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 Back 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 Flags 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)

Question 4

Sciatica

Answer 4

The spinal nerves L4 – S3 come together to form the sciatic nerve. The sciatic nerve exits the posterior part of the pelvis through the greater sciatic foramen, in the buttock area on either side. It travels down the back of the leg. At the knee, it divides into the tibial nerve and the common peroneal nerve.

The sciatic nerve supplies sensation to the lateral lower leg and the foot. It supplies motor function to the posterior thigh, lower leg and foot.

Sciatica causes unilateral pain from the buttock radiating down the back of the thigh to below the knee or feet. It might be described as an “electric” or “shooting” pain. Other symptoms are paraesthesia (pins and needles), numbness and motor weakness. Reflexes may be affected depending on the affected nerve root.

The main causes of sciatica are lumbosacral nerve root compression by:

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

Bilateral sciatica is a red flag for cauda equina syndrome.

Question 5

Cancer that mets to bone

Answer 5

TOM TIP: It is worth remembering the main cancers that metastasise to the bones. A history of these in an exam patient presenting with back pain should make you think of possible cauda equina or spinal metastases. You can remember them with the PoRTaBLe mnemonic:

Po – Prostate
R – Renal
Ta – Thyroid
B – Breast
Le – Lung

Question 6

Painkillers for Back Pain

Answer 6

NSAIDs (e.g., ibuprofen or naproxen) first-line
Codeine as an alternative
Benzodiazepines (e.g., diazepam) for muscle spasm (short-term only – up to 5 days)

Question 7

Sciatica Management

Answer 7

The initial management of sciatica is mostly the same as acute low back pain.

The NICE clinical knowledge summaries (updated 2020) state not to use medications such as gabapentin, pregabalin, diazepam or oral corticosteroids for sciatica. They state not to use opioids for chronic sciatica.

They suggest considering a neuropathic medication if symptoms are persisting or worsening at follow up, but not gabapentin or pregabalin, leaving at the main choices of:

Amitriptyline
Duloxetine

Specialist management options for chronic sciatica include:

Epidural corticosteroid injections
Local anaesthetic injections
Radiofrequency denervation
Spinal decompression