Often blamed for back and leg pain the humble intervertebral disc is often the misunderstood villain of the back. To figure out how to heal them, first we need to understand how they work and what might be going wrong.

What is a disc?

Your discs are the shock absorbers of the spine, and like the shock absorbers in your car, they utilise fluid to absorb forces created whilst we move. They have a gel like fluid centre enclosed by an outer fibrous casing (to stop the fluid from escaping!). They sit between each bone of the spine, and take the weight of the body so the joints are free to move freely without carrying any weight. Think of the disc like a water filled balloon. The bones balance and wobble about on top of these discs giving the spine its flexibility.

How does the disc slip or prolapse?

Sometimes the fibrous casing of the disc becomes weakened so the pressure of the fluid pushes outwards causing a bulge, a disc prolapse. The prolapse can be anything from a tiny bulge to a big protrusion and even to a burst prolapse where some of the fluid centre leaks out.

Not all disc prolapses are painful

Although disc prolapses have certainly been found in people with awful back pain, the medical community have been questioning whether disc prolapses are the culprit. You can see the problem, someone comes in with back pain, they get a scan that shows a disc prolapse, so disc prolapse = back pain.  However, we weren’t scanning people who didn’t have back pain.

Que the scanning of people with no back pain at all, and guess what we found…..lots of disc prolapses! We had been assuming disc prolapses were causing pain and treating them as the culprit, even operating on them, which helped some people but certainly not all. We now know that disc bulges are a normal MRI finding, increasing as we get older seen in 50% of those over 40yrs and 60% of people over 60yrs.

So what is causing the pain?

There is no doubt that some disc prolapses are associated with pain, numbness and tingling in the back and leg.  These are prolapses that have burst, leaking a small amount of gel fluid, irritating the nerve right next to it and can cause back and leg pain. Interestingly painful disc prolapses tend to decrease whilst we get older. Although we see more disc prolapses as we age these are far less likely to leak fluid as our disc gradually dry out with age.

What treatment works?

Generally, movement is best, so taking some painkillers such as paracetamol to get you moving again really helps. Keep doing normal daily activities if you can, as much as the pain allows. Short periods of rest and relaxation can also be helpful, particularly lying on your back with your legs on something so your hips and knees are at 90 degrees.

Manual therapy can really help relax the muscles of the spine and reduce the pain. Medical acupuncture can also help to relieve pain

Can disc prolapses heal?

Yes they can! Our bodies are incredibly good at fixing stuff, and usually it takes about 6 weeks for the pain to go away. Even when the pain has gone, you may still have a disc prolapse but it won’t be painful because your body will have fixed the leak, stopping the gel fluid centre from leaking out and irritating the nerve. Most importantly, as the pain diminishes and disappears, is to keep the back mobile, developing your flexibility so the disc casing builds strength, preventing it from happening again.

References:

InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Slipped disc: Non-surgical treatment options. [Updated 2020 Apr 9].

W. Brinjikji, P.H. Luetmer, et al. (2015) Systematic Literature Review of Imaging Features of Spinal Degradation in Asymptomatic Populations. AJNR Am J Neuroradiol. 36(4): 811–816