title: Treatment of Surgical Site Infection in Posterior Lumbar Interbody Fusion.
abstract: METHODS
  A retrospective observational and case control study.
  
  
  OBJECTIVE
  To identify appropriate treatment options according to the types of surgical site infections (SSI) in instrumented posterior lumbar interbody fusion (PLIF).
  
  
  BACKGROUND
  There has been no agreement or consensus with regard to this matter.
  
  
  METHODS
  Thirty-two consecutive SSIs were included and followed for more than one year. The elapsed time to diagnosis (ETD) according to the type of SSI was analyzed. The treatment options for each type and consequent clinical results were reviewed. The risk factors of removing the implants were analyzed.
  
  
  RESULTS
  There were 6/32 (19%) superficial incisional, 6/32 (19%) deep incisional, and 20/32 (62%) organ/space infection cases (SII, DII, and O/SI, respectively) (p=0.002). ETD was 8.5±2.3 days in SII, 8.7±2.3 days in DII, and 164.5±131.1 days in O/SI (p=0.013). All cases of SII and DII retained implants and were treated by repeated irrigation and secondary closure. Among O/SIs, 10/20 were treated conservatively. Nine out of ten underwent posterior one stage simultaneous revision (POSSR) and in one case, the cage was removed anteriorly. Those who had ETDs longer than 3 months showed a significant risk of implant removal (p=0.008, odds ratio [OR]=40.3). The Oswestry disability index (ODI) improved from 47.3% to 33.8% in SII, from 55.0% to 32.3% in DII, and from 53.4% to 42.1% in O/SI (p=0.002). There was no difference among the three groups (p=0.106); however, there was a partial correlation between ETD and final ODI (r=0.382, p=0.034).
  
  
  CONCLUSIONS
  Latent O/SI was the most common type of SSI in PLIF. In cases of SII and DII, early aggressive wound management and secondary closure was effective and implant removal was not necessary. In some cases of O/SI, implant removal was unavoidable. However, implant removal could be averted by an earlier diagnosis. POSSR was feasible and safe. Functional outcomes were improved; however, disability increased as ETD increased.
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Jung Su
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Dong Ki
authors.initials: DK
authors.lastname: Ahn
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Byung Kwon
authors.initials: BK
authors.lastname: Chang
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea.
authors.forename: Jae Il
authors.initials: JI
authors.lastname: Lee
keywords: Implant removal; Posterior lumbar interbody fusion; Posterior one stage simultaneous revision; Surgical site infection; Treatment