Adverse Changes in the Brain Caused by Chronic Pain – Is this Reversible If Pain is Eliminated?

Dear Pain Matters blog readers,

It is now known that chronic pain (eg nerve pain) changes the brain.  This is true regardless whether the pain mechanisms are peripherally and/or centrally mediated.

Thus, regardless whether the pain mechanisms reside in the periphery (e.g. in a limb) and/or centrally (in the spinal cord/brain), the brain undergoes significant, adverse changes as a result of severe and persistent pain.  This is called pain-induced cortical reorganization.

The good news is that IF this nerve pain can be blocked, via Nerve Block, pain medicine, surgery, and/or another effective treatment, the brain can change back to normal.

Several studies show this including an important study by Birbaumer et al (1997) involving 6 Phantom Limb Pain patients.

Not only was Birbaumer’s team able to show that:

(1) severe, unrelieved nerve pain (Phantom Limb Pain) causes pain-induced changes in the brain,

(2) but they also showed that these brain changes were reversible,

but only in those patients who ‘experienced a virtual elimination of current phantom pain attributable to anesthesia (quoting from Abstract).   

In other words, the successful, pain-relieving effects of the Nerve Block (Regional Anaesthesia via Brachial Plexus Blockade) was simultaneously reflected by (quoting from Abstract)a very rapid elimination of cortical reorganization‘ in the brain in 3/6 patients.

The most impressive results were observed in a 56 year old patient with severe Phantom Limb Pain who lost his upper limb 28 years earlier.  This man (‘Subject Pr3‘) underwent both:

(1) reversal of pain-induced cortical reorganization; and

(2) complete elimination of Phantom Limb Pain

within only 20 minutes after complete anaesthesia in his stump and shoulder!

NB  It is likely that the pain mechanisms were peripherally mediated in the 3 patients who had pain relief from the Nerve Block.

In summary, the Nerve Block was effective for 3/6 patients with Phantom Limb Pain.  Thus, pain-induced brain changes were rapidly reversed as a direct consequence of the pain-relieving effects of the Nerve Block in these 3/6 patients.  However, this did not happen in the latter 3/6 who did not obtain relief from the Nerve Block.

Thus, the brain appears to change ‘for the worse’ to reflect persistent pain.  On the other hand, the brain is also able to change back to normal if/when persistent pain is finally successfully blocked.

ANOTHER PATIENT WITH PHANTOM LIMB PAIN (‘TREVOR’)

Here is another patient with Phantom Limb Pain named ‘Trevor’:

While Trevor suffered from severe Phantom Limb Pain prior to his Nerve Block, his residual pain is now managed, post-Nerve Block.  Quoting (go to 27:43 in the video link):

“….At that moment, it was instant pain relief for me.”

While this video does not show images of Trevor’s brain, I would bet 2 cents that Trevor’s brain also changed, both ‘before’ and ‘after’ his Nerve Block.

 

Here’s to less chronic pain in the world,

Sabina Walker

REFERENCES

(1) Birbaumer et al; Effects of regional anesthesia on phantom limb pain are mirrored in changes in cortical reorganization; J. Neurosci (1997); 17(14), 5503-5508.

http://www.jneurosci.org/content/17/14/5503.full.pdf

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