Can we predict chronic spinal pain?

We're familiar with spine pain as a result of trauma but why do some people develop chronic spine pain well after initial injury and can we predict who those people will be BEFORE they get symptoms?  It appears we might be able to do that.

Studies indicate that some people develop errors in sensorimotor control following neck injury.  This is the way your brain has control over the body.  All body part locations and movements are perceived by the brain via the nerves which are embedded in the mechanical structures.  So it's clear that damage to a joint may damage these sensation detecting endings and deprive the brain of the information it requires to control movement.  The term 'sensorimotor deficit' encompasses the errors we observe and is not only due to damaged nerves but the ability of the brain to rewire itself 'wrong' (maladaptive plastic changes).

The presence of these errors can predict the development of chronic pain before it happens and interestingly some individuals can experience these errors without any obvious trauma (so called idiopathic neck pain (or pain of unknown origin)).

Our brain is involved with perceiving the world around us and making sure we safely navigate our way through it moment by moment.  Body sway, poor balance, joint movement inaccuracy, head tilt, joint clicking, jerky eye movement and even difficulty concentrating are all aspects of sensorimotor deficit and are predictors of the development of chronic spinal pain.  Furthermore stress and anxiety are both known to exacerbate and even be associated with such disorders of movement.

Why some individuals experience these cognitive disturbances is thought to be genetically influenced (as is most everything:)) but a quick look at how we are wired up reveals that our emotional responses are influenced by how 'stable' we are.

These 'higher' relationships are less predictable in part because the neurology is far more complex and interwoven once we venture into the brain proper.

Spine meets Brain - a love story

So is your love story one of harmony and balance or is it like Wuthering Heights and totally dysfunctional?

People with pain don't think about anything else but the pain so talking about brains when you first meet is not a good idea.  However while the spinal joints and their components do tear, swell and hurt the research is mounting that tells a story of the complex sensorymotor relationship between the spine and the brain and what happens to each when things don't work.  Moreover research tells the story that physically based treatments work primarily because of the effect they have on the way the brain senses or feels the spine and it's movements.

The brain moves the spine and in turn receives feedback about movement, pressure, pain and a myriad other things.  Both change in response to each other.  They improve together and decline together.  People with long term spinal pain demonstrate muscle wasting on the side of injury, poor local joint control, poor postural control, poor pain control and changes in parts of the brain concerned with emotions and thinking and autonomic changes.  The autonomic system is housed in the brainstem along with the mechanisms which are sensing and controlling the spine, balance (orientation) and posture.  They are both housed there because they talk to each other ALOT.

This is why a common presentation would be 'chronic neck/shoulder pain and stiffness, headache, head tilt, postural instability (disorientation), feeling 'out of it', trouble focusing, unable to follow a moving target without swaying, and the list can go on.  Many of these findings change with application of physically based treatments and studies are suggesting that these findings precede pain.  That's saying that in chronic cases the brain gets things wrong BEFORE a person experiences pain.

What do we mean by 'wrong'?  A person should stand upright, level and be stable but typically many chronic spine patients are crooked, unlevel and unstable.  So when treating people we look at pain control and changes in body orientation as well as another indicator of improvement.

Exercises for spinal pain - What's the use?

The following is borrowed from Matthew Long at Clinical Development International (CDI) where you'll find the full article and it's references.

Quite a few large studies investigating the effectiveness of different exercises for chronic low back pain (cLBP) have come up with apparently confusing results.  As a group these exercises are directed at specific functional weaknesses in the core muscles which act as a dynamic 'girdle' to support the lower spine and pelvis.  Do these exercises work?

The answer is no. The answer is also yes and it's not always for the reasons we think.

Generally people report subjective improvement with exercise but some report reduced pain even when there is no real change in muscle recruitment and vice versa; others display improved muscle tone but don't report a reduction in pain.  Pilates and core stability clinics have gone through a phase of being the next panacea for cLBP sufferers but it's not backed up by research.  What's going on?

One problem is that cLBP isn't a diagnosis so people experiencing cLBP do not share exactly the same problems.   A one size fits all approach is a big issue with cLBP studies as they do not target specific conditions.  However there is still useful information to be gleaned. 

