Have you ever wondered how our animal counterparts (non-human primates) fair with degenerative disc disease?
Probably not, I am guessing, but as a researcher and Nanaimo Chiropractor, I am always looking for answers for this very common condition.
Degenerative disc disease is a condition of the intervertebral disc. This is the break down of the shock absorbing structures between the vertebrae in the spine. The discs are supposed to make up about a third of the total spine height but as they degenerate, they lose height. They lose height because they are unable to sustain the load. To learn more about this, you can read more here. They are unique structures made up of concentric fibrous sheets containing a gelatinous centre. Radial tears contribute mostly to the problem.
There are two main competing theories that contribute to the onset of degeneration. One research camp thinks it is the genetic make-up of discs that play a big part why some people’s discs break down. These researchers believe it is the genes that are either strong or weak. On the other hand (which has more theoretical followers) is the camp that believes it is how they are used and this contributes to the onset. That is, if you overload them in the wrong directions, they will break down and lead to progressive height loss. This camp holds more weight in the literature as we even see degeneration happen when they are punctured with a small needle. So as for nature vs. nurture, nurture currently holds more water in the literature.
So when it comes to nurture, one of the factors is how we behave as humans, and specifically, could the way we walk play a role in the development of this condition? Or more specifically, could the walking of non-human primates provide treatment clues?
In a review paper by Robert Jurmain titled: Degenerative joint disease in African great apes: an evolutionary perspective, he looked at 12,479 joint surfaces for determination of spinal osteoarthritis ( a synonym of degenerative disc disease) and found significantly more evidence of degeneration in humans when compared. The author suspected the significant differences were due to to the way non-human primates walked.
Now, if you are still reading, we are getting to the nitty gritty of this blog topic. And I will ask you to think about what is the main difference in the way we walk compared to non-human primates. Non-human primates use their arms to walk. And if you look carefully, they decompress and unload their spines when they walk.
You can see with an upright bipedal stance, the intervertebral discs will not experience unloading in human gait. Walking on two legs will not relieve the spine of the constant gravitational force. On the contrary, the use of the upper extremities in the non-human primate will provide a moment of unloading decompression to the spine when the arms are planted.
If this is the reason (which I believe to be the case) why Jurmain saw such a difference in spinal arthritis in these non-human primates, we can really learn a thing or two here in how to possibly prevent the onset and also how to treat this condition. Unloading, decompression, antigravity, traction, or how ever we describe the opposite force of gravity, has been long utilized as a form of treatment to spinal joints. Understanding how arthritis forms provides great clues into treatment strategies.