Discs Flashcards
Function and Composition: Nucleus Pulposus
F: accepts compressive forces; allows deformation under pressure
C: 70-90% water, 15-20% collagen type II, 65% proteoglycans (dry weight) < GEL like substance
Term: Causes nucleus pulposus to be viscose and thick
Collagen type 2
Function and Composition: Annulus Fibrosus
F: Resist distraction, shear, and torsional stresses
C: 60-70% water, 50-60% type I collagen, 20% proteoglycan (dry weight)
Term: sheets
Lamellae
Describe the arrangement of lamellae of the annulus fibrosus
Arranged in concentric rings with the fibers alternating 60 degrees from vertical in successive layers
Annulus Fibrosus Structure: Allows for flexion motion
Thin posterior fibers
- While thin allows them to be more tightly packed thus can withstand flexion while remaining flexible
Annulus Innervation
Only the outer 1/3 is innervated (by recurrent sinuvertebral n.)
B/c the annulus is innervated it can be a source of LBP
Term: Outer annulus fibers that are attached to the vertebral bodies
Sharpey’s Fibers
Function: Vertebral end-plate
Hold disc in place
Describe the effect of nerve ending proliferation
increased pain
It has been found that those with DDD have more end plate innervation
Structure:
- Transmits load form one vertebra to the next
- Allows movement between vertebra
- Proprioception
Intervertebral Disc
2 Normal Forces that Occur to Discs
- Compression
- Distraction
2 Pathologic Forces that Occur to Discs
- Rotation
- Shear
Describe the Mechanics: Compression
The vertebral bodies move towards one another deforming the nucleus and placing pressure on the annulus (radial bulging) and end plates (bulge into trabecular bone)
The annulus and trabecular bone resist the pressure, equilibrium is reached and the load is transfer through the spine
Term: Principle WB component of L-spine
Interbody joint
Term: movement caused by WB activities or muscle forces
Axial compression
Indicates: Pain with traction of the spine
Annulus tear or facet issue
Describe the Annulus’ response to rotation
Half of the fibers are on stretch and half are lax due to alternating directions of lamella
Motion: Causing lateral shearing and lateral rotation
Lift and twist
^ You should lift and pivot instead
Term: Anterior/Posterior bending
Rocking
Describe why those with posterior disc bulges flex or rock anteriorly
An anterior rock increases pressure on the anterior nucleus and decreases pressure on the posterior nucleus effectively relieving some of the pressure off the disc bulge
2 Ways the Disc recieves Nutrition
- Passively - imbibition/diffusion
- Actively - spinal motion
Term: avascular structure
Vertebral Disc
Describe the pattern of diffusion of nutrients (for the discs)
Bone marrow > vertebral body > end plate > nucleus
describe the blood supply/flow surrounding the discs
Blood supply to outer 1/3 of annulus from spinal arteries
Blood flow through endplate from bone marrow
Optimal Stimulus for Regeneration: Annulus
Modified tension in line of stress
Unload position out of pain range
Optimal Stimulus for Regeneration: Nucleus Pulposus
Intermittent compression and decompression
Describe Normal Disc Degeneration
Disc integrity decreases with age
The ability to retain water and distribute load across the disc decreases
All 3 structures under go change
PAIN is NOT a part of normal disc degeneration
4 Biochemical Disc Changes with Age
- Decreased proteoglycan (can’t hold water - dry out)
- Increased or change in collagen type (annulus > Type 2 = can’t accept tensile forces)
- Dead cell build up > lysozome activity > weakened collagen
- Amyloid build up in discs
Changes in Disc Nutrition with Age
- Lack of movement > decreased diffusion
- Decreased fluid transport
- Injury or trauma
Force: Most disruptive to a disc
Shear
Condition:
- M > F
- 40-50
- Occupation involves lifitng, sitting, oversure
Degenerative Disc Disease
Condition:
- Constant or Intermittent pain
- Low grade ache
- Leg sx rare
- Morning stiffness/pain
- Localized in low back, rare for pain to radiate
Degenerative Disc Disease
Describe why those with DDD have morning stiffness
Over night discs rehydrate, making them highly hydrated in the morning. This increases their size, decreasing the space in the joint and contributing to morning stiffness
Condition:
Aggravating factors include
