Delayed infection after elective spinal instrumentation and fusion. A retrospective analysis of eight cases.

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.