title: Sterility of posterior elements of the spine in posterior correction surgery.
abstract: METHODS
  Prospective clinical series.
  
  
  OBJECTIVE
  To investigate the sterility of the posterior elements of the spine during posterior correction surgery.
  
  
  BACKGROUND
  Bacterial growth in the operating field is considered one of the causes of surgical-site infection.
  
  
  METHODS
  A total of 80 consecutive patients (mean age = 19.5 years) who underwent posterior correction surgery for spinal deformities were included in the study. During surgery, specimens for bacterial culture were obtained by swabs from (1) the skin after cleansing using povidone-iodine scrub solution but before draping, (2) laminae immediately after exposure, (3) laminae immediately after screw placement, (4) laminae immediately before wound closure, (5) a small piece of bone obtained from the spinous process immediately after exposure and placed on a sterile dish during surgery as a control, kept covered, and (6) a similar sample as (5), kept uncovered. The culture was conducted on both blood agar and Gifu anaerobic medium agar plates.
  
  
  RESULTS
  No patient developed surgical-site infection. The culture was positive in specimen (S) 1 in 25 patients (31.3%), S2 in 20 (25%), S3 in 25 (31.3%), S4 in 26 (32.5%), S5 in 6 (7.5%), and S6 in 7 (8.8%). Bacterial species included Propionibacterium acnes in 15 specimens, Propionibacterium species in 9, and others in 10. Of the 25 patients with a positive culture in S1 and 55 patients without, 22 (88%) and 26 (47.3%), respectively, demonstrated a positive culture in specimens obtained during surgery.
  
  
  CONCLUSIONS
  The culture was more frequently positive in specimens obtained immediately before wound closure than in those harvested immediately after exposure and isolated from the surgical field. The results suggest that bacterial contamination of the operating field may originate from the skin of the patient during surgery.
authors.affiliation: Department of Orthopaedic Surgery, Keio University, Tokyo, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shiono
authors.forename: Kota
authors.initials: K
authors.lastname: Watanabe
authors.forename: Naobumi
authors.initials: N
authors.lastname: Hosogane
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuji
authors.forename: Ken
authors.initials: K
authors.lastname: Ishii
authors.forename: Masaya
authors.initials: M
authors.lastname: Nakamura
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiba
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D011424:Propionibacterium / Q000302:isolation & purification*; D011446:Prospective Studies; D013131:Spine / Q000002:abnormalities / Q000382:microbiology* / Q000601:surgery; D013530:Surgical Wound Infection / Q000382:microbiology*