Antibiotic Sponge Ineffective at Preventing Surgical Infection
Patients undergoing colorectal surgery are reported to experience an increased incidence of surgical-site infection with the addition of a gentamicin-collagen sponge enclosed at the surgery site. These findings were recently published in the New England Journal of Medicine.
Colon cancer is the fourth most commonly diagnosed cancer in the United States. Each year, approximately 54,000 men and 54,000 women will be diagnosed with colon cancer. Much progress has been made in the early detection and treatment of colon cancer. Screening tests such as colonoscopy allow many cancers to be identified at an early stage and allow for the identification and treatment of precancerous polyps. Advances in surgery, chemotherapy, and targeted therapy have also made important contributions to improved colon cancer survival; it is estimated that there are more than 700,000 colon cancer survivors in the United States today.
In patients with potentially curable colon cancer, a properly performed surgical operation is essential for optimal results. In the majority of such cases, operative intervention involves a resection (removal) of the primary cancer and regional lymph nodes, along with the removal of sections on both sides of the normal bowel. Conventional surgery (open colectomy) for colon cancer requires surgeons to create a large opening in the abdomen in order to reach the cancer. Laparoscopic surgery, also called minimally invasive surgery, allows surgeons to do procedures by making only a few small incisions in the abdomen. Infection is a potential complication from any surgery and has a particularly high incidence in colorectal surgery. Strategies to reduce infection after surgery are ongoing.
The gentamicin-collagen sponge is one strategy under investigation that could potentially reduce infection. The antibiotic sponge allows high gentamicin concentrations at the surgical site and biodegrades within a few days. In a previous randomized European study, the gentamicin-collagen sponge placed during colorectal surgery decreased infections at the site of surgery by 70%. In order to confirm these findings, researchers recently conducted a larger randomized trial evaluating whether or not this antibiotic sponge used during colorectal surgery reduced surgery-related infections.
In this Phase III study, researchers selected 602 patients undergoing colorectal surgery to either have two gentamicin-collagen sponges placed strategically inside the surgical site prior to closing or to receive no sponges. Of the 602 patients, 51% had colorectal cancer and the other 49% were undergoing colorectal surgery due to diverticultis or inflammatory bowel disease.
- 30% of patients who received sponges during surgery experienced surgical-site infections compared with 31% in the control group who did not receive sponges (P=0.01).
- Superficial surgical site infections were also experienced significantly more in the group receiving the antibiotic sponges compared with no sponges; however, deep infections did not differ significantly.
- Office and emergency room visits due to wound complications were also significantly higher in the antibiotic sponge group.
The findings of this study were unexpected based on previous trial data. Although the study was not powered to determine why the antibiotic sponge failed, the researchers postulated that the antibiotic may have dissipated too quickly and/or the sponge may have slowed down wound closure. Studies to evaluate alternative strategies to improve surgery-related infections are warranted.
 Bennett-Guerrero E, Pappas TN, Koltun WA, et al. Gentamicin–collagen sponge for infection prophylaxis in colorectal surgery. New England Journal of Medicine. [early online publication]. August 4, 2010.
 HJ Rutten, PH NijhuisPrevention of wound infection in elective colorectal surgery by local application of a gentamicin-containing collagen sponge. Eur J Surg Suppl. 1997;578:31-35.
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