THORACIC SPINE REHABILITATION


WHY DOES MID BACK PAIN OCCUR?

 

In understanding why middle back pain occurs it helps to think of three different scenarios – an acute injury, back pain that has gradually gotten worse over time, and chronic/recurrent middle back pain. In all cases underlying factors relating to your anatomy, specific muscle weakness/tension, general health, age related changes and biomechanics may also contribute to your middle back pain. However, a general explanation can be provided in each case:

  1. Acute injury to the middle back results when a force (e.g. something you are lifting, an impact in an accident or an incident on the sporting field) causes a strain or damage to tissues of the spine. Depending on the mechanism, one or more tissues of the spine may be injured, including muscle, ligament, nerves, discs/joints or even the vertebrae themselves. In many cases of acute middle back injury movements that involve a twisting or side bending motion are involved. Like spraining an ankle, this acute injury results in some tissue damage, inflammation and swelling, resulting in pain and limited movement.
  2. In cases where your middle back pain has built up over time it is usually related to a habitual or repetitive posture or activity. This may be related to work, sport or recreation. Repeating a movement or posture that stresses your back in an unfavorable fashion can lead to changes in the tissues of the spine, such as repetitive inflammation, adaptive tightening of muscles, thickening of connective tissues or even stress fractures. Over time the tissues may eventually be injured, and the way we move our back may become abnormal, both contributing to pain. In particular, the middle back is a common site of stiffness and loss of mobility, a side effect of modern day life involving lots of sitting.  
  3. In cases of chronic/recurrent middle back pain, there is usually an injury (acute or gradual onset) that leads to pain. However, rather than resolving in the usual time frame of a few months at most, pain persists. This persistent pain is driven by changes in our nervous system (brain, spinal cord, nerves). The analogy here is that our body is like a computer, and our nervous system is the software. When we hurt our back our hardware (body tissue) is damaged, and we feel pain. Our body heals this damage, and pain should resolve. However, in some cases the software (nervous system) changes too and we re-program our body to move differently, avoid certain activities and we develop beliefs, fears or anxiety about pain. This can cause changes in how our muscles work, make our pain responses more sensitive, or even produce ongoing pain after our injury has healed! So even after the hardware (body tissue) has been repaired, we are stuck with this glitch in our software (nervous system) that causes problems to remain. This can manifest as chronic or recurrent middle back pain. 
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The longer you are living with back pain, the involvement of the tissues reduces, and the involvement of your nervous system increases.

 

Image credit MPC 2016 (1); adapted from Butler and Moseley 2003 (2).

 

A quick note on posture, ageing and the impact of modern life on thoracic spine health…

Whilst discussing the origins of middle back pain, the idea of ‘posture’ and alignment should be addressed. Many people are told that they have middle back pain because they have poor posture or alignment, requiring ‘adjustment’ to fix this. This idea of a spine that can be adjusted back to fully restore its function is a strange concept when you think back to the complexity and integrity of the thoracic spine, with the added support of the ribs in this area. Aside from cases of specific trauma (rib dislocation in a high force accident) developmental abnormality (e.g. scoliosis, Scheurmann’s Kyphosis) or structural deformity/fracture (e.g. osteoporosis), the thoracic spine should not be out of alignment as a primary problem. Our backs may be sore and display altered movement, muscle tension or changed postures as a response to pain, but they are almost never mis-aligned as a primary problem in all but unique circumstances.

More correctly, it is habitual poor postures (e.g. sitting slouched for hours) and repetitive activities (e.g. lifting, asymmetrical movements/postures on one side of the body such as using a mouse or throwing a ball) that can lead to injury and/or adaptive changes to the soft tissues in the thoracic spine, with resultant stiffness/pain/dysfunction. Adaptive changes may include muscle shortening, ligament thickening and asymmetry of movement. Similarly, a lack of physical activity can cause weakness in the muscles that support the spine, with subsequent dysfunction. These factors are particularly true in our modern life where we all spend large periods of our day sitting at a desk, and as a general rule we exercise less. Our thoracic spine adapts to prolonged sitting/bending, causing it to lose mobility, and we do little to maintain the movement and strength of our spine over time. This is perhaps the most common driver of thoracic pain and dysfunction seen by physiotherapists. A large proportion of the general population have what would be considered a tight, stiff, weak or sore thoracic spine!

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The increased amount of sitting and use of electronic devices in modern life could contribute to thoracic spine dysfunction

From a similar stand point ageing of the spine should also be discussed when talking about the origin of middle back pain. Many people are also told that their backs hurt because they are old, and their spine is degenerating, and that this is expected. It is true that our backs change as we age – ligaments tend to become thicker, our muscles become less extensible and our intervertebral discs lose height and become less supple. The joints in our spine may also display arthritic changes (3). However, some of these anatomical changes are quite normal – like grey hairs and wrinkles (4). Whilst they can certainly contribute to back pain or injury developing, they should not be considered the sole cause. As the old saying goes, ‘people don’t age, they rot’ – back pain with ageing is also related to changes in physical activity, habitual lack of movement and exercise and the resultant loss of strength, mobility and tissue vitality in the spine. But with modern life are people rotting faster than they should? Perhaps we need to invest more time in maintaining the health of our thoracic spine to prevent some of these negative changes.  

 

1. Kargela, M. (2016). Science Based Theatrics in Physical Therapy. Retrieved from https://modernpaincare.com/science-based-theatrics-in-physical-therapy/

2. Butler, D.S, Moseley, G.L, Sunyata. (2003) Explain Pain. Adelaide. Noigroup Publications.

3. Adams, M., Bogduk N., Burton K., Dolan P. (2013). The Biomechanics of Back Pain 3rd Ed. Churchill Livingstone.

4. Brinjikji, P.H., Luetmer, B., Comstock, B.W., Bresnahan, L.E., Chen, R.A., Deyo, S., Halabi, J.A., Turner, A.L., Avins, K., James, J.T., Wald, D.F., Kallmes & Jarvik, J.G. (2015). Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations. American Journal of Neuroradiology, 36 (4), 811-816. DOI: https://doi.org/10.3174/ajnr.A4173