title: Could low grade bacterial infection contribute to low back pain? A systematic review.
abstract: BACKGROUND
  Recently, there has been both immense interest and controversy regarding a randomised, controlled trial which showed antibiotics to be effective in the treatment of chronic low back pain (disc herniation with Modic Type 1 change). While this research has the potential to result in a paradigm shift in the treatment of low back pain, several questions remain unanswered. This systematic review aims to address these questions by examining the role of bacteria in low back pain and the relationship between bacteria and Modic change.
  
  
  METHODS
  We conducted electronic searches of MEDLINE and EMBASE and included studies that examined the relationship between bacteria and back pain or Modic change. Studies were rated based on their methodological quality, a best-evidence synthesis was used to summarise the results, and Bradford Hill's criteria were used to assess the evidence for causation.
  
  
  RESULTS
  Eleven studies were identified. The median (range) age and percentage of female participants was 44.7 (41-46.4) years and 41.5% (27-59%), respectively, and in 7 of the 11 studies participants were diagnosed with disc herniation. Nine studies examined the presence of bacteria in spinal disc material and all identified bacteria, with the pooled estimate of the proportion with positive samples being 34%. Propionibacterium acnes was the most prevalent bacteria, being present in 7 of the 9 studies, with median (minimum, maximum) 45.0% (0-86.0) of samples positive. The best evidence synthesis found moderate evidence for a relationship between the presence of bacteria and both low back pain with disc herniation and Modic Type 1 change with disc herniation. There was modest evidence for a cause-effect relationship.
  
  
  CONCLUSIONS
  We found that bacteria were common in the spinal disc material of people undergoing spinal surgery. There was moderate evidence for a relationship between the presence of bacteria and both low back pain with disc herniation and Modic Type 1 change associated with disc herniation and modest evidence for causation. However, further work is needed to determine whether these organisms are a result of contamination or represent low grade infection of the spine which contributes to chronic low back pain.
authors.affiliation: Department Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Commercial Road, Melbourne, Victoria, 3004, Australia. donna.urquhart@monash.edu.
authors.forename: Donna M
authors.initials: DM
authors.lastname: Urquhart
authors.affiliation: Department Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Commercial Road, Melbourne, Victoria, 3004, Australia. yzhe46@student.monash.edu.
authors.forename: Yiliang
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Commercial Road, Melbourne, Victoria, 3004, Australia. allen.cheng@monash.edu.
authors.forename: Allen C
authors.initials: AC
authors.lastname: Cheng
authors.affiliation: Department of Surgery, Central Clinical School, Monash University, Alfred Centre, Commercial Road, Melbourne, Victoria, 3004, Australia. jeffrey.rosenfeld@monash.edu.|Department of Neurosurgery, Alfred Hospital, Commercial Road, Prahran, Victoria, 3181, Australia. jeffrey.rosenfeld@monash.edu.
authors.forename: Jeffrey V
authors.initials: JV
authors.lastname: Rosenfeld
authors.affiliation: Department of Surgery, Central Clinical School, Monash University, Alfred Centre, Commercial Road, Melbourne, Victoria, 3004, Australia. p.chan@alfred.org.au.|Department of Neurosurgery, Alfred Hospital, Commercial Road, Prahran, Victoria, 3181, Australia. p.chan@alfred.org.au.
authors.forename: Patrick
authors.initials: P
authors.lastname: Chan
authors.affiliation: Department of Surgery, Central Clinical School, Monash University, Alfred Centre, Commercial Road, Melbourne, Victoria, 3004, Australia. s.liew@alfred.org.au.|Department of Orthopaedic Surgery, Alfred Hospital, Commercial Road, Prahran, Victoria, 3181, Australia. s.liew@alfred.org.au.
authors.forename: Susan
authors.initials: S
authors.lastname: Liew
authors.affiliation: Department Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Commercial Road, Melbourne, Victoria, 3004, Australia. monira.hussain@monash.edu.
authors.forename: Sultana Monira
authors.initials: SM
authors.lastname: Hussain
authors.affiliation: Department Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Commercial Road, Melbourne, Victoria, 3004, Australia. flavia.cicuttini@monash.edu.
authors.forename: Flavia M
authors.initials: FM
authors.lastname: Cicuttini
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents; D001424:Bacterial Infections / Q000150:complications* / Q000453:epidemiology; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000382:microbiology*; D008297:Male; D015995:Prevalence
chemical_list: D000900:Anti-Bacterial Agents