Chronic Low Back Pain: From Central Pain Processing?

June 27, 2015

In a recent online conversation with other spine care specialists, the topic of “central pain processing” arose as a common explanation for chronic low back pain (CLBP).  Many believe such a phenomenon of pain shifting from a nociceptive structural origin to a spinal cord (central) generator is a common occurrence and explains a great deal of CLBP. I responded with the following posting.

“I can’t resist jumping in on this discussion of CLBP.  “Chronic” merely means it has been around for awhile – the actual duration definition varies. For some of those patients, the label “central pain processing” (CPP) may apply. But who are they? Unless we can identify them, we have no hope of delivering effective care. So how do we RELIABLY identify who they are and, just as importantly, WHO THEY AREN’T? To answer those questions, we need to take a broader look at CLBP.

One posting points out that we often can’t visualize a structural pain generator causing CLBP. It is then very common to incorrectly assume that there is none and look for an alternative explanation for the persisting pain. But there was also no generator visible when the pain was acute and presumed to be nociceptive, i.e. structural. Many then incorrectly assume that chronic patients no longer have nociceptive pain, as though that type of pain generator always recovers in 6 weeks or so. But that’s just not true.

Hippocrates said: “Healing is a matter of time, but it is also a matter of opportunity.” An injury or disorder that is never given the opportunity to heal will persist. A cut on your hand that is frequently traumatized does not heal. It needs protection to allow good healing. Likewise, a sprained ankle or fractured bone that is continually stressed and re-injured does not heal. These things have an expected healing time, but they often do not heal if not given the opportunity.

Why would LBP be any different? The prime example are those who are found to have a directional preference. Their pain centralizes and abolishes and recovery is typically fairly fast and quite predictable, despite the chronicity of their pain. This can happen many months, sometimes even years, after the onset of their pain. They were perfectly capable of healing long, long ago, but the pain generator was never provided the opportunity to recover. It wasn’t until their directional mechanics were finally explored that their pain generator’s directional preference was identified and was finally addressed. Only then, for the first time, was the generator provided “the opportunity” to heal. These folks then recover quite well.

Multiple published data report that this dir. pref. subgroup makes up 50% of the CLBP population. That’s remarkable and should get the attention of every clinician who cares for LBP. It may be a higher or lower percentage in different practices depending on: 1-other characteristics of that population, like the presence or absence of secondary gain, and 2-the training, skills and experience of the examining clinician.

This large CLBP subgroup with a dir. pref. definitely does NOT have a problem with “central pain processing”. CPP pain would not centralize and abolish rapidly with the performance of a single direction of repeated end-range spinal loading movements.

So we need to be cautious in how we characterize CLBP. There are indeed subgroups. The beauty of the dir. pref. subgroup is that its members and non-members can both be fairly easily and reliably identified. Members can be treated very effectively while non-members need further evaluation and other forms of treatment.

Only non-members of the dir. pref. subgroup should be considered to possibly belong in the CPP subgroup. The CPP subgroup is likely much smaller than many envision.”

Please share your thoughts with me and whatever questions come to mind.


One Response to “Chronic Low Back Pain: From Central Pain Processing?”

  1. High quality information, as always, Dr. Donelson! You`ve been posting those questions for a long time and seems like only few are listening. Keep the hard work! Congratulations! Great inspiration for myself!

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