Sciatica (lumbar radiculopathy)
Exam Tips
- In OSCEs, sciatica is suggested when leg pain is worse than back pain and radiates below the knee in a dermatomal pattern.
- Straight leg raise is sensitive but not specific; combine it with dermatomal sensory loss, reflex change, and myotomal weakness.
- Always screen for red flags (urinary retention/incontinence, saddle anaesthesia, bilateral symptoms, progressive weakness, fever, cancer history).
- Do not request routine lumbar X-ray for uncomplicated radicular pain; escalate to MRI when severe/progressive deficit or persistent disabling symptoms are present.
- Differentiate from hip disease by examining hip range of motion; pain provoked by hip movement points away from isolated lumbar radiculopathy.
- See figure: L4/L5/S1 dermatome and myotome examination map for rapid bedside localization.
Definition
Sciatica (lumbar radiculopathy) is neuropathic leg pain caused by irritation or compression of one or more lumbosacral nerve roots, most often L4-S1, that contribute to the sciatic nerve. It typically presents with unilateral pain radiating from the low back or buttock below the knee into the foot/toes, often with dermatomal sensory disturbance and possible myotomal weakness or reflex change.
Pathophysiology
In most cases, age-related intervertebral disc degeneration leads to annular fissuring and posterolateral disc herniation (commonly at L5/S1), producing mechanical compression and inflammatory irritation of an adjacent nerve root. Chemical radiculitis (cytokine-mediated inflammation) helps explain severe radicular pain even when mechanical compression is modest. Less common mechanisms include foraminal/lateral recess narrowing from spondylolisthesis or spinal stenosis, and rarely infection, epidural abscess, or metastatic spinal disease. Root dysfunction then causes dermatomal pain/paraesthesia, reduced tendon reflexes, and myotomal weakness. See figure: lumbar dermatome/myotome map (L4, L5, S1) and typical disc-root relationships.
Risk Factors
- Age 45-64 years (rare under 20 years)
- Smoking
- Obesity
- Heavy manual work, especially repeated lifting with bending/twisting
- Whole-body vibration exposure (e. g. prolonged driving or machinery use)
- Disc degeneration (including genetic susceptibility)
- Poor general health/comorbidity burden
Clinical Features
Symptoms
- Unilateral leg pain radiating below the knee to the foot/toes
- Low back or buttock pain, usually less prominent than leg pain
- Dermatomal numbness or tingling
- Pain aggravated by posture/loading and sometimes by cough/sneeze/strain
- Functional limitation (walking, work, sleep)
- Red-flag symptoms to ask about: urinary retention, saddle sensory change, bilateral sciatica, systemic features, cancer history
Signs
- Positive straight leg raise: reproduction of radicular leg pain below about 60 degrees hip flexion
- Dermatomal sensory loss (e. g. L5 dorsum of foot, S1 lateral foot)
- Myotomal weakness (e. g. ankle dorsiflexion/plantarflexion weakness)
- Reduced reflexes (e. g. ankle jerk in S1 involvement)
- Gait disturbance due to pain or motor deficit
- Features suggesting alternative/serious disease: hip movement pain, upper motor neurone signs (e. g. extensor plantar response), fever/spinal tenderness
Investigations
Management
Lifestyle Modifications
- Provide reassurance and safety-netting; explain expected course and warning symptoms
- Encourage activity and early return to normal function/work where possible (avoid prolonged bed rest)
- Structured exercise/physiotherapy with progression based on disability risk and psychosocial barriers
- Address modifiable risks: smoking cessation, weight reduction, ergonomic/manual-handling advice, vibration exposure reduction
- Use shared decision-making and risk stratification (e. g. STarT Back approach) for follow-up intensity
Pharmacological Treatment
NSAIDs (first-line drug option if no contraindication)
- Ibuprofen 400 mg orally three times daily with food (max 2.4 g/day)
- Naproxen 250-500 mg orally twice daily (max 1 g/day)
Use lowest effective dose for shortest duration; assess GI, renal, and cardiovascular risk. Co-prescribe gastroprotection when risk factors present, e. g. omeprazole 20 mg once daily.
Short-course weak opioid (only if severe pain and NSAIDs unsuitable/insufficient)
- Codeine phosphate 30-60 mg every 4-6 hours as needed (max 240 mg/day)
Use brief rescue therapy only; review quickly for sedation, constipation, nausea, dependence risk, and driving safety.
Drugs generally not recommended for routine sciatica
- Gabapentin
- Pregabalin
- Benzodiazepines
- Oral corticosteroids
Evidence of limited benefit with potential harm; avoid routine use in primary care unless specialist-directed for specific indications.
Surgical / Interventional
- Urgent emergency decompression for suspected cauda equina syndrome
- Lumbar microdiscectomy/decompression for persistent disabling radicular pain with concordant imaging after failed conservative care
- Specialist spinal interventions (e. g. image-guided epidural steroid injection) may be considered in selected severe acute radicular pain pathways
Complications
- Persistent or recurrent pain (chronicity)
- Long-term disability and reduced quality of life
- Psychological distress and fear-avoidance behaviours
- Work absence, reduced productivity, and possible job loss
- Increased healthcare utilization
Prognosis
Overall prognosis is favourable: many patients improve substantially within weeks to a few months, and around half recover spontaneously by about 6 weeks. Recurrence is common, and a minority develop fluctuating or persistent symptoms at 1 year and beyond; poorer outcomes are linked to adverse psychosocial and occupational factors, longer symptom duration, and higher baseline disability.
Sources & References
✅NICE Guidelines(1)
- Sciatica (lumbar radiculopathy)[overview]