Back pain and sciatica

Question 1

Causes of mechanical back pain

Answer 1

Muscle or ligament sprain

Facet joint dysfunction

Sacroiliac joint dysfunction

Herniated disc

Spondylolisthesis (anterior displacement of a vertebra out of line with the one below)

Scoliosis (curved spine)

Degenerative changes (arthritis) affecting the discs and facet joints

Question 2

Causes of neck pain

Answer 2

Muscle or ligament strain (e.g., poor posture or repetitive activities)

Torticollis (waking up with a unilaterally stiff and painful neck due to muscle spasm)

Whiplash (typically after a road traffic accident)

Cervical spondylosis (degenerative changes to the vertebrae)

Question 3

Red flag causes of back pain

Answer 3

Spinal fracture (e.g., major trauma)

Cauda equina (e.g., saddle anaesthesia, urinary retention, incontinence or bilateral neurological signs)

Spinal stenosis (e.g., intermittent neurogenic claudication)

Ankylosing spondylitis (e.g., age under 40, gradual onset, morning stiffness or night-time pain)

Spinal infection (e.g., fever or a history of IV drug use)

Ruptured AAA

Question 4

Non-spinal causes of back pain

Answer 4

Ruptured AAA
Kidney stones
Pyelonephritis

Pancreatitis
Pneumonia
PID, Endometriosis
ETC…

Question 5

What is the sciatic nerve path?

Answer 5

Spinal nerves L4 – S3 form the sciatic nerve.

The sciatic nerve exits the posterior pelvis through the greater sciatic foramen, in the buttock area on either side and travels down the back of the leg.

At the knee, it divides into the tibial nerve and the common peroneal nerve.

Question 6

What is the function of the sciatic nerve

Answer 6

Sensation to lateral lower leg

Motor function to the posterior thigh, lower leg and foot

Question 7

Sciatica symptoms

Answer 7

Unilateral (usually) - pain from the buttock down the back of the thigh

Sharp electrical pain

Paraesthesia (pins and needles)
Numbness
Motor weakness

Reflexes may be affected depending on the affected nerve root

Question 8

Common causes of sciatica

Answer 8

Herniated disc
Spondylolisthesis (anterior displacement of a vertebra out of line with the one below)
Spinal stenosis

Question 9

What may bilateral sciatica indicate?

Answer 9

Red flag for cauda equina syndrome

Question 10

Back pain history questions to ask

Answer 10

Spinal fracture:
- Major trauma

Ankylosing spondylitis:

• Stiffness in the morning/with rest
• Gradual onset
• Night pain

Cancer:

• Weight loss
• Gradual onset
• Night pain

Cauda equina:

• Bilateral sciatica
• Saddle anaesthesia
• Urinary retention/incontinence
• Faecal incontinence
• History of cancer with possible metastasis (could be the cause)

Spinal infection:

• Fever
• IVDU

Question 11

Back pain examination findings

Answer 11

Localised tenderness to the spine (spinal fracture or cancer)

Bilateral neurological motor or sensory signs (cauda equina)
Bladder distention implying urinary retention (cauda equina)
Reduced anal tone on PR examination (cauda equina)

Question 12

What examination can be used to diagnose sciatica?

Answer 12

Sciatic stretch test

Patient supine, leg lifted to limit of hip flexion and dorsiflex ankle

If it recreates sciatic pain - indicates sciatic nerve root irritation

Symptoms improve on flexing knee

Question 13

Investigations for lower back pain

Answer 13

If mechanical - diagnosed clinically and no investigations

X-ray for spinal fractures

Question 14

Investigation and management for suspected cauda equina

Answer 14

Same-day referral to on-call orthopaedic team

Emergency MRI spine (within hours of presentation)

Question 15

Investigation for suspected Ank Spond

Answer 15

Inflammatory markers (CRP and ESR)

X-ray of the spinal and sacrum (may show a fused “bamboo spine” in later-stage disease)

MRI of the spine (may show bone marrow oedema early in the disease)

Question 16

Management of acute lower back pain

Answer 16

Exclude serious underlying causes

Analgesia - NSAIDs first line, codeine alternative
- Benzodiazepines e.g. diazepam for muscle spasm (up to 5d treatment)

They specifically state not to use opioids, antidepressants, amitriptyline, gabapentin or pregabalin for low back pain

Safety net for red-flag Sx

(Assess risk of developing chronic back pain (e.g. StarT back tool) - if medium/high can consider physio)

Question 17

Management of sciatica

Answer 17

Initial management same as acute low back pain including analgesia and exercises

Can consider neuropathic agent - amitriptyline or duloxetine (not gabapentin/pregabalin)

Chronic sciatica specialist options:
Epidural corticosteroid injections
Local anaesthetic injections
Radiofrequency denervation
Spinal decompression