Thursday Thoughts: Why Stenosis May Respond to Extension or Flexion

Those of you who may be applying a repeated motions exam to find a directional preference, or using a pure MDT approach will find that most cervical spines and lumbar spines respond to extension or some form of unilateral loading.

It usually does not matter what the x-ray or CT scan says. A lack of joint space, degeration etc, normally does not correlate with pain or function levels. An astute mentee noticed in his practice that sometimes it does. The question was, "Why do some stenosis patients respond to flexion?"
I gave my thoughts about Flexion Rapid Responders back in this post, here and here. Here are my current thoughts

the brain is always taking various inputs and making one of two decisions 1) danger 2) safe
things seem to happen when things add up faster than the brain can think "green light"
in the case of stenosis, my thoughts are that

narrowing
limited hip extension
limited thoracic mobility

causes excessive WB and thus load to the lumbar spine

Extension or a repeated loading strategy is no longer novel if the brain is perceiving loading/WB/extension as a threat. The novel strategy then becomes various degrees of unloading/flexion, eventually to end range. In addition, changing hip and thoracic mobility hopefully causes less WB load in standing and walking not enough to change space/degeneration, but enough of the accumulation of loading. Essentially changing the perception that loading is dangerous, to loading is safe.

This also why many lumbar or cervical cases that have central or lateral stenosis still seem to respond to extension or loading rather than flexion or unloading. Extension for many patients regardless of what their spine looks like when they're lying in a tube, is still novel, depending on their day to day activities.

Keeping it Eclectic...