Clinical Neurodynamics: Lumbar Foramen Mechanics and Implications for Nerve Root Health

If you read my last blog post you know that I recently attended the Clinical Neurodynamics course with Michael Shacklock.  One of the most interesting bits of discussion was his research and findings with lumbar foramen biomechanics and it's relationship to the lumbar nerve root.  I've asked permission from him to write this blog post as this is part of the course and he has graciously permitted this.

For the longest time we assumed the foramen in the lumbar spine was doing what the disc did.  This is no longer the case.  The therapy approach Mckenzie has a large component of extension to drive the disc forward.  This has been shown in MRI to be true.  But for the disc to be driven forward, the posterior annulus must essentially spread or get larger to help drive the nucleus forward.  So as this spreads, the foramen actually gets smaller.

So, going forward also does the exact opposite.  As the spine bends into flexion the discs nucleus is pushed back.  The annulus gets smaller.  The foramen increases in size.  A larger foramen is created.  With the larger foramen comes 5 positive and tested outcomes.

1.  The foramen area increases between 15-40%
2.  Pressure on the nerve decreases 30-40%
3.  Size of the nerve root increases.  (from the reduction of the pressure)
4.  Electrophysiology of the nerve improves.  Strength of the contraction is better.
5.  Pain has decreased.    

Essentially the lumbar nerve roots and lumbar discs have opposite biomechanics.  This doesn't mean the Mckenzie approach is wrong.  It just means different techniques for different times  It shows how some approaches such as PRI with their flexion based activities in my opinion give relief to some peoples back pain.

It reinforces to me some very important concepts like Functional Range Conditionings approach to having segmental control of the lumbar spine.  How can you ultimately take pressure of a nerve root if you can't flex the lumbar spine segmentally?




They are showing that the same spine in a standing MRI with disc bulges go away essentially to the point you can't tell the disc has a bulge when the individual goes into flexion.  This doesn't mean flex a disc patient that is in pain.  What it does mean is perhaps the person that has fear based apprehensions to flexion because of a prognosis of disc bulge can be reeducated.

Again, there are some really important points to take away on how to use different movements at different times.  Assess what you want to happen and use movement to help facilitate the right healing environment the body needs at the time.

Thanks again to Michael Shacklock for letting me share this.  I can't recommend Clinical Neurodynamics enough for health practitioners out there.

Clinical Neurodynamics Course Review

The last 4-5 years I've pretty much realized what I want from a seminar.  I want to learn something.  I want to be able to go back to my clinic and use the information right away.  I want it to spark some type of further learning.  I'm pretty happy when I get 2 out of 3.

I recently took Clinical Neurodynamics Upper and Lower with Michael Shacklock.  This course fulfilled 3 out of 3 in my wants.  I had read the book years ago and found it to be quite interesting and had tried to incorporate some of the info into my evaluation process when I deemed it necessary.  This is a very well taught course.  He has a great teaching style and I became much better at evaluating normal vs abnormal neural tension.  There is no substitute with having the author himself give you hands on on how to do a test.  There are very subtle nuances to really do the neural tests optimally.  This is something that is hard to get from a book.  The learning of how to regress/progress each neural test for treatment is invaluable in my opinion.    

I've found that great courses are able to be incorporated with whatever technique or approach you use in practice.  In fact, as I was sitting their listening I was able to see how several techniques I have an interest in are actually saying or doing some similar thought process without knowing it.  So in a way, it helped my philosophy on my approach to practice.  

It's interesting how martial arts and stuff like Scott Sonnens IntuFLow or Pavels Mobility looks very similar to some neurodynamic upper body techniques.  

This was the first I've heard of how disc and nerve root have opposite mechanics.  This was fascinating to me.  Extension of the spine opens up disc, but closes on the nerve root and vice versa.  Perhaps this is why some Flexion based PRI exercises have helped many back pain patients.  I will be devoting a separate blog post on the lumbar foramen biomechanics, so stay tuned!

Realizing that lumbar nerve roots can have 7mm of movement when both legs are involved in a straight leg raise makes you see how an L5 ELDOA technique can be so useful.  

It had me realizing my lack of blood flow physiology knowledge.  Understanding all that takes place with venous and nerve interplay and how that affects swelling and performance.  There is a dose response to blood flow on a healthy nerve.  The research is there.  Getting edema off a nerve and increased oxygen will result in less fibroblast activity.  Better tissue quality.  

I was surprised I was the only Chiropractor there.  It seems this is just up a chiropractors wheel house.  This guy lives and works in Australia so you don't get a ton of shots learning from him in the states.  That is a shame.  

I would highly recommend this seminar to anyone that was thinking about it.