Degenerative narrowing of the lumbar canal in older adults causing neurogenic claudication relieved by spinal flexion.
Also known as: LSS, spinal stenosis, lumbar stenosis, neurogenic claudication
Overview
Narrowing of the lumbar central canal, lateral recess, or neural foramina producing compression of the cauda equina or exiting nerve roots. Most commonly degenerative in older adults; congenitally narrow canals predispose to symptomatic presentation at lower thresholds.
Epidemiology
Most common cause of lumbar spine surgery in adults over 65. Prevalence rises with age; symptomatic LSS in ~10% of adults over 60.
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Question 1MusculoskeletalMedium
A 68-year-old man reports several months of aching pain and numbness in both legs that comes on after he walks a block or stands at the kitchen counter. He notices the pain eases when he sits or leans forward over a grocery cart, and he can walk farther going uphill than downhill. His medical history includes hypertension and degenerative disc disease. On exam while standing, lumbar extension is limited and reproduces his leg symptoms; pedal pulses are 2+ and symmetric, and the neurologic exam is otherwise normal. Which of the following is the most likely diagnosis?
AHip joint osteoarthritis
BPeripheral artery disease
CLumbar disc herniation
DLumbar spinal stenosis
ELumbar facet joint syndrome
Reveal answer & full explanation
Correct answer: D — Lumbar spinal stenosis
AHip joint osteoarthritis
BPeripheral artery disease
CLumbar disc herniation
DLumbar spinal stenosis✓
ELumbar facet joint syndrome
Why Lumbar spinal stenosis is correct
Neurogenic claudication in an older adult: bilateral leg pain and numbness brought on by walking or standing (lumbar extension) and relieved by sitting or leaning forward (flexion), which widens the canal — the classic shopping cart sign.
Walking farther uphill (flexed posture) than downhill (extended posture) and reproduction of symptoms with standing lumbar extension are hallmark positional features.
Preserved, symmetric pedal pulses point away from a vascular cause; MRI of the lumbar spine is the diagnostic test of choice.
Why the others are wrong
Peripheral artery disease: vascular claudication is usually calf pain relieved by simply standing still rather than by changing posture, with diminished pulses and an ABI below 0.9; this patient has normal symmetric pulses.
Lumbar disc herniation: typically a younger patient with sharp dermatomal pain and a positive straight-leg raise, not a months-long posture-dependent bilateral pattern.
Hip joint osteoarthritis: produces groin pain reproduced by hip range of motion with a positive FABER test, not walking-induced bilateral leg symptoms relieved by spinal flexion.
Lumbar facet joint syndrome — facet-mediated pain is also provoked by lumbar extension and eased by sitting in an older patient with degenerative spine disease, but it causes axial low back pain with nondermatomal referral to the buttock or thigh and no numbness, not walking-induced bilateral leg pain and numbness (neurogenic claudication).
Question 2MusculoskeletalMedium
A 68-year-old man reports 8 months of aching pain and heaviness in both calves and thighs that begins after he walks about one block. He notes the pain eases when he sits or leans forward over his grocery cart, and he can ride a stationary bike without difficulty. He has hypertension and takes lisinopril. On examination, lower-extremity pulses are 2+ and symmetric, strength is full, and reflexes are slightly diminished at the ankles; the resting back and neurologic exam are otherwise unremarkable. Which of the following is the most appropriate next diagnostic test?
AMRI of lumbar spine
BLumbar spine CT scan
CEMG of lower extremities
DAnkle-brachial index
ELumbar spine x-rays
Reveal answer & full explanation
Correct answer: A — MRI of lumbar spine
AMRI of lumbar spine✓
BLumbar spine CT scan
CEMG of lower extremities
DAnkle-brachial index
ELumbar spine x-rays
Why MRI of lumbar spine is correct
The history is classic neurogenic claudication from lumbar spinal stenosis: bilateral leg pain with walking and standing, relief with flexion (sitting, leaning over a cart, the shopping-cart sign), and tolerance of flexion-based activity such as a stationary bike.
Preserved, symmetric pulses argue against a vascular cause and point to a neurogenic mechanism.
