Disc Prolapse

Question 1

What is disc prolapse?

Answer 1

Where soft tissue/nucleus pulposes or the disc between vertebrae bulges or migrates.

Question 2

Aetiology of disc prolapse? (Causes) (5)

Answer 2

1. Gradual aging- related wear and tear (disc degeneration)
2. Dehydrated discs- smoking
3. Repetitive loading
4. Flexion and twisting
5. Obesity

Question 3

Epidemiology of disc prolapse? (Prevalence)

Answer 3

5-20/100,000
30-50 year olds
2:1 more males than females

Question 4

What are the types of disc prolapse?

Answer 4

Protrusion
Extrusion
Disc requestriation

Question 5

What is a protrusion?

Answer 5

Repetitive loading of the disc pressure on the annulus fibrosus, overtime can cause radial fissues, weakens the integrity of the annulus fibrosus, nucleus pulposus migrates posterior laterally, following the radial fissure leading to bulge.

Question 6

What is an extrusion?

Answer 6

Defect of the annulus fibrosus -> herniation of the nucleus pulposus beyond the confines of the disc.

Question 7

What is disc requestriation?

Answer 7

Extrusion where the disc material migrates and becomes separated from the rest of the herniation

Question 8

Clinical features of disc prolapse?(7)

Answer 8

1. Protective deformity- contralateral shift (away)
2. Spasm- protective to limit movement
3. Loss of movement e.g flexion/extension
4. Pain- chemical- inflammation, mechanical- prolapse - radicular
5. Dermatome, myotome or reflex loss/changes
6. Numbness/ tingling
7. Muscle weakness
8. Radicular pain

Question 9

What is the annulus fibrosus?

Answer 9

1. Concentric layers or lamellae of collagen fibres
2. Encapsulating the nucleus pulposus and a proteoglycan gel which binds to the collagen fibres to prevent buckling.
3. Fibres parallel/ obliquely between the two vertebrae - permit angular movement (flexion, extension, lateral flexion)
4. Provide stability against shear/torsion

Question 10

Which part of the annulus fibrosus is weaker and why?

Answer 10

Posterior - fibres more parallel, lamellae thinner, more more tightly packed, less binding gel, predisposed to degenerative change and trauma.

Question 11

What is the nucleus pulposus?

Answer 11

1. Semi-fluid gel comprising 40-60% fluid.
2. Can deform under pressure without reduction in volume.
3. Enables movememt
4. Transmits some compressive load from one vertebrae to the next.

Question 12

What are proteoglycans in the nucleus pulposus?

Answer 12

Attract/ retain water 65% in nucleus

Question 13

What are end plates and what are its functions?

Answer 13

Separate the disc from the adjacent vertebral bodies. Made of fibrocartilage.
Functions: permable for transfer of nutrients, mechanical role of preventing nucleus from bulging into vertebral body.

Question 14

What is radicular pain?

Answer 14

Occurs when the spinal nerve is irritated, radiates from the spine into limbs. May result in numbness, tingling, muscle weakness change in dermatome, myotomes and reflexes.