High-yield overview
Axial Neck Pain | Diagnosis by Blockade | Radiofrequency Ablation Treatment
55%Chronic Neck Pain Cause
60%Whiplash Prevalence
C2/3Most Common Level
80%Relief Required (MBB)
Diagnostic Criteria (Bogduk)
Pain Pattern
PatternAxial neck pain (No Radiculopathy). Referred patterns to head/shoulder.
TreatmentClinical Suspicion
Block 1
PatternPositive response (greater than 80% relief) to Medial Branch Block
TreatmentScreening
Block 2
PatternPositive response to Confirmatory Block (Different day/agent)
TreatmentConfirmation
Critical Must-Knows
- Facet joints (Z-joints) are the most common source of chronic neck pain after whiplash.
- Pain is typically AXIAL and NON-RADICULAR (Referral zones exist but do not follow dermatomes).
- Degenerative changes on X-ray/CT do NOT correlate well with pain (False positives common).
- Diagnosis CANNOT be made by history/exam alone - requires Diagnostic Blocks (MBB).
- Treatment of choice for confirmed cases is Radiofrequency Neurotomy (RFA).
Clinical Pearls
- “C2/3 Facet refers pain to the Occiput (Cervicogenic Headache).
- “C5/6 Facet refers pain to the shoulder/scapula.
- “Pain is worse with Extension and Rotation (Loading the facet).
- “Single uncontrolled block has a high false-positive rate (around 27%) - hence double blocking is the Gold Standard.
Clinical Imaging
Imaging Atlas
Diagnostic Pitfalls
Imaging Fallacy
Treat the patient, not the scan. Severe OA on X-ray does NOT mean the joint is painful. Normal joints CAN be painful (post-whiplash).
Radiculopathy Exclusion
Rule out radiculopathy. If arm pain exceeds neck pain or a neuro deficit is present, the Nerve Root is the suspect, not the Facet.
False Positive Blocks
False-positive rate of a single block is about 27% (placebo, systemic spread). Sedation invalidates results. A Pain Diary is essential.
At a Glance
| Feature | Facet Joint (Z-Joint) | Discogenic Pain | Radiculopathy |
|---|---|---|---|
| Primary Pain | Neck (Axial) | Neck (Axial) | Arm (Radicular) |
| Aggravation | Extension / Rotation | Flexion / Loading | Extension / Spurling's |
| Referral | Somatic (Head/Scapula) | Somatic (Interscapular) | Dermatomal (Hand) |
| Deficits | None | None | Motor/Sensory Loss |
Mnemonics
Mnemonic
FACETFacet Features
F
False Positives
High rate on single block
A
Axial
Pain is axial, not radicular
C
Cervicogenic
C2/3 causes headache
E
Extension
Worsens pain
T
Two Blocks
Required for diagnosis
Hook:Key clinical features.
Mnemonic
SAME + ABOVEInnervation Rule
S
Same
Medial branch of SAME level
A
Above
Medial branch of level ABOVE
Hook:Each joint has dual innervation. (e.g. C5/6 joint is supplied by C5 and C6 medial branches).
Mnemonic
WADWhiplash Rule
W
Women
Higher risk
A
Axial
Pain pattern
D
Delayed
Onset can be 24-48hrs
Hook:Epidemiology of facet trauma.
Overview & Epidemiology
Definition: Pain arising from the cervical zygapophysial (facet) joints, typically axial and non-radicular. Diagnosis is made by response to controlled medial branch blocks, not by imaging.
Epidemiology
- Most common identifiable source of chronic neck pain after whiplash (around 60% of cases; Lord 1996).
- C2/3 and C5/6 are the most frequently involved levels.
- Female predominance; onset often delayed 24-48 hours after a motor-vehicle deceleration injury.
- Neck pain overall is a leading global cause of years lived with disability.
Why it matters: Degenerative facet change on imaging is near-universal with age and correlates poorly with pain, so a structured block-based pathway is essential before committing to ablation.
Pathophysiology and Mechanisms
Facet Joint Structure
- Synovial joint.
- Oriented at 45 degrees in the coronal plane.
- Resists anterior translation and rotation.
Innervation (Crucial for RFA)
- Each joint is innervated by the Medial Branch of the dorsal ramus.
- Dual Innervation: Each joint receives branches from the level above and the same level.
- Example: C4/5 joint is supplied by C4 and C5 medial branches.
- Exception: C2/3 joint is supplied by the Third Occipital Nerve (TON) and C2 medial branch.
Pain Referral Patterns (Bogduk Maps)
- C2/3: Occiput, Mastoid (Headache).
- C3/4: Upper neck.
- C5/6: Lower neck, Trapezius ridge, Acromion.
- C6/7: Scapula border.
Classification Systems
IASP / Bogduk Diagnostic Criteria
Classification relies on response to diagnostic blocks, not imaging.
- Possible Facet Pain: History and Exam suggestive. Imaging shows OA.
