Lumbar Spinal Stenosis
High Yield Overview
Lumbar Spinal Stenosis
Canal narrowing causing leg symptoms with walking - relieved by flexion (shopping cart sign)
L4-5Most commonly affected level
80%SPORT trial surgery success rate
11mmAbsolute stenosis threshold (AP)
60+Peak age (years)
Lumbar Stenosis Classification
Critical Must-Knows
- Neurogenic vs vascular claudication: neurogenic relieved by FLEXION, vascular by stopping
- Shopping cart sign: patient prefers flexed position (opens canal)
- Absolute stenosis: less than 10mm AP diameter, relative: 10-12mm
- SPORT trial: surgery superior at 2-4 years for symptomatic stenosis
- Add fusion if instability or spondylolisthesis present
Examiner's Pearls
- "Often normal neurological examination at rest - symptoms reproduced with walking
- "Wide-based gait and forward-flexed posture are classic
- "L4-5 most commonly affected level followed by L3-4
- "MRI is gold standard - CT myelogram if MRI contraindicated
Clinical Imaging
Imaging Gallery
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Exam Warning
The key clinical distinction is NEUROGENIC vs VASCULAR claudication! Neurogenic: leg symptoms with walking, relieved by FLEXION (shopping cart sign). Vascular: calf pain, relieved by stopping (not necessarily flexing). Examiners love this distinction!
At a Glance
| Aspect | Key Information |
|---|---|
| Definition | Canal narrowing causing neural compression |
| Peak age | 60-70 years (degenerative) |
| Most common level | L4-5, then L3-4 |
| Cardinal symptom | Neurogenic claudication |
| Classic history | Pain with walking, relief with sitting/bending forward |
| Key sign | Shopping cart sign (flexion preference) |
| Imaging | MRI gold standard |
| Absolute stenosis | Under 11mm AP canal diameter |
| Surgery | Laminectomy plus/minus fusion |
Mnemonic
NARROWLumbar Stenosis Key Features
N
Neurogenic claudication
Leg symptoms with walking, relieved by sitting
A
Age over 60
Peak incidence in 6th-7th decade
R
Relief with flexion
Shopping cart sign - better bending forward
R
Radiculopathy possible
Root compression causes dermatomal symptoms
O
Often L4-5 level
Most commonly affected level (80%)
W
Walking distance reduced
Progressive decrease in claudication distance
Memory Hook:The canal gets NARROW!
Mnemonic
FLEXEDStenosis vs Vascular Claudication
F
Flexion relieves
Sitting/bending forward increases canal diameter
L
Legs bilateral
Typically affects both legs, buttocks, thighs
E
Extension worsens
Standing/walking with extension narrows canal
X
X-ray normal pulses
Peripheral pulses preserved (unlike vascular)
E
Exercise tolerance varies
Cycling tolerated well (flexed position)
D
Degenerative cause
Disc bulge, facet hypertrophy, ligamentum flavum
Memory Hook:Neurogenic = FLEXED position helps!
Mnemonic
NVCDNeurogenic vs Vascular Claudication
N
Neurogenic
Position-dependent, better sitting/flexed
V
Vascular
Distance-dependent, need to stop walking
C
Cart sign
Leaning on shopping cart suggests neurogenic
D
Different pulses
Intact pulses = neurogenic, absent = vascular
Memory Hook:Neurogenic: Cart helps. Vascular: Circulation problem!
Mnemonic
SILLFusion Indications in Lumbar Stenosis
S
Spondylolisthesis
Slip requires stabilization
I
Instability
Dynamic on flexion-extension views
L
Loss of sagittal balance
Significant deformity
L
Large decompression
Extensive facetectomy destabilizes
Memory Hook:SILL patients need fusion for STability!
Mnemonic
CESSCauda Equina Syndrome
C
Coordination loss
Bilateral leg weakness
E
Emptying problems
Bladder retention or incontinence
S
Saddle anesthesia
Perineal numbness
S
Sexual dysfunction
May be present
Memory Hook:CESS = Surgical Emergency, don't wait!
