What does the research show?
Several studies have shown that large extruded discs appear to have the greatest tendency to dramatically decrease in size and resolve with conservative management or even if left completely alone (source).
Here is an example of a large disc on an mri scan that has healed over a 12 month period
So.. How much do discs improve?
How long do they take to heal?
Does it depend on what direction my disc has bulged?
One paper looked at a large group of patients with large disc prolapses over a 2 year period by repeatedly scanning them and monitoring what was happening to their disc prolapses over time. A large proportion of these patients had severe sciatica initially but then began to experience less pain as time went on despite having a large disc herniation on their scan. They found that 83% of the people they studied had a complete and sustained recovery when followed up two years later with only four patients requiring surgery! On average, over the two years, the size of the disc protrusions were reduced by 64% (source). It didn't matter if your disc was bulged in the middle (centrally) or out to the side (far laterally) as the results found were both similar.
Another paper found that 38% of all the disc prolapses they observed became smaller in size when left completely alone. Among their results they found that more specifically, extruded disc 'fragments' resolved 100% of the time and disc 'herniation's' resolved in 83% of cases! They proposed that the reasons for disc fragments doing so remarkably well was that they have clear disc material that extrudes and actually detaches itself from the disc so it no longer receives nutrients and supplies. This leads to an inflammatory response that begins reabsorbing the disc fragment. Over a six month period most disc protrusions were on average 1/3 of their original size (source).
Can we predict what will happen?
Where early improvement is seen then the outlook is far better (source).
If there is no improvement at 1 year then resolution is less likely to happen on its own (source) & (source).
Does this apply to all discs?
Unfortunately it is not as simple as that.....
Just because disc prolapses have been shown to improve without surgery, it does not mean you should ignore your disc prolapse completely! Some can get worse and lead to permanent problems. If you have been diagnosed with a disc prolapse or even if you just have back pain then there are a number of things to look out for as the following warning signs..... (source).
Saddle anaesthesia (loss of feeling between the legs, numbness in or around your back passage or genitals)
Bladder disturbance (inability to urinate or difficulty initiating urination, loss of sensation when passing urine, inability to stop of control urination, loss of feeling your bladder is full)
Bowel disturbance (inability to stop a bowel movement, constipation, numbness when passing a bowel movement)
Sexual problems (inability to achieve an erection or ejaculate, loss of sensation during intercourse)
Nerve root pain (worsening pain into one of both legs with weakness in your legs)
All of the previous signs are relatively rare. The vast majority of people are very unlikely to have any of the above symptoms and it would be perfectly reasonable to just leave things alone and see how it goes. Benson et al (source) states that if there is evidence of clinical improvement, massive disc prolapses do not appear to carry a risk of major nerve damage or cauda equina syndrome.
(This blog is not a substitute for medical advice, if you experience any of the above then you must seek prompt medical advice)
As always, we continue to prioritise educating and reassuring our patients.
Thanks for reading