Delayed Infection After Elective Spinal Instrumentation and Fusion

STUDY DESIGN: A retrospective analysis of eight cases of delayed spinal infection after elective posterior or combined anterior and posterior spinal instrumentation and fusion. OBJECTIVES: These cases are reviewed to identify risk factors for delayed spinal infection after elective instrumentation and to describe the treatment of this complication. SUMMARY OF BACKGROUND DATA: Delayed spinal infection after elective spinal instrumentation and fusion is uncommon. This diagnosis is frequently difficult. METHODS: Five cases seen in the senior author's practice and three referral cases are reviewed. RESULTS: Of these eight cases, the organisms were Staphylococcus epidermidis in six cases, Propionibacterium acnes in one cases, and in the final patient, all intraoperative cultures were negative. Clinical presentations were variable; however, all patients reported back pain. Seven patients had elevated erythrocyte sedimentation rates, averaging 57 mm/hour. Only two had elevated white blood cell counts. No distant foci of infection were identified in any patient. Five-patients were found to have at least one pseudarthrosis. All patients were treated with debridement, instrumentation removal, and primary wound closure over drains followed by a minimum 6-week course of culture-directed postoperative antibiotics. At an average follow-up of 18 months, no patient has evidence of infection. CONCLUSIONS: The diagnosis of delayed infection after elective spinal instrumentation and fusion requires a high index of suspicion. These infections may have been caused by intraoperative inoculation. All patients were successfully treated with debridement, instrumentation removal, and culture-directed postoperative antibiotics.