Overview and Epidemiology
Lumbar spinal stenosis (LSS) is one of the most common causes of low back and leg symptoms in older adults. It represents progressive narrowing of the spinal canal leading to compression of neural elements.
Epidemiology
Prevalence and Demographics
| Parameter | Value |
|---|---|
| Prevalence | 20-30% in population over 60 (imaging) |
| Symptomatic | 5-10% of those with imaging stenosis |
| Peak age | 60-70 years |
| Gender | Equal or slight male predominance |
| Most common surgical indication | Number one reason for spine surgery in patients over 65 |
Most Affected Levels
- L4-5: Most commonly affected (80%)
- L3-4: Second most common
- Multi-level: Common in advanced disease
- L5-S1: Less common (protected by iliolumbar ligament)
Pathophysiology
Canal Anatomy
Normal Dimensions
| Parameter | Normal Value | Stenosis Threshold |
|---|---|---|
| AP diameter | 15-18mm | Under 11mm (absolute) |
| Lateral diameter | 20-25mm | Under 15mm |
| Cross-sectional area | 200-400mm2 | Under 100mm2 (severe) |
| Lateral recess | 5-7mm | Under 3mm (stenosis) |
| Foramen height | 20-23mm | Under 15mm |
Stenosis Types
| Type | Location | Structures Affected | Clinical Pattern |
|---|---|---|---|
| Central | Spinal canal | Cauda equina | Bilateral claudication |
| Lateral recess | Between pedicle and facet | Traversing root | Radiculopathy pattern |
| Foraminal | Neural foramen | Exiting root | Radiculopathy pattern |
| Far lateral | Beyond foramen | Exiting root | Often missed on imaging |
Pathophysiology
Contributing Factors to Stenosis
| Structure | Contribution | Mechanism |
|---|---|---|
| Disc | Anterior narrowing | Bulging, height loss |
| Facets | Posterolateral narrowing | Hypertrophy, arthrosis |
| Ligamentum flavum | Posterior narrowing | Hypertrophy, infolding |
| Pedicles | Lateral narrowing | Congenital short pedicle |
| Spondylolisthesis | Dynamic narrowing | Forward translation |
Pathophysiology of Symptoms
| Mechanism | Effect |
|---|---|
| Mechanical compression | Direct neural compression |
| Venous congestion | Impaired venous drainage, edema |
| Arterial ischemia | Reduced blood flow during exercise |
| Inflammatory mediators | Chemical irritation of nerves |
Exam Pearl
Why flexion helps: Flexion INCREASES canal diameter (ligamentum flavum stretches, foramina open). Extension DECREASES canal diameter (ligamentum flavum buckles, foramina narrow). This explains the "shopping cart sign" - patients prefer flexion!
Classification Systems
Anatomical Classification
| Type | Structures | Symptoms |
|---|---|---|
| Central stenosis | Canal narrowing | Bilateral claudication, diffuse leg symptoms |
| Lateral recess stenosis | Anterolateral gutter | Radiculopathy, unilateral or asymmetric |
| Foraminal stenosis | Neural foramen | Radiculopathy, dermatomal pattern |
| Combined | Multiple areas | Mixed symptoms |
Clinical Presentation
History
Cardinal Symptom: Neurogenic Claudication
| Feature | Description |
|---|---|
| Onset | With walking or prolonged standing |
| Location | Buttocks, thighs, legs (often bilateral) |
| Character | Heaviness, burning, aching, cramping |
| Relief | Sitting, bending forward (flexion) |
| Walking distance | Progressively shortened |
Key History Questions
- Walking distance before symptoms (claudication distance)
- Relief with flexion (sitting, leaning forward)
- Cycling tolerance (usually good - flexed position)
- Ascending vs descending stairs (descending often worse - extension)
- Back pain component (may be less prominent than leg symptoms)
- Bowel/bladder symptoms (cauda equina screening)
Mnemonic
WALKINGCLAUDICATION Symptoms
W
Walking
Symptoms develop with walking
A
Aching
Aching, heaviness in legs
L
Legs bilaterally
Usually bilateral leg symptoms
K
Killed by flexion
Relieved by bending forward
I
Improving with rest
Improves with sitting
N
Not just calves
Buttocks and thighs affected (vs vascular)
G
Gradually worsening
Progressive reduction in walking distance
Memory Hook:Symptoms that come with WALKING!
