Spinal Stenosis
Narrowing of the spinal canal causing compression of the spinal cord or nerve roots, most commonly in the lumbar spine. Characterised by neurogenic claudication relieved by flexion/sitting.
Key Facts
Neurogenic claudication: bilateral leg pain, heaviness, numbness on walking; relieved by sitting or leaning forward (flexion — 'shopping trolley sign') Lumbar stenosis: most common; usually degenerative (facet hypertrophy, ligamentum flavum thickening, disc bulging, osteophytes) Cervical stenosis: myelopathy (spastic gait, hyperreflexia, Lhermitte sign, hand clumsiness) Distinguishes from vascular claudication: neurogenic relieved by flexion/sitting (not just stopping); vascular relieved by standing still MRI: gold standard for diagnosis — shows degree of stenosis, nerve root compression Conservative: physiotherapy, flexion-based exercises, analgesia; effective for many patients Surgical decompression: laminectomy for severe/progressive neurogenic claudication or myelopathy (SPORT trial) Age: predominantly >60 years; degenerative in ~90%
Overview
Key Facts
Spinal stenosis is narrowing of the spinal canal, lateral recess, or neural foramen, leading to compression of neural structures. The lumbar spine is most commonly affected.
Epidemiology
- Symptomatic lumbar stenosis: ~8–11% of >60 years
- Most common indication for spinal surgery in >65 years
- Cervical stenosis less common but potentially more serious (myelopathy)
Aetiology
- Degenerative (~90%): facet joint hypertrophy, ligamentum flavum thickening, disc bulging, osteophytes
- Congenital: short pedicles, congenitally narrow canal (predisposes to earlier symptoms)
- Other: spondylolisthesis, Paget disease, post-surgical, trauma
Pathophysiology
- Narrowing of central canal/lateral recess → compression of cauda equina (lumbar) or spinal cord (cervical)
- Venous congestion hypothesis: stenosis impairs venous drainage → nerve root ischaemia during exercise
- Extension narrows canal further → symptoms worse with standing/walking
- Flexion opens canal → symptoms relieved by sitting/bending forward
Clinical Presentation
Lumbar Stenosis — Neurogenic Claudication
- Bilateral (or unilateral) leg pain, heaviness, weakness, numbness on walking
- Relieved by sitting down, leaning forward, flexion ('shopping trolley sign')
- Walking distance progressively decreases
- Symptoms in multiple dermatomes (multilevel)
- Back pain may be present
- May be able to cycle (flexed position) even when unable to walk
Cervical Stenosis — Myelopathy
- Insidious onset clumsy hands (difficulty with buttons, writing)
- Gait disturbance (broad-based, spastic)
- Lhermitte sign (electric shock sensation down spine on neck flexion)
- Upper motor neuron signs in legs, lower motor neuron signs in arms
- Bowel/bladder dysfunction (late)
Red Flags
- Progressive neurological deficit
- Bladder/bowel dysfunction (cauda equina in lumbar; myelopathy in cervical)
- Upper motor neuron signs (cervical myelopathy — surgical urgency)
- Rapid deterioration
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Vascular claudication | Calf pain, relieved by standing still (not flexion), absent pulses, ABPI reduced | ABPI, duplex USS |
| Disc herniation | Radiculopathy, single dermatome, positive SLR | MRI |
| Peripheral neuropathy | Stocking-glove, symmetrical, sensory > motor | Nerve conduction, HbA1c |
| Hip OA | Groin pain, reduced ROM, antalgic gait | X-ray hip |
| Cauda equina syndrome | Acute bilateral legs, saddle anaesthesia, urinary retention | Emergency MRI |
Diagnosis / Investigation
Imaging
- MRI lumbar/cervical spine: gold standard; shows canal narrowing, ligamentum flavum hypertrophy, disc bulging, nerve root compression, cord compression (cervical)
- CT: if MRI contraindicated; good for bony stenosis
- X-ray: spondylosis, spondylolisthesis, alignment; poor for soft tissue
Vascular Assessment
- ABPI: if vascular claudication differential (>0.9 is normal)
Special Tests
- Treadmill test: objective walking distance assessment
- EMG/NCS: if diagnostic uncertainty; can confirm multilevel radiculopathy
Management
Non-pharmacological
- Physiotherapy: flexion-based exercises, core strengthening, stationary cycling
- Activity modification: avoid prolonged standing/extension
- Walking aids: walking stick, rollator (maintains flexed posture)
- Weight loss: if overweight
Pharmacological
- NSAIDs: short course for pain relief
- Neuropathic pain: gabapentin 300–1200mg TDS, pregabalin, amitriptyline
- Epidural steroid injection: limited evidence; short-term relief for radicular symptoms
Surgical
- Decompressive laminectomy: gold standard for severe neurogenic claudication (SPORT trial: surgery superior to conservative at 4 years for quality of life and function)
- Laminotomy, foraminotomy: less extensive decompression
- With fusion: if associated spondylolisthesis or instability
Cervical myelopathy:
- Surgical decompression: anterior (ACDF) or posterior (laminoplasty/laminectomy) — recommended for progressive myelopathy
Referral Criteria
- Spinal surgery: progressive neurological deficit, refractory neurogenic claudication, cervical myelopathy
- Emergency: cauda equina syndrome
Prognosis
- Natural history: variable; many patients stable over years
- ~30% improve with conservative management
- ~30% remain stable; ~30% slowly deteriorate
- Surgical decompression: ~65–80% good outcomes for neurogenic claudication
- Cervical myelopathy: progressive without surgery; early surgery gives better outcomes
- Post-surgical: walking distance typically improves significantly
- Complications of surgery: dural tear (~5–10%), infection, recurrence of stenosis
Other Relevant Information
Neurogenic vs Vascular Claudication
| Feature | Neurogenic | Vascular |
|---|---|---|
| Pain distribution | Bilateral, diffuse | Calf, unilateral |
| Relieved by | Sitting, flexion | Standing still |
| Cycling | Usually possible | May reproduce symptoms |
| Pulses | Normal | Reduced/absent |
| ABPI | Normal | Reduced |
| Onset with walking | Variable distance | Fixed distance |