Abstract
Antibiotic polymethylmethacrylate (PMMA) beads are known as an effective drug delivery system for local antibiotic therapy in bone and soft tissue infections. Over the years it has become an efficient method to treat osteomyelitis and other infections in orthopaedic surgery. Whilst this method has gained popularity primarily in infected arthroplasty, trauma and chronic osteomyelitis, its application in spine surgery is less known.
Methods: From 1997 to 2000 we have followed prospectively all patients who developed severe purulent wound infection following various types of instrumented spine fusion. Any patient, who had the typical presentation of surgical wound infection was enrolled into the study. Revision consisted of radical debridement of all necrotic tissue from the surgical wound, jet irrigation with saline and application of antibiotic contained PMMA beads. Primary closure over a suction drain was done in all cases and the patient was treated with parenteral antibiotic therapy. Following first revision, patients were treated with broad-spectrum parenteral antibiotic therapy, which was converted to culture-sensitive antibiotic. Suction drains were removed when the output was less than 50cc/24hr. Patients were returned for a second revision when local and systemic parameters showed no evidence of active infection.
This revision consisted of PMMA bead removal, debridement as necessary and irrigation. Primary closure over a suction drain was performed in all cases. No hardware removal was done in any of the cases. Follow up studies included radiographs and gallium bone scan.
Results: There were five patients in the study group. Of these, two had posterior spinal fusion for trauma; the remaining three had fusion for a various etiologies (tumor, corrective osteotomy in ankylosing spondylitis and lumbar instability). Causative organism was staphylococcus aureous (2 patients) and MRSA (3 patients). Mean interval from primary surgery to the first revision was 12 days and 19 days until the second revision. None of the patients had a third revision. There was no evidence for exacerbation of the infectious disease during follow up nor any pain or other signs which could mark the beginning of chronic osteomyelitis. No systemic or local complications related to the surgical technique or the PMMA beads were noted during the period between revisions. Galium scan was performed in only three of the five patients for a different reason. Scan results were negative in all three.
Conclusion: Two-stage revision surgery with PMMA antibiotic beads in a purulent surgical wound infection following spinal fusion, is a highly efficient method. This approach can assure proper healing of the surgical wound with no need for instrumentation removal or prolonged secondary healing of the surgical
The abstracts were prepared by Orah Naor. Correspondence should be addressed to him at the Israel Orthopaedic Association, PO Box 7845, Haifa 31074, Israel.
