About 60% of 40 year olds have disc degeneration on MRI, and 1 in 3 50 year olds have disc prolapses. But these numbers are in people who don’t even have lower back pain or sciatica. So, there are lots of people with damaged backs who have no pain at all.
Humour me… take a finger and bend it back, right back… Did you get to a point where it’s a bit sore. Now let it go and give it a shake. How is it now? Pain gone? So, pain kicks in often before we damage anything. Now if a healthcare professional bends your finger back, you’ll let them bend it further before you report pain, and if a big hairy wrestler does it, believer me you’ll squeal in pain way sooner.
Let me show you a couple of X-Rays. A construction worker was trollied into the Emergency department screaming in pain. A nail gun injury to his foot –the nail having passed right through the boot and foot. They had to sedate him to cut around the nail that had gone through his foot, but when they did they found the nail had passed between his toes, barely grazing the skin. And yet he had been in agony. In the other X-ray another construction worker had found a sharp lump on the top of his head, gone on holiday for 2 weeks before consulting his doctor and being referred for an X-ray – they found a 2 inch nail in his skull. Clearly another nail gun injury. So, how can one man have agonising pain with no injury at all, and the other have no pain despite a severe injury?
Because all pain is generated in the brain, and the degree of pain we feel is more closely related to fear and perceived threat than it is to actual damage. The strongest predictor of future back pain is past back pain, and the second strongest predictor is the degree of fear of that pain.
The amount of damage has little bearing on the duration of pain.
We tend to think that because we have severe pain, we must have severe damage, but this is certainly not the case, as these examples show. Think of migraine headaches, which can certainly be severe, but not related to any actual damage within the head. Back pain can be the same – severe, but not related to actual severe damage.