Given ground-breaking new research into the role that infection may play in significant numbers of low back pain cases, this month Jason looks back through the LP&E files to a case that was once thought an aberration, but which now has more relevance than ever. Put the kettle on, draw up your favourite armchair, and read the story of 'Disc-o Fever'.

Those were the days my friend....

Those of you of a certain age may remember with fondness the late Sunday evening ITV entertainment schedule in the 80s; the weekend's last redoubt before the inevitable return to school the next morning. 'The Professionals', 'Spitting image' and 'Tales of the Unexpected', all staples of the only ITV channel available at the time but now, in a 24/7 age of digital desiderata, positively anachronistic in style and content.

It's not only televisual 'bread and circuses' that adapt to scientific discovery and technological innovation however, and it seems the findings of recent orthopaedic research may be pushing a paradigm shift with regard to long-held views on the causes of low-back pain. The new idea on the role that infection plays in the creation and/or perpetuation of back pain reminded me of a personal 'tale-of-the-unexpected' from the annals of LP&E and one which I'll relate here. We'll start with a short anatomy lesson....

Intervertebral discs

Each backbone, or vertebra, has a disc separating it from the next backbone above and below. The disc effectively holds the bones apart, acts as a shock absorber, and is responsible in part for nourishing the bones either side. The disc is not solid but has an outer tough ring made of cartilage, the 'annulus', and an inner squishy substance made primarily of water called the 'nucleus pulposus'.

In response to movement backwards and forwards the nucleus moves inside the annulus like a bubble in a spirit level when offset beyond a horizontal plane. Although a simplified explanation if you bend and twist too much forwards the nucleus wears channels through the back of the annulus. This can make the latter bulge and in severe cases tear, effectively spilling the nuclear contents against adjacent structures such as spinal nerves.

Bulging or pressure against the nerves and other pain-sensitive areas is what causes pins and needles, numbness and the pain that you find in sciatica or brachalgia, depending on whether it's a lower back or neck disc respectively. This the 'mechanical explanation' of some types of back pain.

An alternative explanation

While not rejecting the traditional mechanical causes of back pain the new research suggests that a simple bacteria called Propionibacterium acnes (Pa), normally responsible for contributing to acne, can enter the body through entry points such a gum recession. Once there it can travel in the bloodstream and colonise healing tissue such as disc injuries. The authors suggest that infection with Pa can effectively extend the period of healing indefinitely and the swelling and micro-fractures in vertebrae created can be the direct cause of the development of chronic lower back pain.

Now it is highly unusual (in my opinion) for medics to support research evidence when they stand to lose out financially in private work. Yet the research has been heralded as being so revolutionary that eminent surgeons deem it worthy of entry for the Nobel Prize for Medicine. High praise indeed.

Back to the future

Reading the story this week took me back to a case from seven years ago that I'd seen in another town. 'X' booked in to see me with some middle-to-upper back pain that was referring to their shoulder. As an aside X also related that they had recently been diagnosed with osteoarthritis in the hips by their GP as they'd found their legs "...weren't going as well just recently".

The more I questioned X the more alarm bells rang in my head thinking they could be that one-in-a-thousand cases with a 'red flag pathology', i.e. a severe problem requiring immediate investigation. From what X related their diagnosis of OA had also been given without an X-ray of the hips. On examination X's hip flexibility would have put Mister Fantastic to shame and clearly the shoulder pain was also a red herring.

I personally felt X had spinal cord compression, and that something was pushing into it and stopping most of the messages getting to their legs from the brain. I took the chance of being safe rather than sorry and referred X straight away to the local hospital A&E dept with an accompanying letter requesting immediate MRI scan and my reasoning for doing so.

The best £27 consultation in the world

Six weeks passed and I wondered what had happened to X. I always ask patients to keep in touch and let me know the result of investigations if they're not booked in for another appointment. It's a shame that few actually do so. One day there was a message left in the clinic communication book. X had contacted to say the hospital had indeed scanned the problem area and they had in fact been suffering from cord compression.

This had required immediate spinal decompressive surgery the day that I saw them six weeks previous to relieve the pressure. The surgeon had also said that if it had not been caught at that time the tissue in X's cord would have started to die, and as a consequence they would have been permanently left without the use of their legs and doubly incontinent.

The cause, dear reader? An infected disc at the 7th thoracic level which had swollen to twice its normal size. I'd never heard of it in any of the text books I used through my training or seen this as an explanation since, so you can imagine this week's findings were somewhat of a Eureka moment personally.

It's a story that's always stayed with me as it's the one I always relate to patients who ask what the difference is between a an experienced Chartered Physiotherapist and someone with less professional expertise and qualifications working in the same field.

The answer, it seems, can potentially be the difference between being able to control your bladder and bowel and also the ability to walk to the toilet unaided in the first instance.

Thanks again for reading, Jason