title: Management of late (>1 y) deep infection after spinal fusion: a retrospective cohort study.
abstract: 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.
  
  
  METHODS
  
  
  
  METHODS
  retrospective comparative study.
authors.affiliation: Musculoskeletal Research Center, Orthopedics Institute, Children's Hospital Colorado, Aurora, CO.
authors.forename: Sumeet
authors.initials: S
authors.lastname: Garg
authors.forename: Jaren
authors.initials: J
authors.lastname: LaGreca
authors.forename: Mark
authors.initials: M
authors.lastname: Hotchkiss
authors.forename: Mark
authors.initials: M
authors.lastname: Erickson
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002648:Child; D003646:Debridement; D020878:Device Removal; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000150:complications / Q000628:therapy*; D006801:Humans; D016268:Internal Fixators / Q000009:adverse effects*; D008297:Male; D011425:Propionibacterium acnes; D016459:Prosthesis-Related Infections / Q000382:microbiology / Q000628:therapy*; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000009:adverse effects* / Q000295:instrumentation; D013530:Surgical Wound Infection / Q000382:microbiology / Q000628:therapy*
chemical_list: D000900:Anti-Bacterial Agents