Monday, July 22, 2013

Antibiotics for the Treatment of Chronic Lower Back Pain: A Paradigm Shift?

Here is an article in the European Spine Journal that at first seems a bit ridiculous. Antibiotics for the management of lower back pain (LBP). Really?

The investigators tested the efficacy of antibiotic treatment in patients with chronic LBP  (>6 months) and Modic type 1 changes (bone edema).
The study was a double-blind randomized controlled trial with 162 patients whose chronic LBP of greater than 6 months duration occurring after a previous disc herniation and who also had bone edema demonstrated (Modic type 1) changes in the vertebrae adjacent to the previous herniation. Patients were randomized to either 100 days of antibiotic treatment (amoxicillin-clavulanate 500 mg tid x 90 days) or placebo and were blindly evaluated at baseline, end of treatment and at 1-year follow-up.
The antibiotic group improved highly statistically significantly on all outcome measures and improvement continued from 100 days follow-up until 1-year follow-up. These included presence of constant back pain, disturbed sleep due to pain, and pain during flexion and extension of the spine.  
Here are some important facts to consider before dismissing the results as a mere placebo effect.

  • First, the study design was rigorous- randomized, prospective, double blind  
  • Second, there are data to suggest that the purported pathogens (P.acnes, staphylococci, corynebacteria) are not present in other spinal disorders, suggesting that these bacteria are not mere colonizers or innocent bystanders
  • Third, P.acnes, secretes proprionic acid, which is capable of dissolving fatty bone marrow and bone, suggesting that biologic plausibility exists for a bacterial cause of back pain 
  • Last, many antibiotics have anti-inflammatory effects, however, amoxicillin-clavulanate, the antibiotic used in this study, typically does not
By no means should all patients with chronic bone receive antibiotics. Further studies are needed to replicate these results. If these findings are valid, a 90 day course of antibiotics for chronic LBP patients with disc herniation and bone edema in the adjacent vertebrae may be warranted.

Sorry about the long blog entry today. 

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