Chronic Pain: Do We Even Know What We Don't Know?

My wife is currently training to become a yoga instructor.  Our conversations have begun to revolve around concepts like "being present" and "finding my center."  I'm a somewhat reluctant participant in such conversations and even though I understand all of the individual words being used, I admit the concepts are largely lost on me.  One thing that has resonated with me, though, is the humility that one can derive by recognizing what one does not know.  We can start to develop more rational and realistic responses to life's problems when we step back and question the basis of our views.

Two studies caught my attention recently and reminded me of this important principle.  In the swirl of debate and conjecture surrounding contemporary approaches to pain management, I think it's critical for us to distinguish what we know and what we don't know.

First, from the joint efforts of radiology service provider Spreemo and the Hospital for Special Surgery (HSS), we learned that objective diagnoses for low back pain aren't as straightforward as one might think.  A single patient was sent to 10 different centers to get an MRI of the lower back.  Of the 49 distinct objective findings identified across the 10 centers, not a single finding was identified by all 10 centers.  The study points to a potential diagnostic error rate of up to 43%.  

Next, from the Proceedings of the National Academy of Sciences, we learned that opioids might actually prolong neuropathic pain.  The paper titled "Morphine paradoxically prolongs neuropathic pain in rats by amplifying spinal NLRP3 inflammasome activation" is a technical piece, to say the least and I won't claim to have comprehended all of it.  But here's a snippet from the conclusion of the paper that I did understand (mostly):

In summary, the mechanisms underlying the transition from acute to chronic pain are poorly understood. We discovered that a short course of morphine administered upon expression of neuropathic pain remarkably doubled the duration of CCI-allodynia. This process was dependent upon dorsal spinal microglial reactivity and NLRP3 inflammasomes. These findings comport with prior demonstrations that repeated immune challenges induce a transition from acute to chronic pain, which may also underpin pain comorbidities. An evaluation of the long-term consequences of opioid treatment for chronic pain will identify whether this phenomenon manifests clinically.

It's really astounding to think about how much we don't know when it comes to chronic pain.  For all the time we spend debating the use of opioids for the treatment of low back pain, it's both frightening and illuminating to realize we get the diagnosis wrong almost 50% of the time and the drugs we use to treat it might actually make it worse.  

Long way to go...

Michael
On Twitter @PRIUM1

Low Back Pain: What's the Best Medication Approach?

Wouldn't it be great if there was a study that compared patient outcomes among several groups based on a single, common diagnosis but several potential medication regimens?  How might such a study be designed?

Perhaps you could identify 300 patients, all of whom presented in the emergency department of a hospital with acute low back pain.  We might assess their level of disability utilizing a widely used health status measure like, say, the Roland Morris Disability Questionnaire (RMDQ).  We might divide the patients into three groups based on their medication regimen:
1. Naproxen + placebo
2. Naproxen + cyclobenzaprine
3. Naproxen + oxycodone/acetaminophen

We'd make sure the initial RMDQ scores were roughly similar across all three groups.  We'd also make sure all three groups were similar demographically and that each patient received education on management of low back pain prior to discharge from the hospital.    Then we'd call the patients at the 1 week mark and the 3 month mark to re-assess their level of disability.  That would tell us which of the three various medication regimens provides for the best patient outcomes.

Such a study would be helpful, right?

Well, researchers at Montefiore Medical Center and Albert Einstein College of Medicine conducted just such a study and the results are compelling.

It appears that "take two Aleve and get some rest" may, in fact, be the best (and certainly the safest) course of action when it comes to preventing acute LBP from becoming chronic LBP.

Michael
On Twitter @PRIUM1