Neurogenic vs Vascular Claudication
Claudication Differentiation
| Feature | Neurogenic | Vascular |
|---|---|---|
| Location | Buttocks, thighs, diffuse | Calves primarily |
| Onset | With walking OR standing | With walking only |
| Relief | Sitting/flexing forward | Standing still |
| Time to relief | Variable, may take minutes | Rapid (1-2 minutes) |
| Cycling | Usually tolerated well | May provoke symptoms |
| Shopping cart sign | Positive (prefers flexion) | Negative |
| Pulses | Normal | May be diminished |
| Walking uphill | Often better | Worse |
| Walking downhill | Often worse | Better |
Clinical Examination Findings
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Physical Examination
General Observation
- Wide-based, shuffling gait
- Forward-flexed posture (simian stance)
- Uses assistive devices
Lumbar Spine Examination
| Test | Technique | Finding in Stenosis |
|---|---|---|
| ROM | Flexion/extension | Extension often limited or provocative |
| Extension test | Maintain extension 30 seconds | May reproduce leg symptoms |
| Stoop test | Walk then stop flexed | Longer walking if allowed to flex |
| Bicycle test | Cycling (flexed) | Better tolerance than walking |
Neurological Examination
| Component | Findings | Notes |
|---|---|---|
| Motor | Often normal at rest | May develop weakness after walking |
| Sensory | May have patchy changes | Multi-dermatomal in central stenosis |
| Reflexes | Variable, may be diminished | L4 (knee jerk), S1 (ankle jerk) |
| Pulses | Normal | Important to document (exclude vascular) |
Mnemonic
SHOPNeurogenic Claudication Signs
S
Shopping cart sign
Prefers flexion, leans on cart
H
Hills - uphill better
Uphill walking (flexed) tolerated better
O
Onset with extension
Extension reproduces symptoms
P
Pulses preserved
Normal peripheral pulses (not vascular)
Memory Hook:They prefer to SHOP (use a cart)!
Investigations
Imaging Algorithm
Standard Approach
| Step | Investigation | Purpose |
|---|---|---|
| 1 | Weight-bearing X-rays | Alignment, instability, spondylolisthesis |
| 2 | MRI lumbar spine | Canal dimensions, soft tissue, neural compression |
| 3 | CT (if needed) | Bony detail, surgical planning |
| 4 | CT myelogram | MRI contraindicated, dynamic assessment |
Plain Radiographs
Key Findings
- Disc space narrowing
- Facet arthropathy
- Spondylolisthesis (dynamic films if suspected)
- Scoliosis
- Sagittal alignment
Flexion-Extension Views
- Instability: Over 3-4mm translation or over 10-15 degrees angular change
- Important for surgical planning (fusion decision)
MRI Findings
| Finding | Description | Significance |
|---|---|---|
| CSF obliteration | Loss of CSF signal around cauda | Indicates compression |
| Disc bulge | Concentric disc expansion | Anterior canal narrowing |
| Ligamentum flavum | Hypertrophy on T1/T2 | Posterior canal narrowing |
| Facet hypertrophy | Enlarged facet joints | Lateral narrowing |
| Nerve root crowding | Roots pressed together | Severe stenosis |
| Fat obliteration | Loss of epidural fat | Canal compromise |
MRI Grading (Schizas Classification)
| Grade | Description |
|---|---|
| A | CSF visible, nerve roots separated |
| B | Nerve roots starting to aggregate |
| C | Nerve roots not separable, some CSF visible |
| D | No CSF visible, severe compression |
Exam Pearl
Imaging-Clinical Correlation: Many patients have radiographic stenosis but are asymptomatic. Always correlate imaging with clinical symptoms. The level of maximum stenosis should match the clinical syndrome!
