What's Causing That LBP? Facets vs. Discs vs. the SI Joint

Editor's Note: This article is a follow-up to "It's Time to Take the Sting Out of Lumbar Facet Pain," published in the July issue.

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Let's discuss some simple ways to differentiate the three major spinal joint sources of low back pain a chiropractor needs to address. Differential diagnosis is one of the keys to accuracy and success.

I know smarter docs than me have written whole books on this topic, and this has been a conundrum in the research on nonspecific lower back pain. Here is my take, inspired by Don Murphy's protocols in his book, Clinical Reasoning in Spine Pain, Volume I: Low Back Disorders; although I differ in a few places.

The Principles

As always, start by ruling out red flags. Second, look at the preponderance of the evidence. What do multiple indicators trend toward? The third principle: test your conclusions. Find a dysfunction and then test the response to your treatment or self-care exercise to see if you are on the right track.

What You'll See

What does a disc or flexion-intolerant back patient look like?^1-2 These patients are challenged by forward bending. They can't get up easily off the table, they can't tie their shoes with ease, and they have trouble sitting and/or getting up from sitting. They can also hurt when standing or strolling, but feel better with walking.

What They (and You) Feel

Their pain can be a central, deep, dull ache. They can also present with true sciatica, or pain felt in the SI area or buttock. They are likely to show nerve tension signs, usually unilateral. They hurt when they flex forward, although you may need repetitive flexion to elicit this. They will often get relief from extension or decompression, especially if they have buttock or leg symptoms. They tend to move poorly, often with excessive flexion motions, and usually lack the ability to hip hinge.

When they are inflamed or acute, the spinous or interspinous space over the involved disc or discs will be tender to palpation. This condition is so frequently missed. It does not have a single fixation pattern that accompanies it.

Find and Treat the Source

What does SI pain look like? In my opinion, we see relatively few patients with true SI pain. Use the SI provocation tests; they are a great evidence-based tool.^3-4 If the provocation tests are negative, the likelihood of true SI pain is negligible. Use palpation to determine if there is tenderness over the SI joint ligaments, including the sacrotuberous. In an SI patient, the pain is not usually felt in the lumbar spine, but more in the SI area or buttock, occasionally farther down the leg.

Suspect the SI in your pregnant or multiparous women, and your hypermobile patients. Suspect it from significant trauma to the pelvic region.

Don't just look at misalignment of the ilium,and assume that means the SI is the pain generator. We do see many patients with SI dysfunction who will respond to adjustments. In both discogenic pain and true SI pain, your adjustments should not focus on the involved disc or SI. Both of these are primarily instability syndromes. If you understand this, you will be way ahead of the average practitioner.

What about the myofascial component? In my opinion, don't think of the muscles and fascia as necessarily a cause or pain generator; think of fascial problems as additional factors in virtually all pain syndromes. Bones heal, muscles remember.

References

1. Heller M, Snell P. "Flexion-Intolerant Lower Back Pain (Part 1): Diagnosis." Dynamic Chiropractic,  Jan. 15, 2014.
2. I would be remiss in talking about the flexion-intolerant low back and discs without referencing Dr. Stuart McGill and the many resources available on his website (www.backfitpro.com).
3. Reinhold M. "Assessing the Sacroiliac Joint: The Best Tests for SI Joint Pain."
4. Laslett M. Evidence-based diagnosis and treatment of the painful sacroiliac joint. JMPT, 2008;16(3):142-52.