It is hard to believe the report of a group of Danish doctors who found 28 out of 61 (46%) patients undergoing surgery for a herniated lumbar disc to have a bacterial infection in those discs. Just like the idea that stomach ulcers are caused by bacteria seemed preposterous, so does the finding of bacterial infection in patients with low back pain. However, after 10 years of skepticism and ridicule Helicobacter bacteria was recognized as the cause of many stomach ulcers and the doctors who made this discovery were awarded a Nobel Prize. Another recent surprise discovery is that babies are not born sterile but are inhabited by a variety of bacteria which they obviously must have acquired from their mothers while in the uterus. This was established by examining the stool of newborns immediately after birth.
Of the 23 patients with infections 4 had more than one type of bacteria present. The most common type of infection was with Pseudomonas acnes, which does not require oxygen to grow (so called anaerobic bacterium). Most patients with infections had abnormally looking vertebral bones (bone edema), although these abnormalities were not specific, that is they can be present without an infection as well. About 6% of the general population and 35-40% of those with low back pain have these abnormal findings on an MRI scan.
In the second randomized controlled study by Dr. Albert and her colleagues treated 162 patients who had low back pain for more than 6 months, a disc herniation and bone changes on the MRI scan, but who did not undergo surgery. Half of the patients were treated for 100 days with an antibiotic, amoxicillin clavulanate (Bioclavid) and the other half with placebo. The patients taking antibiotics experienced significant improvement for a year compared with those taking placebo. Improvement included the degree of back pain, sleep quality, and disability. Antibiotic caused only mild gastrointestinal side effects.
It is premature to make any definitive conclusions before larger confirmatory studies are conducted. However, in patients with chronic back (and possibly neck) pain as well as bone edema on the MRI scan treatment with an antibiotic should be considered.