MRI Examples
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Additional Investigations
| Test | Indication | Information |
|---|---|---|
| EMG/NCS | Unclear diagnosis, radiculopathy vs neuropathy | Localizes nerve dysfunction |
| ABI (Ankle-Brachial Index) | Suspected vascular claudication | Under 0.9 suggests PVD |
| Bone scan | Suspected tumor, infection | Uptake pattern |
| DEXA | Osteoporosis assessment | Guides fusion considerations |
Management
📊 Management Algorithm
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Conservative Treatment
Duration: 6-12 weeks trial, may continue if improving
Activity Modification
Flexion-based activities (cycling, swimming). Avoid prolonged extension. Rest breaks during walking. Walking aids if needed. Weight loss if applicable.
Pharmacotherapy
First-line: Paracetamol, NSAIDs (short course). Second-line: Gabapentin/pregabalin for neuropathic component. Muscle relaxants for acute spasm. Avoid: Prolonged opioids.
Physical Therapy
Flexion-based exercises (Williams flexion). Core strengthening. Aerobic conditioning. Postural training. Manual therapy. Aquatic therapy excellent.
Epidural Injections
Lumbar epidural steroid injection. Interlaminar or transforaminal approach. Short-term benefit (weeks to months). May delay surgery in some patients. Diagnostic value for surgical planning.
Complications
Conservative Treatment Complications
| Complication | Cause | Prevention |
|---|---|---|
| Disease progression | Natural history | Monitor symptoms |
| Deconditioning | Activity avoidance | Encourage exercise |
| NSAID gastropathy | Prolonged use | PPI cover, limit duration |
| Opioid dependence | Chronic use | Avoid prolonged opioids |
Surgical Complications
| Complication | Rate | Management |
|---|---|---|
| Dural tear | 5-10% | Primary repair, fibrin glue |
| CSF leak | 2-5% | Bed rest, blood patch if needed |
| Infection | 1-3% | Antibiotics, debridement if deep |
| Neurological injury | 0.5-1% | Prevent with careful technique |
| Instability | 5-10% (late) | Fusion if symptomatic |
| Recurrent stenosis | 10-15% at 10 years | Revision surgery |
| Adjacent segment disease | 2-3% per year (if fused) | Surveillance, may need extension |
Mnemonic
DURALLaminectomy Complications
D
Dural tear
Most common intraop complication (5-10%)
U
Unstable spine
Instability if too much facet removed
R
Recurrence
Recurrent stenosis at same or adjacent level
A
Adhesions
Epidural fibrosis causing symptoms
L
Leaky CSF
CSF leak requiring treatment
Memory Hook:Protect the DURAL sac!
