What if I Told You That……Discs Heal!?!?

How many times have you had a patient tell you they “blew out a disc” 7 years ago and can’t do anything ever since? How many times have you heard your uncle Bill say the reason he can’t throw a baseball 90mph anymore is because back in his senior year of high school in the glory days he “slipped” his disc and lost his shot at the big leagues? Spinal discs have quite the bad rap for being the cause of significant pain and disability in so many people's lives.

I remember learning quite a bit about disc anatomy and relation to dysfunction while I was in physical therapy school. I learned that discs make up roughly 25% the height of the vertebral column. I learned about the nucleus pulposus and annulus fibrosis of the disc. I learned that repeated spinal flexion under load, especially while twisting, would most definitely increase retro-discal pressure in the lumbar spine and surely cause an injury to the disc. I learned that all herniated discs would likely lead to burning, searing, electrical pain and tingling/numbness down the legs. I learned that the bigger the herniation the worse the pain likely would be.

 

 

The problem with this is that most of it isn’t completely true. Additionally, the idea of a disc being able to heal was never touched upon in my education. For instance, I would like to address the term "slipped disc". Simply put, discs cannot physically slip. They are firmly anchored to the vertebral end plate by exquisitely strong connective tissue which limits their ability to come rocketing out of place like a pinball at the local Chuck E Cheese . In school the disc was never talked about like a normal plastic human tissue that could have the capacity to strengthen with progressive overload, adapt, or even heal. We like to talk about how muscles, nerves, tendons, bones, and even ligaments in some instances can heal with appropriate conservative care and time. In all of my experiences, the disc has been treated like this precious material that if ever compromised or damaged would lead to life long pain and disability. However, I eventually began to wonder "how can my patients with all these disc injuries get so much better with simple physical therapy?" and "how can a single session of repeated motions completely eliminate someone's pain if it were truly a mechanical disc issue at the root of the pain?". With my background as a pain science nerd, I had some pretty good theories on those questions, but I wanted to look at these questions from anatomic and biomechanical viewpoint as this is typically the model our patients come to us ascribing to.

When I went to the research what I found was a little overwhelming and semi-frustrating to not have known previously. There was a plethora of evidence on this very topic. To give a little history about the knowledge of the capacity for discs to heal we have to look all the way back to 1984. In 1984, Guinto et al. first reported a case of lumbar disc regression after conservative treatment.  In the next year, Teplick and Haskin reported 11 cases of spontaneous disc regression. Further studies in following years have repeatedly shown rates of disc regression and healing between 40-100% of the time over the course of 3-40 months. ( see here, here, here, here, here, here, here, and here). I was surprised to find all of this literature due to the fact that in my entire undergrad and graduate school education this was never touched on a single time. I can only assume there are many others in the same boat as me, and I damn well know this isn’t regularly available information to the general population. Not to mention all of the physicians who send me patients scared shitless from disc nocebo talk.

Luckily for us Chiu et al recently conducted a nice systematic review examining the evidence on the ability of intervertebral discs to heal. What they found was quite interesting.

“The rate of spontaneous regression was found to be 96% for disc sequestration, 70% for disc extrusion, 41% for disc protrusion, and 13% for disc bulging. The rate of complete resolution of disc herniation was 43% for sequestrated discs and 15% for extruded discs.”

“Spontaneous regression of herniated disc tissue can occur, and can completely resolve after conservative treatment. Patients with disc extrusion and sequestration had a significantly higher possibility of having spontaneous regression than did those with bulging or protruding discs. Disc sequestration had a significantly higher rate of complete regression than did disc extrusion.”

I have to admit I was still personally quite surprised that the authors of this study were able to in fact find 31 studies that fit their inclusion criteria regarding serial imaging of discs. 31 studies I had never heard of, and wasn’t able to talk about with my patient’s in order to decrease their fear avoidance behaviors. 31 studies I could use as ammo in my patient education gun to shoot down the thoughts and ideas they may have regarding their capacity to heal and ability to engage in recreational activities safely.

 

 

What I found most interesting about the study by Chui was that it appears the larger the disc injury the more likely it is to regress and heal.

As pointed out above:

Sequestration- 96% for regression and 43% complete resolution

Extrusion- 70% for regression and 15% complete resolution

Protrusion- 41%

Bulging- 13%

I have a personal theory that the larger the disc injury the more threatening the body deems it, and therefore the larger the response to heal said injury. Smaller “injuries” such as bulges only a few mm likely are not perceived as dangerous by the nervous system, and therefore unlikely to have a strong healing response mounted. This IS NOT fact or likely even correct, but it makes sense to me in the absence of good evidence to demonstrate why this might be.

I the second half of this article I want to address the likelihood of disc injuries actually being painful. With the invention of advanced imaging techniques we have gotten really really…..really good at finding “pathology”. We can see every little tissue tear, degeneration, disc bulge, etc. and we have fostered an environment where patients seek these imaging procedures out because they are "just positive it will show exactly what is wrong with them". Physicians are scared of lawsuits and/or making a nice chunk of side cash off of imaging which is leading to a gross over utilization. Not to mention the pressure placed on the physician by the demanding patient. Now I don’t want to give the impression that I am anti imaging. I feel that imaging is a vital portion of medical practice and has greatly improved our ability to recognize and treat various conditions. The problem however, is when imaging is abused and results end up in the hands of patients who don’t understand what the results mean for them.

I can’t even begin to count the amount of patients I have seen who are dead set they have no chance of recovery, have to avoid bending, walking, running, exercising, and living life because they are “eaten up with arthritis”,  have “slipped discs”, recreational running “tore up their knees”, and have degenerative disc and joint disease.

However, we hit another evidence based stroke of luck with a study conducted by Hiroaki et al. It was demonstrated in a study of 1211 asymptomatic adults spanning decades from their 20s all the way to their 70s that:

“Most subjects presented with disc bulging (87.6%), which significantly increased with age in terms of frequency, severity, and number of levels. Even most subjects in their 20s had bulging discs, with 73.3% and 78.0% of males and females, respectively. In contrast, few asymptomatic subjects were diagnosed with SCC (5.3%) or increased signal intensity (2.3%). These numbers increased with age, particularly after age 50 years. SCC mainly involved 1 level (58%) or 2 levels (38%), and predominantly occurred at C5–C6 (41%) and C6–C7 (27%).”

I actually have the graph and table of this data printed out in clinic and regularly show it to patients. It’s been my experience that about 2/3 are very interested in the stats and feel much more confident moving forward with exercise. 1/3 tell me they don’t care and they fall in the exception to every rule. You win some you lose some I guess. The following are charts displaying these stats stolen from The Sports Physio A.K.A. Adam Meakins

 

 

 

 

 

Hopefully after reading this you have some new found knowledge, perspective, and confidence to approach your patients and referring professionals with in order to empower our patients pursuits back to full pain free prior levels of function.

 

Thanks again for reading,

Jarod Hall, PT, DPT, CSCS

 

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