Why the Structural Model Has Limits
Part 6A · Section 6: How Manual Therapy Works
Why the Structural Model Has Limits
The dominant twentieth-century explanation for what manual therapy does — correcting alignment, fixing subluxations — turns out to lack empirical support. What actually changes is the nervous system.
The structural model — joints misaligned, vertebrae subluxated, the practitioner's job to put things back — dominated manual therapy for most of the twentieth century. Science has substantially complicated this picture.
What the Research Found
A 2024 systematic review examining whether spinal manipulation produces measurable anatomical structural changes concluded that the empirical evidence supporting structural change as the mechanism of clinical improvement is insufficient.
A separate study of lateral spinal stenosis found no significant association between MRI-graded anatomical severity and patient-reported pain or disability. More structural damage did not reliably mean more pain — which means less structural damage does not reliably mean less pain either. The tissue state and the pain state are not the same thing.
The Nocebo Problem with Structural Language
When patients are told their spine is "out of alignment," research shows these explanations increase fear, reduce movement confidence, and promote avoidant behaviors. The explanation itself can worsen recovery — a nocebo effect that is clinically significant and entirely avoidable.
This has a direct implication for clinical communication: how a practitioner explains what they are doing matters neurophysiologically. A threatening explanation produces a different neural response than a non-threatening one — even when the physical technique is identical.
Modern evidence points toward neurophysiological mechanisms as the primary basis for manual therapy's effects. Not alignment. Not subluxation. The nervous system.
Key Takeaways
- The traditional structural model lacks sufficient empirical support as a mechanism for clinical improvement
- Anatomical findings on MRI correlate poorly with pain severity
- Structural language can produce nocebo effects by increasing fear and reducing movement confidence
- Modern evidence points toward neurophysiological mechanisms as the primary basis for manual therapy's effects
Fagundes C, Herzog W. Mechanisms of manipulation. Chiropr Man Therap. 2024.
Norisyam Y, et al. No significant association between clinical symptoms and MRI findings. Cureus. 2023.
Gevers-Montoro C, et al. Neurophysiological mechanisms of chiropractic spinal manipulation. Eur J Pain. 2021;25(7):1429–1448.
CALee Acupuncture — Hoon Lee, L.Ac., DAOM(c)
Buena Park, CA · Korean Therapeutic Bodywork · Acupuncture · Pain Management
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