Postoperative Care
Laminectomy Protocol
Immediate (Day 0-2)
- Mobilize day 0-1 (walking)
- DVT prophylaxis
- Pain management (multimodal)
- Wound check daily
- Neurological monitoring
Early (Weeks 1-6)
- Wound check at 2 weeks
- Gradually increase activity
- No bending, lifting, twisting initially
- Walking encouraged
- Physiotherapy referral at 4-6 weeks
Intermediate (Weeks 6-12)
- Progressive strengthening
- Return to sedentary work 4-6 weeks
- Return to manual work 8-12 weeks
- Full activity by 3 months
Expected Recovery
| Symptom | Recovery Pattern |
|---|---|
| Leg pain | Often immediate improvement |
| Walking distance | Progressive improvement over weeks |
| Back pain | May take longer to improve |
| Numbness | Variable, may not fully resolve |
| Weakness | Gradual improvement if preoperative deficit |
Evidence Base
Natural History
- Progressive decline in walking distance
- Neurological deterioration in minority
- Some patients stable for years
- Rarely causes complete paralysis
Evidence Base
SPORT Trial - Spinal Stenosis
Weinstein JN et al. • NEJM (2008)
Key Findings:
- RCT comparing surgery vs conservative for lumbar stenosis
- Intention-to-treat: No significant difference (high crossover rate)
- As-treated analysis: Surgery significantly better
- Surgery patients: 80% improved at 2 years
- Conservative: 60% improved at 2 years
- Benefit maintained at 4 year follow-up
Clinical Implication: Landmark trial showing surgical benefit - understand both ITT and as-treated results
SPORT Trial - Long-term Follow-up
Weinstein JN et al. • Spine (2010)
Key Findings:
- 4-year outcomes from SPORT stenosis cohort
- Surgical benefit maintained at 4 years
- NDI improvement significant in surgical group
- SF-36 bodily pain improved significantly
- High crossover rate limits interpretation
Clinical Implication: Long-term durability of surgical benefit
Minimally Invasive vs Open Laminectomy
Phan K, Mobbs RJ • Eur Spine J (2016)
Key Findings:
- Systematic review of MIS vs open decompression
- Similar clinical outcomes at 2 years
- MIS: Less blood loss, shorter hospital stay
- MIS: Longer operative time, learning curve
- No difference in complication rates
Clinical Implication: Evidence supporting MIS as alternative in appropriate patients
Interspinous Spacer Devices
Moojen WA et al. • Lancet (2013)
Key Findings:
- RCT comparing X-STOP to brace in neurogenic claudication
- X-STOP failed to show superiority over brace at 2 years
- High reoperation rate for X-STOP (29%)
- Questions role of interspinous devices
- May delay but not replace definitive surgery
Clinical Implication: Evidence questioning role of interspinous devices
Epidural Steroid Injections for Lumbar Stenosis
Friedly JL et al. • NEJM (2014)
Key Findings:
- RCT comparing epidural steroid vs lidocaine alone for stenosis
- No significant difference in outcomes at 6 weeks
- Both groups showed modest improvement
- Steroids added minimal benefit over anesthetic alone
- Questions routine use of steroids in epidurals for stenosis
Clinical Implication: Important evidence questioning role of steroids in epidural injections
Differential Diagnosis
Differential Diagnosis of Lumbar Stenosis
| Condition | Distinguishing Features | Investigation |
|---|---|---|
| Vascular claudication | Calf pain, absent pulses, rapid relief with standing | ABI, Doppler, angiography |
| Hip osteoarthritis | Groin pain, limited hip ROM, FABER positive | Hip X-ray, MRI hip |
| Peripheral neuropathy | Stocking-glove distribution, diabetic history | EMG/NCS, glucose, B12 |
| Lumbar disc herniation | Radicular pattern, positive SLR, younger patient | MRI shows focal disc |
| Sacroiliac dysfunction | Buttock pain, positive SI tests, FABER pain | SI X-rays, CT, injection |
| Cauda equina syndrome | Bladder/bowel dysfunction, saddle anesthesia | Urgent MRI |
| Piriformis syndrome | Buttock pain, positive piriformis tests | Clinical, MRI may show muscle |
| Spinal tumor | Night pain, constitutional symptoms, progressive | MRI with contrast |
References
- Weinstein JN, et al. Surgical versus nonsurgical therapy for lumbar spinal stenosis. NEJM 2008;358:794-810.
- Weinstein JN, et al. SPORT lumbar stenosis: four-year results. Spine 2010;35:1329-38.
- Phan K, Mobbs RJ. Minimally invasive versus open laminectomy for lumbar stenosis. Eur Spine J 2016;25:654-65.
- Moojen WA, et al. Effectiveness of interspinous implant surgery in patients with intermittent neurogenic claudication. Lancet 2013;381:1199-206.
- Verbiest H. A radicular syndrome from developmental narrowing of the lumbar vertebral canal. J Bone Joint Surg Br 1954;36:230-7.
- Amundsen T, et al. Lumbar spinal stenosis: conservative or surgical management? Spine 2000;25:1424-35.
