drains, suture techniques and dressings. The role for incisional dressings in prevention of surgical site infections (SSIs) is not yet clear, he noted. The only consensus guidelines for the prevention of these infections do not address incisional dressings.3

The guidelines recommend that surgical teams cover the incision with sterile gauze for 24 to 48 hours, and use aseptic or a no-touch technique for dressing change. However, for patients with high-risk incisions with mild to heavy drainage, a growing body of evidence indicates that composite dressing such as AQUACEL Ag® SURGICAL with its dual-purpose composition—with a component to keep the wound moist and absorbent, and another to kill bacteria—has a role in infection prevention, Dr. Nahabedian said.

AQUACEL Ag® SURGICAL's hydrofiber technology transforms into a gel on contact with wound fluid, creating an optical environment for wound healing, according to in vitro studies.4 Its active ingredient, a silver ion, deactivates many of the enzymes needed for cellular respiration. Silver has a broad spectrum of activity with both bactericidal and bacteriostatic properties, is nontoxic to human cells, and is effective against bacteria, fungi and viruses, as well as methicillin-resistant S. aureus and vancomycin-resistant enterococci. AQUACEL Ag® SURGICAL 1.2% silver is distributed throughout the dressing material, which allows it to be slowly released for up to two weeks as the hydrofiber carrier is hydrated. The dressing maintains its antimicrobial capability for approximately one week, and entraps microorganisms within its fibers.

Dr. Nahabedian described how he uses AQUACEL Ag® SURGICAL:"The reality is it will give you significant or beneficial bactericidal and bacteriostatic activity for about seven days, so you can leave these dressings on for a week. You can peel them off in the hospital if the patient is still in the hospital or in the office, which is typically what I will do."As you peel it off, you'll be able to see the hydrofiber that's somewhat gelatinous, and you'll also see some of the debris or blood products in the fiber." To date, five randomized controlled studies and several retrospective reviews of AQUACEL Ag® SURGICAL have been reported, mostly in orthopedic and chronic wound populations.

Of the more recent reports, a 2015 study that randomly assigned 262 orthopedic patients to either AQUACEL Ag® SURGICAL or Primapore found that AQUACEL Ag® SURGICAL was associated with a 3% rate of SSIs versus 13% for the control group (P=0.015).5 Two retrospective reviews presented in 2014 compared AQUACEL Ag® SURGICAL with sterile gauze in orthopedic and cardiac patients, respectively, and showed that SSI rates dropped from 1.71% to 0.41% (P=0.05) and from 3.4% to 0% (P=0.01).6 In 2016, a retrospective review of 1,173 consecutive patients who underwent a total knee or total hip arthroplasty between 2007 and 2015 by a single surgeon demonstrated a fourfold decrease in acute periprosthetic joint infection with the use of AQUACEL Ag® SURGICAL cover dressing.7 A 2010 Cochrane Review provided a detailed overview of the state of the evidence for silver-containing wound dressings and topical agents in preventing wound infection and healing of wounds.8 The authors identified 26 randomized controlled trials that included 2,066 patients.

Most of these studies were small and poor quality, according to the review. However, of the studies that looked at AQUACEL Ag® SURGICAL versus silver sulfadiazine, the authors found no statistically significant difference in infection or wound healing rates. However, patients reported less pain with AQUACEL Ag® SURGICAL. Similarly, the studies that compared AQUACEL Ag® SURGICAL and povidone-iodine gauze detected no significant difference in infection and wound healing, but there was less pain among patients treated with AQUACEL Ag® SURGICAL."Don't dismiss pain as being irrelevant, because it's not. That's what patients are really focused on, so it's important when you're considering dressings," Dr. Nahabedian said.

Most of Dr. Nahabedian's experience with AQUACEL Ag® SURGICAL is in breast surgery, where infections in the setting of prosthetic breast construction can be devastating and often relate to the vascularity of the skin. He presented some data from a yet unpublished randomized controlled study from the Netherlands that compared AQUACEL Ag® SURGICAL in 99 patients with standard incisional dressings in 120 patients. Overall, SSIs were identified in 7.95% of the AQUACEL Ag® SURGICAL group and 12.5% of controls, although the difference was not statistically significant (P=0.28). Dr. Nahabedian also uses AQUACEL Ag® SURGICAL in some abdominoplasties and incisional hernia repairs. The next step needed is for a randomized controlled trial looking abdominal dressings, he said."We need to reduce the bacterial burden, and AQUACEL Ag® SURGICAL may provide some benefit."

References

  1. Choi JJ, Palaniappa NC, Dallas KB, et al. Use of mesh during ventral hernia repair in clean-contaminated and contaminated cases: outcomes of 33,832 cases. Ann Surg. 2012;255:176-180.
  2. Young PY, Khadaroo RG. Surgical site infections. Surg Clin North Am. 2014;94:1245-1264.
  3. Mangram AJ, Horan TC, Pearson ML, et al. Guideline for prevention of surgical site infection, 1999. Hospital Infection Control Practices Advisory Committee. Infect Control Hosp Epidemiol. 1999;20:250-278.
  4. Walker M, Bowler PG, Cochrane CA. In vitro studies to show sequestration of matrix metalloproteinases by silver-containing wound care products. Ostomy Wound Manage. 2007;53:18-25.
  5. Springer BD, Beaver WB, Griffin WL, et al. Role of surgical dressings in total joint arthroplasty: a randomized controlled trial. Am J Orthop. 2015;44:415-420.
  6. Cai J, Karam JA, Parvizi J, et al. Aquacel surgical dressing reduces the rate of acute PJI following total joint arthroplasty: a case-control study. J Arthroplasty. 2014;29:1098-100. Poster presented at 2014 annual meeting of the Eastern Cardiothoracic Surgical Society. www.convatec.ca/media/1268/ winthropposter.pdf.
  7. Gnosso MJ, Berg A, LaRussa S, et al. Silver-impregnated occlusive dressing reduces rates of acute periprosthetic joint infection after total joint arthroplasty. J Arthroplasty. 2017;32:929-932.8. Storm-Versloot MN, Vos CG, Ubbink DT, et al. Topical silver for preventing wound infection. Cochrane Database Syst Rev. 2010;(3):CD006478.