Intervertebral disc

Question 1

Etiology/incidence of conditions related to the IVD

Answer 1

• 80% adult population will expereince LBP
• Estimated 40% of those with chronic non-specific LBP have pain of a discogenic origin
• 90% of all spinal surgeries are to treat symptoms related to IVD degeneration

Question 2

Structure of IVD

Answer 2

• annulus fibers - type 1 fibers
• nucleus pulposus - type 2 + GAGs
• cartilage end plate

Question 3

Function of IVD

Answer 3

• Spread compression forces
• acts as a spacer
• under heavy loads = more stability (stiffens up)
• under light loads = provides mobility (aids)
• keeps tension in motion segmetn

Question 4

Innervation of IVD

Answer 4

• segmentally: ventral Rami
• non-segmentally: grey rami communicantes

Question 5

Aging IVD

Answer 5

• degeneration early 2nd decade
• decrease type 2 collagen (drys out and replaced with type 1)
• less able to distribute forces radially
• loads transmitted directly onto annulus

Question 6

Incidence of IVD problems at what segments in the lumbar spine

Answer 6

• L4-L5 = 57%
• L5-S1 = 41%
• root level L5 = 44%
• Root level S1 = 54%

Question 7

Motion segment degeneration process

Answer 7

• stage 1: circumfrential tears
• stage 2: radial tears, HNP, laxity
• Stage 3: stiffening, stenosis

Question 8

Phases of HNP

Answer 8

• internal disc displacement:slight tear in annulus
• HNP protrusion: annulus and nucleus stick out
• HNP extrusion: parts of nucleus are leaking out
• HNP sequestration: nucleus and some annulus become seperated from whole disc?

Question 9

IVD as a pain source

Answer 9

• innervated
• raidal tears to outer annulus
• avenue for nucleus

Question 10

IVD healing

Answer 10

• prolonged and inadequate 3-12 weeks
• fibrous plug
• 60% original strength

Question 11

Motion Segment Degeneration

Stage 1

Answer 11

• Circumfrential tears
• within the annulus rings
• in periphery it can be painful

Question 12

Motion Segment Degeneration

Stage 2

Answer 12

• the tears start to go towards the center
• through the rings
• internal disc displacement = disc bulges are likely to occur

Question 13

Motion Segment Degeneration

Stage 3

Answer 13

• stiffening
• stenosis

Question 14

Degeneration of disc

Answer 14

• starts to degnerate in 2nd decade = teens
• if annulus is disorted it can be painful