- Malmivaara A, et al. Surgical or nonoperative treatment for lumbar spinal stenosis? Spine 2007;32:1-8.
- Kreiner DS, et al. An evidence-based clinical guideline for the diagnosis and treatment of lumbar disc herniation with radiculopathy. Spine J 2014;14:180-91.
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
VIVA SCENARIOStandard
Scenario 1: Classic Neurogenic Claudication
EXAMINER
"What is your diagnosis and management approach?"
EXCEPTIONAL ANSWER
This is neurogenic claudication secondary to L4-5 lumbar spinal stenosis. Classic features include limited walking distance (100m), relief with flexion (shopping cart sign), leg symptoms predominating over back pain, and MRI confirming stenosis. To differentiate from vascular claudication: neurogenic is relieved by flexion not just stopping, cycling is comfortable, uphill walking is better, and pulses are normal. Vascular causes calf pain, relief within 1-2 minutes of stopping, diminished pulses. For conservative treatment, I would offer flexion-based exercises (Williams flexion program), short-course NSAIDs with gastroprotection, physiotherapy for core strengthening and aquatic exercise, walking aids, and epidural steroid injection. Trial conservative management for 6-12 weeks before surgery. Surgical indications: failure of conservative care, significant functional limitation, progressive symptoms, patient preference. I would offer L4-5 laminectomy without fusion since there is no instability or spondylolisthesis.
KEY POINTS TO SCORE
Classic neurogenic claudication: shopping cart sign, relief with flexion, leg greater than back pain
Key differentiation: neurogenic relieved by flexion, vascular by rest in any position
Conservative trial 6-12 weeks before surgery unless red flags
L4-5 laminectomy without fusion if no instability
COMMON TRAPS
✗Missing vascular claudication in differential - always check pulses
✗Rushing to surgery without adequate conservative trial
✗Not considering epidural injection as bridge to surgery
✗Adding fusion when there is no instability or spondylolisthesis
LIKELY FOLLOW-UPS
"What are the differences in symptom relief timing between neurogenic and vascular claudication?"
"What is the evidence for epidural steroid injections in lumbar stenosis?"
"How would your approach change if she had Grade 1 spondylolisthesis?"
"What are the expected outcomes after laminectomy for stenosis?"
VIVA SCENARIOStandard
Scenario 2: Stenosis with Spondylolisthesis
EXAMINER
"How does spondylolisthesis affect your surgical planning?"
EXCEPTIONAL ANSWER
Grade 1 degenerative spondylolisthesis adds complexity as it suggests segmental instability and contributes to stenosis. The key question is whether fusion is needed in addition to decompression. For stability assessment, 2mm dynamic translation is STABLE (under 3-4mm threshold) and Grade 1 (25% slip) is low grade. However, dynamic flexion-extension views suggest some motion - this is a borderline case for fusion. Given failed conservative treatment and borderline stability, I would recommend laminectomy with posterolateral or interbody fusion. Fusion options include: (1) Posterolateral fusion (PLF) with pedicle screws, (2) PLIF for better sagittal correction, or (3) TLIF with unilateral approach and less retraction. Choice depends on surgeon preference and patient factors. All require adequate decompression first.
KEY POINTS TO SCORE
Grade 1 spondylolisthesis contributes to stenosis
2mm translation is stable (threshold 3-4mm)
Consider fusion for spondylolisthesis even if stable
Options: PLF, PLIF, TLIF - all require decompression first
COMMON TRAPS
✗Performing laminectomy alone with spondylolisthesis risks instability progression
✗Not assessing dynamic stability with flexion-extension films
✗Forgetting that Grade 1 is 25% slip (not percentage)
LIKELY FOLLOW-UPS
"What are the differences between PLIF and TLIF?"
"At what grade of spondylolisthesis would you definitely add fusion?"
"What are the complications of instrumented fusion?"
