What is Chronic Pain: A Continuation of the Science

What is Chronic Pain?

A Continuation of the Science

As previously stated in my introduction on defining chronic pain, chronic pain is not fully elucidated in the scientific community.  This blog aims to discuss some of the available theories of the existence of chronic pain from a scientific research standpoint.  This is in no way comprehensive of all the existing research but merely a conversation that
examines a few theories of why chronic pain exists.  It is also an attempt at taking dense and complicated ideas and communicating these concepts to a broader public.  With the basics out of the way, my next blog will move away from the science of pain and discuss mourning and chronic pain—how we as chronic pain sufferers experience the loss of our former bodies and how we move forward.

I would like to discuss a few findings/ theories on chronic pain but use my own experience as a jumping off point.  My injury was severe and surgery was highly recommended to clear the stenosis from the spinal column and to free the compressed nerve from the herniation of the vertebrae.  I went forward with the surgery and from a neurosurgeon’s point of view the problem was corrected.  However, it was not until a year later did a
group of medical professionals at an intensive rehabilitation program explain
to me in the simplest terms that, although the nerve was no longer compressed
and the stenosis was removed, the brain still “senses” that there has been critical
damage done to the body and muscles attempt to compensate for this damage.  In a pain specialist’s office, patients often fill out a form: rate your pain zero to 10 and place markings on an anatomical diagram stating where you feel pain.
Pain is therefore conceptualized as subjective and it is difficult to quantity.  Researchers have now found that using a functional MRI (fMRI), scientists could detect specific areas of the brain correlated to a patient’s pain.  This finding is at the
rudimentary level and specific types of pain are not understood at this time
but this finding could have consequences for treatment.   Sean Mackey, an anesthesiologist and pain researcher at Stanford explained the significance of these findings: “what we
have never done to date is show that you can use that pattern of information to
determine whether someone is in pain or not.”  He states that the
magnitude of this study reveals that while pain is an involved process and the
experiment was completed in a laboratory with a small group of subjects, these
findings uncover that pain can, indeed, be measured objectively.

Chronic pain may depend on several factors including pathophysiological conditions such as inflammation, degenerative diseases, disorders involving neurons in either or
both the peripheral and central nervous systems, as well as psychological and
social factors.  Chronic pain in itself describes the duration of the disease but not the disease itself and this adds yet another layer of complication to the picture.  I’m discussing pain in general terms but individual cases differ depending on the factors stated above.  Research in chronic pain has turned towards an understanding that trauma and noxious stimulation produce modifications in the nervous system.  The nervous system
is flexible and adaptive but these responses are deleterious to the body and the
result is chronic pain.  In fact, the nervous system’s reaction to pain aggravates pain!  Following trauma to a nerve, the nervous system aims to repair the function of an injured neuron and by doing so the threshold for pain decreases and sensitivity increases.  The body always looks to reorder the disorder but the consequences are disturbing for the patient.  However, there is more to the picture than merely the nervous system displaying higher responsiveness in pain patients.  Research has shown that trauma
can alter gene transcription (copying of the actual DNA).  While adult nerve cells do not undergo mitosis (dividing of the chromosomes), inducible transcription factors (protein
that can stimulate or repress transcription), may modify neurons towards
changing conditions in the environment similar to learning or memory but in a
deleterious manner.

Pain is an involved experience, which comprises changes in the activity of numerous neurons in the spinal cord and brain including understanding the complex events of tens, hundreds, or thousands of individual neurons.  However, I hope this
blog illuminates that we as pain patients can take heart in the fact that over
the last four decades research has greatly expanded our understanding of pain.


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