Posted by Michael Shacklock
One of the fantastic developments in musculoskeletal medicine has been an increased awareness of central pain mechanisms.
From this have come many benefits, not the least of which is an understanding of how and why pain may not always match a specific musculoskeletal structure or pathology. Clinically, the brain can now be treated as a key element of clinical practice.
HOWEVER - even though significant benefits have come from this, concurrent is the development of obstacles to diagnosis and therefore valuable mechanical treatment is being lost to the central nervous system.
So the objective of this blog on central pain mechanisms is to explain how we arrived here and what reasoning has been used to treat our patients.
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How We Got Here
When I first graduated, we had no idea of central pain mechanisms. At that time, I was trained as a peripheralist (or tissue-based therapist) in which we applied the following statements, the essence of which I believe came from Cyriax and other colleagues, which were used in all methods of treatment at that time:
“All pain arises from a lesion.”
“All treatment must reach that lesion.”
“All treatment must exert a beneficial effect on that lesion.”
This was based on Cartesian reasoning in which pain was thought to be directly related to nociceptor activity.
"Fix the nociception and it will fix the pain."
As young therapists, we loved this because it was simple, direct and systematic. We diligently followed these statements with all our patients which, for some, is effective.
But when we became aware of central pain mechanisms we developed a new ability to identify why certain patients do not fit this approach. The following points out several characteristics that we used to achieve this:
- pain referral outside the normal area for a particular structure
- innocuous events (physical and psychosocial) evoking pain
- the same clinical pain could be reproduced with physical tests
- some patients’ pain behaviour did not match the mechanics of the relevant structure
- variable pain responses to the same physical testing.
For a time we scratched our heads and just made things fit as best we could, or we simply forgot about it.
Then came central pain mechanisms in which dorsal horn plasticity was an early focus. We continued into the brain and suddenly things started to fit. Taking more notice of the patients' individualities, novel strategies emerged for diagnosis of a new clinical phenomenon called ‘central sensitisation’. We accepted that the problem had spread from the tissues (nociceptive) to the central nervous system. And now we are starting to accept that the problem can start in the CNS.
Since the brain can produce such big changes in pain, and different treatment approaches can produce good responses in the same clinical problem, the response is NOT always specific to the treatment.
A good example is an arc of pain with shoulder abduction. Manual treatment of the cervical spine can improve this, but so can glenohumeral mobilisations, rotator cuff or motor control exercises, visual imagery, cognitive strategies, manipulation of the thoracic spine and neurodynamic techniques. Even pressing on the tummy button can help.
The brain was taken into account and a new statement created:
“A positive response to treatment does not validate the diagnosis.”
In putting the tissue-based therapies in their rightful place, the CNS was now on the top with nociception underneath. And, with our new-found faith in that big thing in the cranium, we created wonderful generalizations:
“No brain, no pain.”
“All pain comes from the brain.”
"PAIN HAS NOTHING TO DO WITH NOCICEPTION"
Thus spoke the brain and many of us became centralists.
One of the fantastic developments in musculoskeletal medicine has been an increased awareness of central pain mechanisms.
From this have come many benefits, not the least of which is an understanding of how and why pain may not always match a specific musculoskeletal structure or pathology. Clinically, the brain can now be treated as a key element of clinical practice.
HOWEVER - even though significant benefits have come from this, concurrent is the development of obstacles to diagnosis and therefore valuable mechanical treatment is being lost to the central nervous system.
So the objective of this blog on central pain mechanisms is to explain how we arrived here and what reasoning has been used to treat our patients.
--
How We Got Here
When I first graduated, we had no idea of central pain mechanisms. At that time, I was trained as a peripheralist (or tissue-based therapist) in which we applied the following statements, the essence of which I believe came from Cyriax and other colleagues, which were used in all methods of treatment at that time:
“All pain arises from a lesion.”
“All treatment must reach that lesion.”
“All treatment must exert a beneficial effect on that lesion.”
This was based on Cartesian reasoning in which pain was thought to be directly related to nociceptor activity.
"Fix the nociception and it will fix the pain."
As young therapists, we loved this because it was simple, direct and systematic. We diligently followed these statements with all our patients which, for some, is effective.
But when we became aware of central pain mechanisms we developed a new ability to identify why certain patients do not fit this approach. The following points out several characteristics that we used to achieve this:
- pain referral outside the normal area for a particular structure
- innocuous events (physical and psychosocial) evoking pain
- the same clinical pain could be reproduced with physical tests
- some patients’ pain behaviour did not match the mechanics of the relevant structure
- variable pain responses to the same physical testing.
For a time we scratched our heads and just made things fit as best we could, or we simply forgot about it.
Then came central pain mechanisms in which dorsal horn plasticity was an early focus. We continued into the brain and suddenly things started to fit. Taking more notice of the patients' individualities, novel strategies emerged for diagnosis of a new clinical phenomenon called ‘central sensitisation’. We accepted that the problem had spread from the tissues (nociceptive) to the central nervous system. And now we are starting to accept that the problem can start in the CNS.
Since the brain can produce such big changes in pain, and different treatment approaches can produce good responses in the same clinical problem, the response is NOT always specific to the treatment.
A good example is an arc of pain with shoulder abduction. Manual treatment of the cervical spine can improve this, but so can glenohumeral mobilisations, rotator cuff or motor control exercises, visual imagery, cognitive strategies, manipulation of the thoracic spine and neurodynamic techniques. Even pressing on the tummy button can help.
The brain was taken into account and a new statement created:
“A positive response to treatment does not validate the diagnosis.”
In putting the tissue-based therapies in their rightful place, the CNS was now on the top with nociception underneath. And, with our new-found faith in that big thing in the cranium, we created wonderful generalizations:
“No brain, no pain.”
“All pain comes from the brain.”
"PAIN HAS NOTHING TO DO WITH NOCICEPTION"
Thus spoke the brain and many of us became centralists.
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