"Disc bulge"... a phrase that has probably created more damage than the injury itself. How many people hear that term and automatically think "I'm never going to recover" or "my back is never going to be the same"? As Physiotherapists we have the continual and tough challenge of coaching our patients through recovery after a back injury and encouraging them to believe they can and they will get better.
Even though disc herniations are reported to be one of the highest contributors to back pain in the community, "60% to 90% of lumbar disc herniations can be successfully treated with a conservative approach" (Chiu, et al., 2001, p. 185). That is some good news!
For many people, medical imaging such as MRI becomes a part of their evaluation at some stage. There is constant debate regarding the clinical necessity of imaging to confirm diagnosis, as well as the potentially harmful effect it may have (mentally). We often land up referring for an MRI to confirm clinical diagnosis but, interestingly, we don't often refer for a repeat MRI when people recovery. Nevertheless, we have countless studies showing that: people can have disc bulges and be painfree, others can have pain without disc pathology, and some will improve despite MRI imaging remaining the same. While MRI remains a excellent assessment tool, it unfortunately carries the burden of giving patients a beautiful mental image of 'how bad their injury is' and can contribute to negative thoughts about recovery and prognosis.
I've recently read this brilliant article that I wish to share with you.
In 2014, Chiu and colleagues conducted a systematic review to determine the probability of a spontaneous disc regression. The aim of the systematic review was to investigate the probability of disc herniation regression and complete resolution. Their search only included studies that had used conservative treatment .
NOMENCLATURE for disc herniations
In this study, disc herniations were classified using the terms from the 'Combined Task Forces', a committee formed by the North American Spine Society, American Society of Spine Radiology, and American Society of Neurobiology. In 1995, they released a classification that included the following descriptions:
- focal protrusion
- broad-based protrusion
Based on this classification one can see that the word bulge can't be used to describe all problems and the word herniation is actually preferred. "Disc herniation is present if there is localized displacement of disc material, and not simply outward overlapping, as is the case with some types of bulging" (Fardon & Milette, 2001, p.E100).
"A disc is “protruded,” if the greatest plane, in any direction, between the edges of the disc material beyond the disc space is less than the distance between the edges of the base, when measured in the same plane. Protrusions may be “focal” or “broad-based.” (Fardon & Milette, 2001, p.E100).
"The term “extruded” is consistent with the lay language meaning of material forced from one domain to another through an aperture. Extruded disc material that has no continuity with the disc of origin may be further characterized as “sequestrated.” (Fardon & Milette, 2001, p.E100-E101).
Based on my online searching and also to the knowledge of these researchers, this was the first systematic review on this topic. And this is what they found....
The probability of a spontaneous regression was:
- 96% for disc sequestrations.
- 70% for disc extrusions.
- 41% for focal protrusions.
- 13% for disc bulges.
What this means is that the higher the grade of disc herniation, the higher the rate of spontaneous regression.
How does regression occur?
The authors propose three hypotheses as to how regression occurs:
- The herniation retracts to its original position (more likely to occur in a bulge or focal protrusion).
- The herniation is reduced through a dehydration process.
- Disc herniations into the epidural space have a higher probability of triggering an inflammatory response. The result of this is often neovascularisation and absorption of disc material through phagocytosis and enzyme dehydration.
Correlation between disc herniation regression & clinical improvement
The correlation between disc regression and improvement of clinical outcomes is a controversial topic, because there are so many variables that influence recovery besides the size of the disc herniation. The sole variable of "disc herniation size" or "disc herniation regression" cannot predict clinical outcomes. But this study does offer some very encouraging statistics to tell us that the larger or more severe herniations often have a higher chance of spontaneous recovery.
So the next time you have a patient presents with a more severe disc herniation, you can use the outcome of this systematic review to encourage them (an yourselves) that there is a good probability that spontaneous regression will occur, and that just because the herniation is big on the MRI, doesn't mean they can't recovery.
Chiu, C. C., Chuang, T. Y., Chang, K. H., Wu, C. H., Lin, P. W., & Hsu, W. Y. (2015). The probability of spontaneous regression of lumbar herniated disc: a systematic review. Clinical rehabilitation, 29(2), 184-195.
Fardon, D. F., & Milette, P. C. (2001). Nomenclature and classification of lumbar disc pathology: recommendations of the combined task forces of the North American Spine Society, American Society of Spine Radiology, and American Society of Neuroradiology. Spine, 26(5), E93-E113.