Key Facts

Low back pain is defined as pain in the area between the lower rib margin and the gluteal folds. It is the leading cause of disability worldwide. Most cases are non-specific (mechanical) with no identifiable serious underlying cause.

Epidemiology

• ~60–80% of adults affected at some point
• Leading cause of disability globally (Global Burden of Disease)
• Peak prevalence: 35–55 years
• Cost to NHS and economy: >£12 billion/year

Aetiology

• Non-specific (mechanical): ~90% (muscle strain, facet joint, disc degeneration — often impossible to identify exact source)
• Disc herniation/prolapse: ~5%
• Spinal stenosis: ~3%
• Serious pathology: <1% (malignancy, infection, cauda equina, fracture)

Pathophysiology

• Non-specific: likely multifactorial — deconditioning, postural, psychosocial
• Disc herniation: nucleus pulposus herniates through annulus fibrosus → nerve root compression → radiculopathy
• Central sensitisation: in chronic LBP, pain processing becomes amplified

Non-specific (Mechanical) Low Back Pain

• Aching, stiffness localised to lumbar region
• Worse with activity, better with rest (variable)
• Morning stiffness <30 minutes
• No neurological deficit

Radiculopathy (Sciatica)

• Leg pain > back pain (dermatomal distribution)
• L4/L5 or L5/S1 most common
• Positive straight leg raise
• Neurological signs: weakness, numbness, reflex changes

Red Flags

• Cauda equina: bilateral leg pain/weakness, saddle anaesthesia, urinary retention/incontinence, reduced anal tone → EMERGENCY MRI + surgical referral
• Malignancy: age >50 or <20 with new onset, weight loss, history of cancer, constant pain (not relieved by position), night pain
• Infection: fever, IVDU, immunosuppression, recent procedure
• Fracture: significant trauma, osteoporosis, steroid use
• Inflammatory spondyloarthropathy: age <40, morning stiffness >30 min, improves with exercise, family history

Yellow Flags (Psychosocial Risk for Chronicity)

• Catastrophising, fear-avoidance beliefs
• Low mood, anxiety
• Passive coping (bed rest, reliance on treatments)
• Work dissatisfaction, compensation claims

Acute Non-specific LBP

• No investigations routinely required (NICE NG59)
• Clinical assessment sufficient

If Red Flags Present

• Urgent MRI: cauda equina, suspected malignancy, infection
• Bloods: FBC, ESR/CRP, calcium, ALP, PSA, SPEP (malignancy screen)
• X-ray lumbar spine: fracture
• MRI sacroiliacs: inflammatory spondyloarthropathy

Chronic LBP (>12 weeks)

• Imaging only if considering surgical referral or specific diagnosis suspected
• MRI: disc herniation, spinal stenosis, inflammatory disease
• Note: degenerative disc changes are extremely common in asymptomatic individuals and do NOT explain pain

Non-pharmacological (NICE NG59 — FIRST-LINE)

• Self-management: stay active, avoid bed rest, reassurance
• Group exercise programme: biomechanical, aerobic, yoga, Pilates
• Psychological therapy: CBT (especially if yellow flags)
• Manual therapy: spinal manipulation, mobilisation, massage — only as part of treatment package

Pharmacological (NICE NG59)

• NSAIDs: ibuprofen 400mg TDS or naproxen 500mg BD (lowest effective dose, shortest duration)
  • With PPI cover if >45 or risk factors
• Weak opioids (short course only): if NSAIDs insufficient
• DO NOT routinely offer: paracetamol alone, gabapentinoids, opioids long-term, antidepressants, benzodiazepines
• Neuropathic pain (radiculopathy): consider amitriptyline, duloxetine, gabapentin, pregabalin per NICE CG173

Surgical/Interventional

• Disc herniation with radiculopathy: surgical microdiscectomy if persistent >12 weeks despite conservative
• Spinal stenosis: decompressive laminectomy if significant neurogenic claudication
• Spinal fusion: very limited evidence for non-specific LBP; only after comprehensive conservative programme

Referral Criteria

• Emergency: cauda equina → same-day MRI + neurosurgery/spinal surgery
• Urgent: suspected malignancy, infection, progressive neurological deficit
• Routine: persistent radiculopathy >6 weeks with neurological deficit, spinal stenosis unresponsive to conservative

• Acute: ~90% resolve within 6 weeks
• ~5–10% develop chronic LBP (>12 weeks)
• Chronic LBP: significant disability, reduced quality of life
• Sciatica: ~75% resolve within 12 weeks with conservative management
• Surgery for disc herniation: ~85–90% good outcomes
• Yellow flags (catastrophising, depression): strongest predictors of chronicity
• Cauda equina: surgical decompression within 48 hours reduces permanent deficit
• Long-term opioid use: no evidence of benefit; significant harm

NICE NG59 Key Recommendations