A good friend of the ARC WM Director, Dr Alistair Stirling, published a revolutionary paper in the Lancet in 2001.[1] His study showed that people with disc herniation in the spine carried certain bacteria in the spinal tissues more often than controls. Infection-related back pain is thought to be associated with rather specific x-ray signs called Modic changes. The putative organism is P. acnes. A previous single RCT has assessed the efficacy of antibiotic treatment in Modic patients.[2] This study reported a significant improvement in outcome in association with the antibiotic therapy.

Replication is a tenet of good scientific practice and a double blind RCT has recently been reported in the BMJ.[3] The authors wanted to see if they could replicate the earlier result. They failed to do so, recording a null finding. However, the trial is not all that large; only 180 patients. Further, one of the two main outcomes was borderline positive. Certainly, any effect is likely to be of modest magnitude and is unlikely to justify three months of continuous high dose antibiotic treatment, as administered in the study. Moreover, there was a much higher incidence of side effects in the intervention group. But what about the underlying hypothesis: is that disproven? Is there a lurking sub-group where infection really is the cause of the back pain? I wonder if we will ever know for sure.

Richard Lilford, ARC WM Director

References:

1. Stirling A, Worthington T, Rafiq M, Lambert PA, Elliott TSJ. Association between sciatica and Propionibacterium acnes. Lancet. 2001; 357: P2024-5.
2. Urquhart DM, Zheng Y, Cheng AC, et al. Could low grade bacterial infection contribute to low back pain? A systematic review. BMC Med. 2015; 13: 13.
3. Bråten LCH, Rolfsen MD, Espeland A, et al. Efficacy of antibiotic treatment in patients with chronic low back pain and Modic changes (the AIM study): double blind, randomised, placebo controlled, multicentre trial. BMJ. 2019; 367: I5654.