(Originally posted on bcotoronto.com on Oct 20th, 2011)
Recently I’ve been talking about topics that are more about nutrition than chiropractic. So for the next few weeks I’m going to head into specifically chiropractic waters. This week’s topic is Intervertebral Disc Herniations or “Bulging Discs”.
First let’s explore what an intervertebral disc is. The spine is a stack of bones called vertebrae they are shaped like hockey pucks with a ring of bone off the back side. Between each of these bones is a squishy pillow that can best be described as a glob of toothpaste surrounded by layers of plastic wrap. This pillow is the intervertebral disc. It is designed to take the torque and tension we put on our spine through our activities and gravity’s ever present pull.
But no structure is without its flaws. That oral hygiene product-esk gel in the centre of the disc gets pushed back and forth and all around while we are moving, and this movement strains its plastic wrappings. The fibrous layers spread the pressure around the disc very well but can rip and tear under too much strain and eventually become too weak to hold in the gel-like centre. This will make the pillow bulge out and push into areas it does not belong, or “herniate”. This is why a bulging is sometimes called “Degenerative Disc Disease”.
The most common direction for a disc to herniate is backwards and slightly off to one side. This is where the disc is weakest. It is also, unfortunately, where the spinal cord is. This can create pressure on the spinal cord and on the nerves leaving the spine.
The symptoms associated with a disc herniation are pain that travels down a limb and muscular weakness in that limb. Also, local spinal pain can be present. It has been estimated that between 50 and 72% of people suffering from pain like this have disc herniations1. On the other hand, an estimate of 64% has been made for people who have no symptoms at all and have disc herniations seen on medical imaging2. This research has mostly been done on the low back where pain goes down the legs but discs can herniate in the neck as well causing pain down the arms. Discs can herniate in the mid back but this is rare due to the stability of the ribs.
Herniating a disc in the low back is usually associated with activities that combine bending and twisting together, usually with extra weight. So picking up your kids, or furniture, or even taking out the trash can be enough to do this.
When left on their own a herniated disc may continue to degrade to the point where surgery is required but before that point chiropractic therapies are an effective treatment3, 4, 5 and have been shown to decrease the size and even completely resolve the herniations5. If left long enough, permanent damage can occur leaving weakened muscles and areas of skin that have no feeling left. This, of course, is the worst case scenario and is not guaranteed to occur.
In the past, there have been claims that chiropractic treatments cause disc herniations. Early research studies supported this, but when deconstructed the conclusions from this research were flawed. First let`s describe how the research was performed. That ring of bone we talked about hanging off the back side of the hockey puck was removed (This was on bodies donated to science not living people. That would be unethical), which took away all of the structures that normally limit our motion. This leads to the second step. The spine was rotated to such a degree that the discs herniated. The problem with this is that the degree of rotation applied to the spine in the research was much much greater than any living human could ever reach without first fracturing the spine. From these the researchers and the medical community in general said that the small range of rotation used in chiropractic manipulative therapy was dangerous and caused disc herniations. But seeing as the spine is not fractured during chiropractic manipulation it is highly improbable that a herniation could result from an adjustment.
There is a remote chance of experiencing the symptoms of a disc herniation after an adjustment but it is more likely to come from the aggravation of a disc bulge that was not symptomatic than from a new herniation. But this is effectively treated by chiropractic therapies and so is only temporary5.
Bulging discs are not comfortable to live with and very risky to leave alone. So I encourage you to not ignore back or limb pain but to go to a doctor and see what might be the best plan for you.
Thanks for reading,
This is the first time that I’ve provided references for the material that I am using. I will be doing this when I am providing information that is not generally accepted yet. By generally accepted I mean that it can be found in an average textbook on the subject. So whenever there is new evidence or just material that needs to be supported I will be providing a list like this with links to the material for your pleasure and perusal.
- Gilbert et al. Lumbar disk protrusion rates of symptomatic patients using magnetic resonance imaging. Journal of Manipulative and Physiological Therapeutics 2010 33(8):626-9
- Jensen et al. Magnetic resonance imaging of the lumbar spine in people without back pain. New England Journal of Medicine 1994 14;331(2):69-73.
- McMorland et al. Manipulation or microdiskectomy for sciatica? A prospective randomized clinical study. Journal of Manipulative and Physiological Therapeutics 2010 33(8):576-84.
- Santilli V, Beghi E, and Finucci S. Chiropractic manipulation in the treatment of acute back pain and sciatica with disc protrusion: a randomized double-blind clinical trial of active and simulated spinal manipulations. Spine Journal 2006 6(2):131-7.
- BenEliyahu DJ. Magnetic resonance imaging and clinical follow-up: study of 27 patients receiving chiropractic care for cervical and lumbar disc herniations. Journal of Manipulative and Physiological Therapeutics 1996 19(9):597-606.