- Extending
- Bending
- Sitting
- Sit to stand
- sustained posutre
- sudden motion
- end ROM
Degenerative Disc Disease
Condition:
History includes repeated micro trauma to annular fibers, trauma to disc, or bone spur formation
Degenerative Disc Disease
Condition:
Objective
- ROM limited in the acute phase
- Pain with flex/ext, OP, sustained posture
Degenerative Disc Disease
Condition:
Objective
- SLR (-)
- Thickened soft tissue
- PAIVM increased, decreased mobility, min pain
Degenerative Disc Disease
4-6 Goals for Degenerative Disc Disease
- Decrease compression
- Promote nutrition
- Improve mobility/flexibility
- Strengthen core
- Minimize faulty movement
- Promote function
4 Components of Disc Rehydration
- Unloaded 90/90 positin or alternative reclined position
- Minimum mm activity
- Maintain unloaded position for 15-20 minutes
- Morning exercise prefered to DDD
Term: displacement of nuclear material beyond normal confines
Disc Herniation
4 Types of Disc Herniation
- Intra-spongy herniation
- Protrusion (contained herniation)
- Prolapse/Extrusion
- Sequestration
Term: break in the end plate due to heavy lifting or compression that may or may not result in an inflammatory response
Intra-spongy herniation
Defn: Schmorl’s Node
A hole in the vertebral body due to trabecular bone erosion
Erosion can occur following an intraspongy herniation due to nuclear material settling into trabecular bone
Condition:
- Occurs more commonly in the T-Spine
- 20s-30s
- Pt. unloads spine before getting up
Intra-Spongy Herniation
Term: Nucleus material migrates outward through a tear but does not escape from the outer annulus fibrosus or the PLL
Protrusion
Condition:
- 20s-50s
- Poorly localized dull ache in back
- May have buttock pain
- Increased pain in AM
- Unloads spine from sit to stand
Protrusion
Condition:
History includes sudden onset of localized back pain that may resolve with continued activity
Protrusion
Describe why herniation is not longer possible after the age of 55
The nucleus losses its viscosity so doesn’t have a consistency that would make it easy for it to escape its confines
Condition:
Objective
- Lateral shift
- Radicular pain +/–
- flexion limited or painful
Protrusion
Term: trunk deviation away from the pain
Lateral Shift
Term: Nucleus material escapes the annulus fibrosus and the PLL but remains attached to the disc
Extrusion or Prolapse
Term: A free fragment of the nucleus pulposus and may migrate to the spinal canal
Sequestration
2 Disc Herniations that are likely to Impinge Nerve Tissue
- Extrusion/Prolapse
- Sequestration
Term: Bulge lateral to the nerve root
Posterolateral Disc Herniation
Term: Shift to opposite side to open up and allow pressure release
Protective Scoliosis for Posterolateral Disc Herniation
Term: Most common disc herniation
Posterolateral Disc Herniation
Term: Bulge medial to the nerve root
Posteromedial Disc Herniation
Term: Shift to the same side to open up and allow pressure release
Protective Scoliosis for Posteromeidal Disc Herniation
Condition:
- 20-55 yo
- LBP, back and leg pain
- Associated muscle spasms +/-
Posterolateral Disc Herniation
Condition:
Aggravating factors include: flexion, sitting, sit to stand, walking, sneezing, coughing
Posterolateral Disc Herniation
Condition: Those with Posterolateral Disc Herniation are at high risk
Cauda Equina
Condition
- Severe back pain
- SLR +
Possible Cauda Equina
Condition:
History includes: sudden onset but usually due to repetitive bending, lifting or frequent lifting, recurrent episodes
Posterolateral Disc Herniation
Condition:
- Slight flexed posture
- Lateral Shift +/-
- Limited ROM/Gaurded movement
- Centralization of pain
Posterolateral Disc Herniation
4-6 Goals for (Posterolateral) Disc Herniation
- Decrease Inflammation/mm gaurding
- Protect Disc
- Centralize Pain
- Correct shift if present
- Decrease compressive forces and tension
- Promote pain free mobility/activity
Describe how lateral shift is named
Named in the direction of shoulder displacement
A left shift will relieve sx on the right
Describe how a lateral shift is correct
By moving the hips under the shoulders
Describe what will be damaged first with pure compression
Vertebral bodies and end plate before disc damage
Term: most frequent site of disc degeneration
Lumbosacral joint - L4/L5; L5/S1