MRI is the diagnostic test of choice; it directly demonstrates central canal, lateral recess, and neural foraminal narrowing along with the contributing soft-tissue changes such as ligamentum flavum thickening, facet hypertrophy, and disc bulging.
Why the others are wrong
Lumbar spine CT scan: CT shows bone well but resolves the neural elements and soft tissue poorly; it is reserved as a CT myelogram alternative only when MRI is contraindicated, so it is not the first-choice study here.
Lumbar spine x-rays: flexion-extension films can detect dynamic spondylolisthesis but do not visualize the neural canal or soft tissue, making them adjunctive rather than the primary study to confirm stenosis.
Ankle-brachial index: this screens for peripheral arterial disease, but posture-dependent relief and intact symmetric pulses make vascular claudication unlikely, so it is not the discriminating next test.
EMG of lower extremities — the slightly diminished ankle reflexes may raise concern for peripheral neuropathy or radiculopathy, but electrodiagnostic testing assesses nerve and muscle physiology and cannot show the canal or foraminal narrowing that defines lumbar spinal stenosis; it is an adjunct when a competing neuropathy is suspected.
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Combination of disc bulging, facet hypertrophy, ligamentum flavum thickening, and osteophyte formation narrows the canal and neural foramina. Standing and lumbar extension further reduce canal diameter, compressing neural elements and causing symptoms. Flexion (sitting, leaning forward) increases canal area and relieves symptoms.
Clinical presentation
Symptoms
Bilateral or unilateral leg pain, numbness, or weakness with walking or standing
Symptoms relieved by sitting, leaning forward, or flexing the spine ('shopping cart sign')
Better walking uphill or pushing a cart (flexed posture); worse walking downhill or standing erect
Back pain often less prominent than leg symptoms
Symptoms progress over months to years
Signs / physical exam
Often unremarkable when supine — examination after walking can reproduce symptoms
Wide-based gait, reduced lumbar extension
Mild distal weakness or hyporeflexia may be present
Pulses preserved (helps differentiate from vascular claudication)
Romberg testing may be positive in advanced disease
Differential diagnosis
Vascular claudication (PAD) — Pain calf > thigh, relieved by standing still (not posture change), reduced pulses, ABI ≤0.90
Hip osteoarthritis — Groin pain reproduced by hip motion, FABER positive
Diabetic peripheral neuropathy — Symmetric stocking distribution, sensory loss, normal back exam
NSAIDs — ibuprofen, naproxen, meloxicam — commonly used for short-term symptom relief alongside PT, though LSS-specific trial evidence is limited
Acetaminophen as adjunct
Second-line / adjunct
Epidural steroid injections — little or no benefit over anesthetic injection alone for neurogenic claudication (LESS trial); may be tried selectively for a dominant radicular component
Avoid chronic opioids
Surgical decompression (laminectomy) — for patients with persistent disabling symptoms despite conservative care; greater short-to-medium-term benefit than non-operative care in selected patients
Fusion added when associated spondylolisthesis or significant instability
Gabapentinoids (gabapentin, pregabalin) — little evidence of benefit for neurogenic claudication; not recommended routinely (Bussières 2021)
Complications
Progressive functional decline, falls, deconditioning
The 'shopping cart sign' — relief while leaning forward over a cart — is one of the most useful historical clues.
Walking distance is preserved or even better with hills/uphill (flexion); reduced with downhill walking (extension).
Preserved peripheral pulses help differentiate neurogenic from vascular claudication; check ABI when in doubt.
Conservative management is reasonable indefinitely if symptoms are tolerable — decompression is for refractory disabling disease.
Always reassess for cauda equina warning signs in any patient with known stenosis.
References
NASS 2011/2013 — NASS Evidence-Based Clinical Guidelines: Diagnosis and Treatment of Degenerative Lumbar Spinal Stenosis (Kreiner et al., Spine J 2013)
LSS CPG 2021 — Non-Surgical Interventions for Lumbar Spinal Stenosis Leading to Neurogenic Claudication: A Clinical Practice Guideline (Bussières A et al., J Pain 2021;22:1015-1039)
SPORT Trial — Surgical vs Non-operative Treatment for Lumbar Spinal Stenosis (Weinstein et al., NEJM 2008)
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