This study evaluated the diagnosis, treatment and related results for cases with a deep infection after instrumented posterior fusion.

Among the 306 cases of posterior instrumented spinal fusion, Seventeen cases who developed deep infection were reviewed retrospectively.

The incidence of deep infections was 5.6% and the mean age of the cases with a deep infection was 55 years old. Nine out of 17 cases had the preoperative risk factors such as old age, diabetes, malnutrition, obesity, etc. The mean duration to diagnosis of a postoperative infection was 12.9 days (4-8 days). The clinical manifestations were fever, night pain and abscess drainage. In all cases, the value of the WBC, ESR and CRP were elevated. All cases were treated surgically as soon as possible with abscess drainage, debridement and the insertion of antibiotics-mixed cement beads without the removal of the instrument. The most common bacterial organisms were Coagulase negative Staphylococcus aureus in 11 cases. Vancomycin was used as the antibiotic. During the follow-up period, 2 cases were treated with the removal of the instruments due to metal failure and a delayed deep infection with loosening. The average follow-up was 32 months (12-56 months). 15 cases were controlled successfully without needing to remove the instruments and without complications.

The meticulous care for a deep infection after posterior instrumented spinal fusion is essential. Favorable results can be achieved by surgery with drainage, debridement, and the insertion of antibiotics-mixed cement beads along with systemic antibiotics as soon as possible without removing the instruments.