Prolapsed Disc

Question 1

The most common vertebral levels affected are [] followed by []

Answer 1

The most common vertebral levels affected are L5/S1 followed by L4/L5

Question 2

Describe the pathophysiology of a prolapsed disc [3]

Answer 2

Nucleus pulposus losses the mechanical abilities to withstand the pressure and weight of the body.

Annular fibrosis surrounding the nucleus pulposus weakens

A weakening of the posterior longitudinal ligament.

All of the above contributes to the herniation of the nucleus pulposus into the spinal canal.

Question 3

Describe the clinical features of a prolapsed lower disc

Answer 3

95% of prolapsed disc cases are incidental findings and hence asymptomatic.

Remaining 5%:
* Lower back pain (most common complaint).
* Radiculopathy (dependent on the dermatome).
* Neurological weakness.
* Paraesthesia in the affected dermatome.
* Cauda equina symptoms

NB: The severity of the disease does not correlate with the size of the herniated disc on imaging studies.

Question 4

[] test: from 30 to 70 degree (known to be the most sensitive examination for lumbar disc herniation, especially nerve root L4-S1). This will reproduce a shooting electrical sensation down the affected dermatome.

Answer 4

Straight leg test positive from 30 to 70 degree (known to be the most sensitive examination for lumbar disc herniation, especially nerve root L4-S1). This will reproduce a shooting electrical sensation down the affected dermatome.

Question 5

What the is main motion [1] and reflex [1] impacted by an L3 prolapse

What the is main motion [1] and reflex [1] impacted by an L4 prolapse

Answer 5

L3
- Hip adduction
- No reflex affected

L4:
- Knee extension
- Knee jerk affected

Question 6

What the is main motion [1] and reflex [1] impacted by an L5 prolapse

What the is main motion [1] and reflex [1] impacted by an S1 prolapse

Answer 6

L5:
- Ankle dorsiflexion
- No reflex affected

S1:
Feet plantar flexion
* Achilles relfex affected

Question 7

Investigation of choice for prolapsed disc? [1]

Answer 7

Magnetic resonance imaging (MRI) scans considered to be the gold-standard due to its high sensitivity in assessing soft tissue pathologies.

Question 8

Most prolapsed discs are treated conservatively.

In which scenarios would indicate surgery? [3]
What type of surgery is most commonly used? [1]

Answer 8

Cauda equina (emergency referral to a neurosurgeon)
Progressive neurological weakness
Pain lasting > 6 weeks which does not respond to conservative management

Surgery most commonly used:
- laminectomy + micro-discectomy.