Do Discs Heal?

So, you’ve hurt your back; doctor says you need an MRI… MRI says you have disc bulge/herniation/protrusion blah blah blah. Now What? Will you be ok? Will it heal? When you herniate a lumbar intervertebral disc you can quickly experience pain in your lower back that can even radiate down into your leg(s). It’s a scary experience that is usually initiated by a relatively innocuous event such as picking up your kid or bending over to pick up the newspaper. There have been many journals in the past and relative present that demonstrates, discs do in fact, have the ability to heal and resolve on their very own.

Intervertebral discs, are fibrocartilaginous structures situated between vertebrae. Discs are designed to absorb load and disperse it throughout the spine. When they’re injured their ability to distribute load is hindered. Disc herniations are not necessarily indicative of functional loss or pain but with good clinical assessment they absolutely can be relevant pain generators and treated. The good news is that disc herniation’s can be reabsorbed and “heal” to a certain extent.

In 2006 an article came out in SPINE that focused on the determinants of spontaneous disc resorption by Autio et al. They examined 160 patients with lumbar disc herniation’s presenting with unilateral sciatica for 3-28 weeks. They were scanned initially, at two months, and then at 1 year. What they found was that there was a significant recession of disc herniation at 2 months and even more of a recession at 1 year.

hnp healing

Baseline (A), 2-month (B), and 1-year scans (C).

They also determined that the larger the herniation, the quicker the resorption, ages 41-50 are associated with a higher resorption rate, and clinical improvement in leg pain and dysfunction were found with herniation recession.

A systematic review by Chiu et al. in 2015 searched through all the data to establish the probability of spontaneous regression of lumbar disc herniations. They showed that the larger the herniation, the quicker it regressed, which is similar to the results shown the previously discussed paper. They examined four types of disc herniations and found that sequestrated, extrusions, protrusions, and disc bulging all had the ability to regress. The percent of regression for each was …

96% of sequestrated discs

70% of extruded discs

41% protruded discs

13% bulging discs

They also found that 43% of sequestrations and 15% of all extrusions completely resolved. There are a few reasons as to how it is believed that these disc injuries resolve spontaneously.

It is believed that larger herniations regress quicker due to it being closer to the outer annulus and epidural space. When the herniation is exposed to the outer annulus and epidural space it’s subjected to systemic circulation. There are two mechanisms for disc resorption. The first is dehydration. When a disc herniates there is a release of proteoglycan molecules that begin to swell. Over time, these proteoglycans degrade and cause the herniated disc material to dehydrate, reducing the swelling. The second is an immune response that leads to inflammation and neovascularization for phagocytosis of the disc material. Macrophages in the area of the herniation leads to an increase of inflammatory cytokines. These cytokines spark new vascularization at the outer annulus. This all leads to healing and herniation regression.

With all this said… who cares? Well, your patient should and they should be educated about this. It’s important to understand this concept because it can allow your patient to make an educated decision on whether or not conservative care or surgery is the right option for them. If the disc “heals” then why have surgery on it? If there is still pain after surgery, is it the disc?

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