For all the scientific thought/research that has been conducted on spinal manipulation, there is still much more to be learned about how exactly it helps to decrease pain and increase function. To date, all we can really be sure of is that there are both biomechanical and neurophysiological effects in the human body.
Biomechanical effects of spinal manipulation deal with changing the relationship between different tissues within the body. Specifically, there are 4 main theories of biomechanical change due to spinal manipulation/adjustments:
1. Release of entrapped joint capsule material. The joint capsule is essentially a ligamentous structure that surrounds most joints in the body (including spinal joints). It is responsible for allowing joint motion and also protects the joint from dislocation. It is theorized that this capsule can fold inwards and become “wedged” in the joint space causing pain and limited range of motion.
2. Restoration of “buckled” motion segments. Ideally, each individual vertebrae should contribute slightly to whole body movements (think bending over and touching your toes). However, sometimes spinal segments become restricted and can’t contribute their fair share of individual motion to the entire global motion. The result is a “buckling” above and/or below the restricted segments, which places abnormal stress on the vertebral segments that are unrestricted.
3. Relieving articular/periarticular adhesions. Think of these “adhesions” as scar tissue build up between muscles, bones, and joints that are the result of injury. These adhesions may become painful and severely limit range of motion.
4. Normalization of tight muscles by reflexogenic effect. This theory can be likened to your medical doctor tapping just below your knee cap and you uncontrollably kicking your leg out. This is testing one of your many neurological reflexes. It is thought a different type of reflex may be at work during an adjustment/manipulation. This reflex may cause relaxation of overactive muscles.
Neurophysiological effects of spinal manipulation are much more complicated and much less understood. Overall, the body of research points to manipulation having specific effects on numerous neurologic markers. It’s the relationship between these markers and pain relief that remains muddied. Some logical theories have been proposed, but the exact mechanism has yet to be fully uncovered. It is beyond debate, however, that spinal manipulation does in fact produce consistent changes within the nervous system.
All in all, manipulation is just another tool in the toolbox. It’s therapeutic effects are even more profound when combined with movement/exercise. At SCWC we have seen the benefits that this combination of manipulation and exercise has, and it forms the cornerstone of our treatment plans.