Central pain is a useful clinical concept [1,2], and a common "clinical" pain phenotype [3], but it is not the result of an initial injury. It was initially proposed - Clifford Wolff - to be caused by 'windup' at the cord level and there is some evidence that windup does occur with certain, rare types, of neural injuries. However, there is virtually no evidence to support an initial pain generator in the most common of the 'central pain' spectrum disorders: FMS, HA, TMJ, IC, IBS, HA, LBP, etc. Moreover, the most recent meta-analysis of fMRI studies doesn't seem to suggest that there is a common brain mechanism between all of the various CS species.[4]
Initially, Fredrick Wolfe thought that there was a tissue level explanation for FMS. However, by 2008 he had abandoned that belief [5] and he remains a vocal skeptic that there is simple biological explanation. Dan Clauw - who I respect- still holds hope - after 25yrs - that a tissue level explanation will be found, but he is now beginning to be more circumspect and in his most recent paper he too is calling it a spectrum disorder.[6]
"We conclude that fibromyalgia and related disorders are heterogenous conditions with a complicated pathobiology with patients falling along a continuum with one end a purely peripherally driven painful condition and the other end of the continuum is when pain is purely centrally driven."
Meanwhile, 50yrs of pain psychology research has identified that the single most powerful predictor of pain
outcome, is catastrophizing/fear-avoidance. Catastrophizing is a coping trait that is established early in life and persists. It is not the result of an injury although it is associated with adverse childhood events. And - wait for it -there is emerging evidence that catastrophizing also predicts a negative response to spine injections.
1.
http://www.ncbi.nlm.nih.gov/pubmed/26266995
2.
http://www.jpain.org/article/S1526-5900(16)00566-6/pdf
3.
http://www.ncbi.nlm.nih.gov/pubmed/27166559
4.
http://www.ncbi.nlm.nih.gov/pubmed/26717948
5.
http://www.nytimes.com/2008/01/14/health/14pain.html?_r=0
6.
https://www.ncbi.nlm.nih.gov/pubmed/27291641