DELAYED INFECTION AFTER ELECTIVE SPINAL INSTRUMENTATION AND FUSION - A RETROSPECTIVE ANALYSIS OF 8 CASES

Study Design. A retrospective analysis of eight cases of delayed spina l infection after elective posterior or combined anterior and posterio r spinal instrumentation and fusion. Objectives. These cases are revie wed to identify risk factors for delayed spinal infection after electi ve instrumentation and to describe the treatment of this complication. Summary of Background Data. Delayed spinal infection after elective s pinal instrumentation and fusion is uncommon. This diagnosis is freque ntly difficult. Methods. Five cases seen in the senior author's practi ce and three referral cases are reviewed. Results. Of these eight case s, the organisms were Staphylococcus epidermidis in six cases, Propion ibacterium acnes in one case, and in the final patient, all intraopera tive cultures were negative. Clinical presentations were variable; how ever, all patients reported back pain. Seven patients had elevated ery throcyte sedimentation rates, averaging 57 mm/hour. Only two had eleva ted white blood cell counts. No distant foci of infection were identif ied in any patient. Five patients were found to have at least one pseu darthrosis. All patients were treated with debridement, instrumentatio n removal, and primary wound closure over drains followed by a minimum 6-week course of culture-directed postoperative antibiotics. At an av erage follow-up of 18 months, no patient has evidence of infection. Co nclusions. The diagnosis of delayed infection after elective spinal in strumentation and fusion requires a high index of suspicion. These inf ections may have been caused by intraoperative inoculation. Ail patien ts were successfully treated with debridement, instrumentation removal , and culture-directed postoperative antibiotics.