Use of antibiotic-loaded polymethylmethacrylate beads for the treatment of extracavitary prosthetic vascular graft infections.

PURPOSE: This study was conducted to assess the efficacy of antibiotic-loaded polymethylmethacrylate (PMMA) beads in the management of lower extremity extracavitary prosthetic arterial graft infection.
METHODS: This was a retrospective review of 34 patients treated for vascular surgical site (VSS) infections involving 36 prosthetic lower extremity arterial bypasses using antibiotic-loaded PMMA beads and culture-specific parenteral antibiotics for 4 to 6 weeks. Sites of graft infection were explored, debrided, and cultured. As determined from the results of Gram's stains of VSS purulence, PMMA powder was polymerized with an antibiotic (vancomycin, daptomycin, or tobramycin/gentamicin, or a combination), molded into a chain of beads, and implanted adjacent to the infected graft after debridement and pulsed-spray antibacterial lavage. All wounds were closed primarily with planned exploration to verify sterilization before a graft preservation or in situ replacement procedure. Treatment outcomes, including wound sterilization, were analyzed based on tissue culture isolates, procedures for persistent infection, and freedom from graft infection.
RESULTS: Cultures isolated 42 pathogens, (32 gram-positive, 9 gram-negative, 1 Candida albicans) with methicillin-resistant Staphylococcus aureus (MRSA) cultured from 16 (44%) of 36 surgical site infections. As determined from the initial operative Gram's stain or a prior culture result, vancomycin PMMA beads were implanted in 29 of 36 VSS infections at the first procedure; daptomycin (n = 4) or tobramycin (n = 3) beads were implanted in the rest. Repeat VSS exploration and culture results led to an average of 2.5 antibiotic bead replacements before definitive treatment. A sterile (no growth on tissue culture) VSS was achieved in 87% of cases before a graft preservation (n = 16) or in-situ replacement of an infected graft (n = 20) procedure. No patient deaths occurred. Early and late limb salvage was 100%. Infection recurred in 4 (11%) VSSs during a mean 23-month follow-up period, one within 3 months owing to unrecognized bowel injury associated with in situ replacement of an aortofemoral graft limb.
CONCLUSION: Antibiotic-loaded PMMA beads may be a useful adjunct in the contemporary surgical management of VSS infection involving a prosthetic graft. Wound sterilization was achieved in most VSSs before graft preservation or an in-situ replacement procedure, including infections caused by MRSA, a pathogen isolated in half of the extracavitary prosthetic graft infections. This preliminary trial shows the potential benefit of this new technique, but further study is required to prove efficacy.