Cauda Equina Syndrome

Question 1

What is cauda equina syndrome?

Answer 1

Neurosurgical emergency which occurs when the bundle of nerves below the end of the spinal cord are compressed

Question 2

What is the cauda equina?

Answer 2

The bundle of lumbar, sacral and coccygeal nerve roots (L1-S5)

Question 3

What do the nerve roots in the cauda equina go on to supply?

Answer 3

Pelvic organs and lower limbs

Question 4

At what vertebral level does the spinal cord terminate and what is this called?

Answer 4

L1, conus medullaris

Question 5

What are the risk factors for developing cauda equina syndrome?

Answer 5

Lumbar disc herniation - most common cause of CES
Epidural abscess/ haematoma
Trauma
Spinal tumour
Lumbar spinal stenosis 
 - Narrowing of the spinal cord may result in CES
 - Some causes are spinal osteoarthritis
 - Rheumatoid arthritis 
 - Slipped vertebra (spondylolisthesis)

Question 6

What is the incidence of cauda equina syndrome?

Answer 6

1 in 33,000 to 100,000

Question 7

What are the primary investigation for cauda equina syndrome?

Answer 7

MRI spine
- gold standard investigation and must be requested urgently

Bladder ultrasound

• to determine whether urinary retention is present
• Do not delay MRI to do bladder scan if high clinical suspicion of CES

Question 8

What investigation should you do for cauda equina syndrome if there is are contraindications to MRI?

Answer 8

CT myelography

Question 9

What are the symptoms of cauda equina syndrome?

Answer 9

Lower back pain + sciatica (97%)
‘Saddle anaesthesia’
- numbness in perianal region, groin and inner thighs
- often described as numbness while wiping
Bladder of bowel dysfunction
- Urinary retention or incontience (92%)
- rarely faecal incontience
Leg weakness + difficulty walking
Erectile dysfunction

Question 10

What are the signs of cauda equina syndrome?

Answer 10

Bilateral lower limb weakness +/or reduced sensation
Decreased or absent lower limb reflexes
Reduced perianal sensation (S2-S4) + anal tone
Palpable bladder due to urinary retention

Question 11

What is the management for cauda equina syndrome?

Answer 11

Emergency decompressive laminetomy that should be performed within 24-48 hours of symptoms onset

Early treatment = reduced risk of permanent neurological deficit

Uses posterior midline approach + laminas are removed to visualise the spinal cord

Question 12

What is the controversial management for cauda equina syndrome in patients where CES is secondary to malignancy?

Answer 12

Corticosteroids or radiotherapy

Question 13

What are the complications that can arise from cauda equina syndrome?

Answer 13

Complications of delayed presentation or decompression:

• Sexual dysfunction
• urinary dysfunction
• permanent leg weakness
• Chronic pain

Deep vein thrombosis (DVT)

• incidence of thromoboemboli in patients with CES increased
• thromboprophylaxis required

Post operative complications

• autonomic dysfunction
• recurrent herniation
• soft tissue infection
• epidural haematoma

Question 14

What determines the prognosis of cauda equina syndrome?

Answer 14

Severity + duration of compression upon the damaged nerve(s)

Question 15

What percentage of patients who had cauda equina syndrome who were treated within 48 hour of symptoms have acceptable post operative urological function?

Answer 15

75% - often have ongoing back pain + some motor or sensory deficit

The other 20% have a poor outcome - require ongoing treatment e.g. management of sexual dysfunction, self catherterisation or colostomy

Question 16

What features distinguish conus medullaris syndrome from cauda equina sydnrome?

Answer 16

Conus medullaris syndrome = often presents with upper motor neuron signs (e.g. hyperreflexia + hypertonia)

Cauda equina syndrome = usually presents with lower motor neuron signs (e.g. hyporeflexia or hypotonia)