VIVA SCENARIOStandard
Scenario 3: Multilevel Stenosis
EXAMINER
"What are the surgical considerations for multilevel stenosis in this high-risk patient?"
EXCEPTIONAL ANSWER
4-level decompression is extensive surgery with higher blood loss, longer operative time, and greater risk of instability if facets are compromised. Need to decompress all symptomatic levels but can prioritize based on clinical correlation. Consider staging if very high risk. For fitness assessment: cardiology review given previous stent (assess timing since stent, antiplatelet management), NYHA functional class, diabetic control (HbA1c), renal function, ASA grade. May need stress testing or echocardiogram. Optimize medical conditions preoperatively. MIS laminotomy can be performed at multiple levels with less blood loss and shorter hospital stay, though with longer operative time and learning curve. For high-risk patients, alternatives include: targeted decompression at most stenotic level only, epidural injections for palliation, interspinous spacers at 1-2 levels (limited evidence), or conservative management with walking aids. Discuss goals of care openly.
KEY POINTS TO SCORE
4-level decompression has higher blood loss and instability risk
Cardiology review essential for cardiac stent patient
Consider MIS for reduced surgical stress
Can prioritize most symptomatic levels or stage surgery
COMMON TRAPS
✗Proceeding with major surgery without adequate medical optimization
✗Not correlating imaging stenosis with clinical symptoms
✗Forgetting antiplatelet management in cardiac stent patient
✗Missing the option to stage surgery in very high-risk patients
LIKELY FOLLOW-UPS
"How long after cardiac stent should you wait before elective surgery?"
"What are the advantages of MIS in high-risk patients?"
"How would you counsel this patient about surgical risks?"
MCQ Practice Points
High-Yield Concepts
- Neurogenic vs vascular claudication: Neurogenic relieved by FLEXION, vascular by stopping
- Shopping cart sign: Preference for flexed posture (opens canal)
- L4-5 most common level for degenerative stenosis
- Absolute stenosis: Under 11mm AP diameter (under 100mm2 area)
- SPORT trial: Surgery superior in as-treated analysis
- Fusion indication: Spondylolisthesis, instability, more than 50% facetectomy
- Dural tear: Most common intraoperative complication (5-10%)
Common Examination Pitfalls
- Confusing neurogenic and vascular claudication
- Missing spondylolisthesis on imaging (need to look for it)
- Forgetting to assess stability with flexion-extension views
- Not correlating imaging stenosis with clinical symptoms
- Overlooking cauda equina red flags
Australian Context
PBS-Subsidized Medications
| Medication | PBS Status | Notes |
|---|---|---|
| Paracetamol | General listing | First-line |
| NSAIDs | General listing | Short-term use recommended |
| Gabapentin | Restricted (chronic pain) | Authority required |
| Pregabalin | Restricted (neuropathic) | S8, authority required |
eTG Recommendations
- Initial trial of conservative management
- Activity modification and physiotherapy
- NSAIDs short term with gastroprotection
- Specialist referral for surgical consideration after failed conservative care
Australian Practice Points
- Public hospital waiting times: Often 6-12 months for elective spinal surgery
- Private practice: Typically 2-6 weeks
- Enhanced Recovery After Spine Surgery (ERAS) protocols increasingly adopted
- Telehealth follow-up common in regional areas
Exam Day Cheat Sheet
MCQ Practice Points
Neurogenic vs Vascular Claudication
Q: What are the key distinguishing features between neurogenic and vascular claudication? A: Neurogenic claudication (lumbar stenosis): Relieved by sitting or bending forward (shopping cart sign), proximal-to-distal symptoms, walking distance variable, pulses present. Vascular claudication (PVD): Relieved by standing still, distal-to-proximal symptoms, fixed walking distance, pulses absent/diminished. Bicycle test positive for neurogenic (can cycle indefinitely in flexion) and limited for vascular.