Chronic pain (lasting past an expected healing time) is produced by the brain.  It's a kind of memory of the injury and the brain becomes hypersensitive to normal movement.  The brain can act as a thermostat lowering the threshold or required intensity of sensations from joint movement and give the perception of pain during normal movement.  After all the function of pain is to stop you from injuring yourself but if the injury is in the past......  It's thought to be a normal protective mechanism which can get out of hand.  People with cLBP have displayed reduced cortical or grey brain matter so it appears that chronic pain actually results in brain atrophy.

'Move it or lose it' makes even more sense these days than it did before.  Overall ANY movement or exercise which the patient undertakes and enjoys or is otherwise motivated to perform has the ability to improve both joint mechanics and the way the brain 'feels' or perceives the joint structures.

It's important for patients to understand that moving is what we are primarily evolved to do and the lack of it leads to body AND brain wasting.

Conversely chronic neck pain (cNP) is a little different with improvements in neck muscle function coinciding with reduced pain both in the neck region and interestingly in distant areas like the lower leg (so like cLBP cNP also appears to have a 'thermostat' component).

DS

What is a 'muscle spasm'?

Many people who experience back pain are told they have 'muscle spasm' and while it's certainly true that this is present in many cases it unfortunately leads to the idea that muscles can spasm on their own for no reason.

So what causes a muscle to spasm or reflexively tighten?  The spine is acutely sensitive to actual or perceived harm.  The many intricate joints which comprise the column contain the extension of the brain and it's movement and stability is a finely controlled neuromechanical system.  You've probably never considered this but muscular spasm (as distinct from cramping) never appears to occur anywhere else but the midline of the body - the spine - and the control of spinal position (an aspect of postural control) is the result of exquisitely complicated and integrated neuromuscular reflexes.  Also part of this is a 'damage/instability warning' system which can trigger muscular splinting when it perceives that joint position or a joints components are threatened.

'Back pain' can be caused by many things.  One off mild joint strains are common but should not be confused with chronic conditions which suggest repetitive injury due to a deconditioning of posture control.  In these cases 'muscle spasm' or 'back pain' is not a diagnosis merely symptoms of poor neuromuscular control.

Lumbar Spinal Stenosis

Older people commonly suffer from symptoms in their lower limbs due to a narrowing of the spinal canal.  This is called stenosis and the interesting thing is symptoms are NOT purely related to the physical narrowing of the bony canal.

As such many MRI reports indicate 'no evidence of bony canal stenosis' but does this automatically mean the person is not suffering from stenosis?  Well the answer is no and fortunately there is one sign (called a lumbar nerve root sedimentation sign) that is almost 100% indicative of stenosis.  It is thought to be partly due to the backing up of the blood supply of the spinal cord.

Like many conditions spinal stenosis can be identified early and treated effectively using conservative methods which are directed at restoring motion into these compromised areas.  More advanced cases may express weakness of the lower limbs and a loss of bowel and bladder function. These cases are appropriate surgical referrals. Research suggests however that when detected early management can effectively limit damage to the nerves and may slow or prevent deterioration.

Spinal manipulation and herniated discs

It's natural to question using spinal manipulation in the presence of a disc herniation.  After all discs only herniate when the outer fibrous rings (the annulus) are torn.  However if the disc is what is called 'contained' gentle manipulation can actually be very effective in controlling pain and restoring normal movement.

How?

One of the effects of spinal manipulation is a strong reflex analgesia, that is a potential pain blocking effect at the level of the damaged disc.  Another cause of disc mediated pain is swelling and a stasis or stagnation of the local blood supply (Bastons venous complex) to the sensitive linings which surround the spinal cord and part of the nerve root.

Many of these cases are unresponsive to steroid injection and other forms of analgesia and may often respond to manipulation.  Once the pain is under control the patient can undergo rehabilitation to prevent or reduce the risk of relapse.

Carpal Tunnel Syndrome - Axonopathy

CTS is being reclassified by some researchers as an axonopathy affecting the median nerve not simply compression of the median nerve as it passes through the carpal tunnel.

Again not all cases of CTS are the same.  This clinical ambiguity has led to controversial theories such as the 'double crush' theory which supposes that the median nerve may become irritated at multiple sites (neck and/or elbow and/or wrist) which can lead to a sensitisation of the nerve.

The nature of this neck or cervical involvement is still under debate, but most likely represents a central sensitisation of the pain pathways, rather than overt nerve compression.

For clinicians and patients widening the scope of attention to both proximal (close to the body) and distal sites can give us a number of interesting treatment strategies. These often include gentle spinal and carpal manipulation, as well as median nerve mobilisation and postural advice.


Douglas Scown