Many people come to our clinic because of nerve pain. Nerve pain can take many different forms. Perhaps the most common descriptors for nerve pain include numbness, tingling, pins and needles, and achy dull pain. Acute nerve pain can often be very sharp and electric though, as seen with a sensitive nerve in the mouth or with sciatic pain.
The nervous system can be described as having two parts; the central nervous system and the peripheral nervous system. Most people come to a chiropractic and physiotherapy clinic for conditions affecting the peripheral nervous system. The peripheral nervous system includes any nerve structures outside of the brain and spinal cord. Examples of conditions affecting peripheral nerves include spinal stenosis (lateral stenosis), lumbar disc herniation, cervical disc herniation (slipped discs), carpal tunnel syndrome, piriformis syndrome and thoracic outlet syndrome. In simple terms, peripheral nerve conditions involve entrapment or irritation of a nerve after it has left the spinal cord.
Since the central nervous system involves the brain and spinal cord, an injury to those specific areas would obviously be considered more serious than injuries to the peripheral nervous system. Examples of central nervous system injuries include meningitis, spinal cord injury, severe central stenosis, and stroke. Central sensitization is a concept that has gained a lot of attention in recent years. It refers to how our central nervous system (the brain and spinal cord) adapts and changes in response to chronic pain. The plasticity of the nervous system allows central sensitization in which the brain and spinal cord process pain stimuli in new ways after being repeatedly stimulated. A thorough explanation of the neurology behind central sensitization is beyond the scope of this blog, however the general concept is important. Under certain circumstances, the central nervous system can become “sensitised”. From that point forward it may “too easily” send pain signals even when the original stimulus isn’t as strong. For example, an injury to our arm might cause the brain and other processing stations in our spinal cord to misunderstand the pain signal from the arm. What can result is a constant pain message up to the brain and a constant pain message “from” the brain so that the patient is constantly in pain, regardless of what is still happening at the site of injury (the arm). What does this mean? For some conditions, the treatment shouldn’t be just aimed at the actual site of injury but rather stimulation of the brain and spinal cord in a way that interrupts and changes the constant focus of pain. Treatment for central sensitization is quite complex. Obviously, an accurate diagnosis is key (as with any condition) both to the peripheral injury and the sensitization occurring in the central nervous system.
There are various strategies for treating central sensitization. These include but are certainly not limited to cognitive behavioural therapy, medication, and exercise. Some recent research has suggested a new paradigm for treating various injuries in those with central sensitization, suggesting that stimulating the central nervous system through spinal manipulation may have a positive effect on chronic pain. Further research is obviously needed, but it’s an exciting thought for patients and practitioners. Perhaps for some conditions, the approach to treatment should include looking past the actual site of injury and focusing on the central nervous system!
Zafereo JA & Deschenes BK. The role of spinal manipulation in modifying central sensitization. Journal of Applied Biobehavioral Research 2015; 20: 84-99.