Contributing Factors to LBP Flashcards
Biomechanical Contributing Factors
noxious input from abnormally loaded tissue is driving the problem
Biomechanical Contributing Factors - four main issues
- movement is slower and more cautious in individuals with LBP
- for niche activities where there is LBP, individuals spend a prolonged period time at end rage of lumbar movement (eg. cyclists spend a long time in excessive lumbar flexion)
- potenital sub-optimal load sharing between the lumbar spine and hip
- people with LB tend to use Lx early on in movement
- have greater contribution of Lx to movement
- have decreased hip range and hip asymmetry
- have poor hip muscle function
- have dysfunctional load sharing - Greater compressive loads in individual with LBP whilst performing activities (mainly lifting) when compared to individuals without LBP
Structural Pathology - when is it important?
Important for individuals with - serious medical condition - radiculopathy - degenerative central canal stenosis However - must remember that these abnormalities sometimes exist in individuals without any LBP
For OLBP - evidence shows that imaging and changes to structure are not helpful at all
Muscular Dysfunction Contribution - Punjabi Model of Spinal Function
Passive sub-system - passive support and guidance to the joint
Active sub-system - intrinsic muscle characteristics (size, length and orientation of the muscle)
Control sub-system - skill required in order to appropriately activate the muscles
Musc Dysfunction - Local Muscles
inner unit
- act on the lumbar spine and also attach to it
- short, medial and deep back muscles
- main job in stabilising
- can act segmentally on the spine
- have osseous/broad insertions
- more oxidative - high fatigue resistance
- able to move the lumbar spine independently from the thoracic spine
- control joint stiffness
- control segmental movement trajectory
- unable to balance large external loads
Musc Dysfunction - Global Muscles
outer unit
- act on the trunk but don’t have direct attachment to the lumbar spine
- long, lateral and superficial
- have tendinous insertions
- more glycolytic biology - less fatigue resistance
- unable to have segmental control - move both the lumbar and thoracic spine together
- have little effect on specific intervertebral control
- unable to compensate for loss of local function
- designed for global rigidity
- produce stabilisation under large external forces via co-contraction
Musc Dysfunction - Altered Musculature
wasting of posterior muscles
increased percentage of fat in muscles
wasting of the psoas muscles
transition from slow twitch to fast twitch fibres
Musc Dysfunction - resultant functional problems
trunk muscles are deconditioned
leg muscles are deconditioned
impaired control of the back muscles
altered lifting mechanics
Musc Dysfunction - deconditioning of the trunk muscles
weak lumbar extensors
poor endurance of lumbar extensors and flexors
- main contributing factor
- predictor of future back pain
- alligns with aggravating activities described by patients
Musc Dysfunction - deconditioning of leg muscles
Pts with LBP more likely to have
- weaker hip abductors
- reduced endurance of hip abductors
- weaker knee extensors
- weaker hip extensors
Musc Dysfunction - impaired control of back muscles
lose flexion relaxation - extensors don’t turn off fully during flexion
asymmetric muscle recruitment
erratic muscle contraction
decreased force rate development
take longer to recover equilibrium with sudden load release
take longer to recover equilibrium with sudden load
delayed off set sudden release
delayed onset of appropriate muscles with sudden load
greater co-contraction of muscles - lose precision of muscle contraction
take longer to recover equilibrium with arm movement
increased disruption to balance
Musc Dysfunction - altered lifting mechanics
earlier muscle activation takes longer to switch muscles off greater co-contraction of msucles greater asymmetry in muscle contraction same with other functional tasks - walking, standing, sit to stand etc.
Neural Processing - contribution to LBP factors
increased efficiency of nociceptive processing
less attentive to non-noxious inputs
put more importance on danger than safety
representation of the back changes
back feels different
Neural Processing - increased efficiency of nociceptive processing
- increased sensitivity over the back
- increased sensitivity elsewhere in the body
- enhanced facilitation and temporal summation of pain
Neural Processing - less attentive to non-noxious input
- poorer tactile acuity
- poorer proprioceptive activity
- less sensitive to muscle vibration - don’t initiate a response to muscle stimulus
- poorer overall balance
- display sensory neglect like features
