2010 Spine Control Symposium Recap: Part 1

On Saturday, August 28, 2010, I had the privilege of attending the spine control symposium put forth by the University of Queensland's Centre of Clinical Research Excellence in Spinal Pain, Injury & Health. This was a must symposium for all professionals in the rehabilitation injury who manage low back pain and with the constant growth and debate pertaining to the research in this field, I am truly thankful for such an opportunity to expand my knowledge. As such, I also believe that it is my responsibility to relay that information onto my colleagues and will make an attempt to do so below.

Please be aware that the following information is based on my interpretation of each lecture and therefore, may be subject to "lost in translation".

"Spinal Stability: The six blind men and the elephant" ~ Peter Reeves
A Reductionist vs Systems approach to management

• Interaction of the various systems is extremely important
• It is normally difficult to target the actual cause of LBP, especially in the presence of multiple findings
  • Systems approach allows you to look into the interactions between the various findings
• He uses the popular parable, "Six blind men and the elephant" to demonstrate that focusing on just one sign or symptom of low back pain is analogous to taking a reductionist approach.
• When trying to determine if something is stable, all one has to do is apply a small perturbation and observe the response
  • Systems that are in a low energy configuration are going to be stable
  • For further explanation, please see my previous post titled "Variability for Stability"
• Feedback control is probably the most important aspect of dynamic stability and this corresponds to both positive and negative feedback.
  • For stability, we always have negative feedback control
  • But there’s more than one pathway for feedback control (voluntary and reflex)
    • Note: Unfortunately, the presence of pain and dysfunction will result in delays within the reflex pathways
• Reeves demonstrated a stick balancing example to explain feedback control for stability. He introduced this concept in a recent letter to the editor in the European Spine Journal. Essentially there are two main necessities for feedback mechanisms for stability:
  • The need for tracking – we need to know the position of the mass that we are concerned with.
  • The need to know the velocity of the mass' movement
  • Lacking this results in an impairment in feedback control, and subsequently greater effort and / or displacement.
  • Note: impairments in feedback control are generally less significant during slow movement
• The future of his research and the heart of systems science lies in the modeling and its manipulation in the search for answers. His goal is to see how the system, aka the plant and the controller (see my "Variability for Stability" post), responds to different types of perturbations (not just one type of perturbation)
• The definition of "stability" is content dependent
  • Therefore he uses the concept of "risk of injury" instead.
  • He’s less concerned with the definition of stability and more concerned with how stability is achieved

"Motor Control Changes and Back Pain: Chicken, Egg, neither or both?" ~ Lorimer Moseley
Central themes (in red)

“pain and spinal control abnormalities result from implicitly evaluated needs of the organism.”

• His focus was not on the relationship between spine control and back pain but on why people with back pain actually have pain.
• (Stu McGill taking notes as always)
• Aside from humans, even the most basic biological organisms (i.e. unicellular organisms) will repel away from threat...its all about protection!

Pain vs Nociception

• Pain - unpleasant conscious sensory and emotional experiences
• The purpose of pain is protection

• The purpose of nociception is to facilitate those protective devices that humans possess

Quote:

It is “seductive” to conclude that recorded activity in c fibers and a-delta fibers will result in pain.

• Role of the thalamus is to relay and prioritize information – “what is important for the brain to know RIGHT NOW?”
• The brain is modulating nociception all the time (we have about 600 neurons descending from periaqueductal gray to modulate one ascending nociceptive neuron).
• The relationship between nociception and pain is a variable one.

• Vision is purely a sensory experience and the brain modifies it.

Pain and the Brain

• Pain is an output of the brain into consciousness
• “What is the most appropriate conscious output here?”

"trunk muscle activity results from the implicitly perceived demands on the trunk."

• Inducing experimental pain changes motor imagery performance

“we really don’t know whether motor control changes BECAUSE of pain” 
– it's a chicken and egg argument.

Considerations pertaining to the concept of nociception and protective motor control changes:

• Is it NECESSARY?
• Is it SUFFICIENT?
• *his answer was it is sufficient but it may not be necessary

Considerations pertaining to the concept of pain and protective motor control changes:

• Is it NECESSARY?
• Is it SUFFICIENT?
• *he quoted a previous paper by Hodges that stated "recurrent back pain patients in whom motor control changes are observed are often pain-free at the time of testing.

Motor control as an output of the brain to the muscles:

• The brain often asks "what are the demands on my trunk?" based on the current state, position, mobility, and vulnerability of the spine.
• Therefore, the brain can impart non-volitional motor control changes!!!

Pain as an output of the brain to the muscles:

• The brain often asks "how dangerous is this (nociceptive information) really?"
• Therefore, the brain will determine the need and presence of pain

So consequently, the brain asking itself "How Dangerous is this REALLY?" is in his view, what determines back pain.
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