Absolute Stenosis Measurements
Q: What defines absolute lumbar spinal stenosis on imaging? A: Absolute stenosis: AP diameter less than 10mm OR cross-sectional area less than 100mm². Relative stenosis: AP diameter 10-13mm or area 100-130mm². Central canal, lateral recess (less than 3mm), and foraminal (less than 3mm height) can all be involved. MRI is gold standard for assessment.
Surgical Indications
Q: What are the surgical indications for lumbar spinal stenosis? A: Surgery is indicated for: Failed conservative management (6-12 weeks minimum trial), progressive neurological deficit, cauda equina syndrome (emergency), and intractable pain affecting quality of life. The SPORT trial showed surgery provides faster improvement than conservative care, though outcomes converge at 2-4 years.
Decompression Options
Q: What are the surgical options for lumbar stenosis and when is fusion required? A: Decompression alone: Stable spine, single/multi-level stenosis without instability. Decompression plus fusion: Spondylolisthesis greater than Grade 1, evidence of segmental instability, iatrogenic destabilization, recurrent stenosis. Fusion adds morbidity but may be required for mechanical back pain or significant listhesis.
Australian Context
Clinical Guidelines: Lumbar spinal stenosis is managed according to RACS and Australian Spine Society guidelines. Initial conservative management (physiotherapy, analgesia) is recommended for 6-12 weeks before surgical consultation. Imaging with MRI is standard for surgical planning.
PBS-Subsidised Medications: First-line analgesia includes paracetamol and NSAIDs (ibuprofen, naproxen) available over-the-counter or PBS-subsidised. Neuropathic agents (pregabalin, gabapentin) are PBS-listed for chronic neuropathic pain following failed first-line therapy.
Surgical Management: Lumbar decompression is performed by spine surgeons in public and private hospitals. Complex cases requiring fusion are typically managed at tertiary centres with spinal fellowship-trained surgeons.
Rehabilitation: Post-operative physiotherapy is available through Enhanced Primary Care (EPC) plans with Medicare rebates. Inpatient rehabilitation may be required for elderly or deconditioned patients following surgery.
Lumbar Spinal Stenosis
High-Yield Exam Summary
Key Definitions
- •Canal narrowing causing neural compression and neurogenic claudication
- •Absolute stenosis: Under 11mm AP diameter or under 100mm2 cross-sectional area
- •Types: Central, lateral recess, foraminal, or combined stenosis
- •Etiology: Degenerative (most common), congenital, post-traumatic, iatrogenic
Clinical Features
- •Most common level: L4-5 (80%), then L3-4
- •Cardinal symptom: Neurogenic claudication - leg symptoms with walking, relieved by flexion
- •Key sign: Shopping cart sign - prefers flexion (opens canal)
- •Extension worsens symptoms - ligamentum flavum buckles, foramina narrow
Neurogenic vs Vascular Claudication
- •Neurogenic: flexion relief, better uphill, can cycle, normal pulses
- •Vascular: standing still relief, calf pain, worse uphill, diminished pulses
- •Neurogenic relief timing: Variable (minutes); Vascular: rapid (1-2 min)
- •Both: Progressive reduction in walking distance
Imaging
- •First-line: MRI - shows canal dimensions, soft tissue, neural compression
- •Flexion-extension films: Assess for instability (over 3-4mm translation)
- •Schizas grading: A (mild) to D (severe) based on CSF and root visibility
- •CT myelogram: Alternative if MRI contraindicated, excellent bony detail
Management
- •Conservative Rx: Flexion exercises, NSAIDs, physio, epidurals; trial 6-12 weeks
- •Surgery indication: Failed conservative Rx, functional limitation, progressive deficit
- •Standard surgery: Laminectomy (preserve over 50% facet to avoid instability)
- •Add fusion if: Spondylolisthesis, instability, over 50% facetectomy
Evidence and Complications
- •SPORT trial: Surgery superior in as-treated analysis; 80% improved at 2-4 years
- •Dural tear: Most common intraop complication (5-10%); primary repair with fibrin glue
- •Recurrent stenosis: 10-15% at 10 years may need revision
- •Adjacent segment disease: 2-3% per year if fused