Background: The incidence of late infection published in the literature varies from 1% to 12% with varying definition of late infection (range, 3 mo to 1 y). Current evidence suggests implant removal and antibiotic therapy is necessary to clear these infections. A high incidence of late (>1 y) deep infection after instrumented spinal fusion was identified at our institution. We sought to evaluate the efficacy of our management of these patients.
Methods: A total of 1390 patients underwent instrumented spinal fusion from 2000 to 2009. Forty-two patients developed deep infection >1 year after index procedure (3%) and had surgical debridement. Clinical records and microbiology reports were reviewed for details of operative and postoperative management.
Results: Advanced imaging was only obtained in 6 patients (5 computed tomography, 1 magnetic resonance imaging). Offending organisms were identified in 39/42 patients, 27 of these grew Propionibacterium acnes. P. acnes grew in culture at a median of 6 days (range, 3 to 10 d), significantly longer than all other organisms, which grew in a median of 1 day (range, 0 to 8 d) (P<0.001). Implants were removed at the index hospitalization in 41 patients. Implant retention was attempted in 1 patient and failed. Primary closure was carried out in 37 patients; the remainder had undergone multiple debridements (4 planned, 1 unplanned). VAC closure was utilized in 2 patients. All patients were treated with organism-specific intravenous antibiotics and transitioned to oral antibiotics on average in 34 days (range, 2 to 186 d). Total length of antibiotic therapy was an average of 141 days (range, 34 to 413 d).
Conclusions: P. acnes was the most common organism identified and took nearly 1 week to grow in culture. Treatment is generally successful with thorough debridement, removal of implants, and antibiotic treatment.
Level of Evidence: Level III: retrospective comparative study.
Musculoskeletal Research Center, Orthopedics Institute, Children’s Hospital Colorado, Aurora, CO
This study was approved by the Colorado Multiple Institutional Review Board.
No sources of funding were received.
The authors declare no conflicts of interest.
Reprints: Sumeet Garg, MD, Children’s Hospital Colorado, 13123 East 16th Avenue, P.O. Box 060, Aurora, CO 80045. E-mail: firstname.lastname@example.org.