Modic antibiotic spine therapy (MAST) shows benefit to certain long term back pain sufferers.

A significant number of people with long term lower back pain following a disc herniation (slipped disc) may have a bacterial infection, which may respond to antibiotic treatment. However, the criteria for those who may benefit are quite specific so do not go pestering your GP just yet.

Firstly they must have had a disc herniation. New bone oedema (swelling) visible on MR scans must be present on a follow-up scan 6 to 24 months after the disc herniation diagnosis. This is also called type 1 modic changes (MC1). Around 40% of people with lower back pain have these changes and so do 6% of people without symptoms.

In the study tissue samples were collected from patients undergoing surgery. Nearly half had a microbial infection with most of these being anaerobic (not requiring oxygen to thrive). 80% of the people with this infection developed new MC1 compared to 44% of those with no infection or with only aerobic (requiring oxygen) organisms.

The anaerobic organism found is commonly live on the skin, in hair follicles and in the gums. The authors claim that they were completely sterile through the sample collection procedure and that the absence of several types of organisms went some way in proving that the bacteria were not introduced by them.

The treatment consisted of Amoxicillin Clavulanate. 500mg three times per day for 100 (one hundred) days. 3% of the patients dropped out of the study due to diarrhoea.

Random assignment to either antibiotic treatment or placebo revealed a very highly significant change in those on medication. One year after starting treatment 67% on the antibiotic had lower back pain compared to 94% of those taking placebo placebo group. Constant pain sufferers had reduced from 75% to 20% and from 73% to 67% respectively. Various tests were performed and in all of them the people taking the antibiotic did better than those taking the placebo.

As we can see MAST is not a treatment suitable for everyone with lower back pain and it is certainly not a miracle cure. Taking antibiotics should never be the first choice therapy and due to increasing bacterial resistance their use is generally well controlled and not randomly prescribed. In fact the authors conclude: ”Antibiotics could be considered as a treatment option for this special subgroup of patients with CLBP and Modic type 1 changes after a lumbar disc herniation when all other treatment options have failed. More confirmatory work in other populations and studies on improved protocols as well as the background science should be encouraged.”


Hanne B. Albert, Joan S. Sorensen, Berit Schiott Christensen, Claus Manniche.
Antibiotic treatment in patients with chronic low back pain and vertebral bone edema (Modic type 1 changes): a double-blind randomized clinical controlled trial of efficacy. Eur Spine online February 2013.

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