- Probable Facet Pain: Greater than 80% relief from a SINGLE Medial Branch Block (MBB).
- Definite Facet Pain: Greater than 80% relief from TWO comparative blocks (e.g. Lignocaine then Bupivacaine) on different occasions.
Clinical Assessment
History
- "Deep, aching, dull" pain.
- Worsened by looking up (hanging washing) or turning head (reverse parking).
- Morning stiffness common.
- History of MVA (Whiplash).
Examination
- Inspection: Normal alignment or mild torticollis.
- ROM: Restricted Extension and Rotation.
- Palpation: Paraspinal Tenderness over the facet line (2cm from midline). Deep pressure reproducing "the pain".
- Neurology: Must be NORMAL.
- Provocative Test: Extension + Rotation to the affected side ("Closing the door" on the facet).
Imaging and Investigations
Workup Protocol
X-RayScreening
- AP/Lat/Oblique.
- Look for: Joint space narrowing, sclerosis, osteophytes.
- "Shingle Sign": Visualizes facet alignment on lateral view.
CT ScanBone Detail
- More sensitive for OA.
- Rule out fracture or lysis.
- Note: OA presence does NOT confirm pain source.
Diagnostic BlockGold Standard
- Medial Branch Block (MBB).
- Injection of local anesthetic (Lignocaine/Bupivacaine) onto the nerve supply.
- Diagnostic Criteria: Greater than 80% pain relief for the duration of the anesthetic.
Management Algorithm
Clinical Algorithm
Facet Pain Management
Loading flowchart...
Surgical Technique
Radiofrequency Neurotomy (RFA)
- Indication: Positive response to TWO diagnostic blocks.
- Goal: Thermal coagulation of the medial branch nerve to interrupt pain signals.
- Mechanism: Heat (80-90°C) creates a lesion.
Technique:
- Placement: Electrode placed Parallel to the nerve (along the waist of the articular pillar).
- Why Parallel?: Electricity flows sideways. Placing the needle perpendicular ("Gun barrel") creates a smaller lesion and might miss the nerve.
- Testing:
- Sensory: 50Hz (Patient feels buzzing in neck).
- Motor: 2Hz (Look for multifidus twitch). Absence of arm twitch is critical (Rule out root stimulation).
- Lesioning: 90 seconds @ 80°C. Multiple lesions per nerve.
Outcomes:
- 60-80% of patients get relief.
- Duration: 9-12 months (nerve regenerates).
- Can be repeated.
Complications
| Complication | Risk | Note |
|---|---|---|
| Neuritis | Common (5%) | Burning pain (Sunburn feeling). Self-limiting (2-4 weeks). |
| Motor Nerve Injury | Rare | Drift of needle anteriorly hitting the Nerve Root. Avoid by Motor Testing. |
| Infection | Very Rare | Epidural abscess. |
| No Relief | 20-30% | Technical failure or Incorrect diagnosis (False pos block). |
Non-Operative Management
Physical Therapy
- Multimodal: Isometric strengthening, ROM, Scapular stabilization.
- Ergonomics: Workstation setup (monitor height).
- Psychology: CBT for chronic pain.
Medications
- NSAIDs.
- Neuropathic agents (Gabapentin/Pregabalin) - questionable efficacy for pure facet pain.
Postoperative Care
- Post-RFA:
- Ice packs for sore neck.
- Resume normal activity immediately.
- Physio to capitalize on the "Pain-free window".
Outcomes and Prognosis
- Natural History: Recurrent/Relapsing course.
- RFA Efficacy: The Lord 1996 NEJM RCT showed median relief of 263 days (vs 8 days for sham).
- Whiplash: Poorer prognosis if litigation ongoing, high baseline pain, or Catastrophizing.
Evidence Base
Evidence
Prevalence of Cervical Facet Pain after Whiplash
Lord, Barnsley, Wallis, Bogduk • Spine (Phila Pa 1976) (1996)
Key Findings:
- Placebo-controlled local anaesthetic blocks in 68 chronic post-whiplash neck-pain patients.
- Overall prevalence of cervical zygapophysial joint pain (C2/3 or below) was 60% (95% CI 46-73%).
- C2/3 joint pain prevalence was 50% in patients with dominant headache.
- Diagnosis survived placebo challenge, confirming it is a genuine clinical entity.
Clinical implication: Facet joints are the single most common identifiable source of chronic neck pain after whiplash.
Evidence
Prevalence by Comparative Blocks
Barnsley, Lord, Wallis, Bogduk • Spine (Phila Pa 1976) (1995)
Key Findings:
- Double-blind comparative blocks (lignocaine vs bupivacaine) in 50 chronic post-whiplash patients.
- Painful zygapophysial joints identified in 54% (95% CI 40-68%).
- Established the comparative-block paradigm prior to the later placebo-controlled study.
- Cervical facet pain was the most common source in this population.
Clinical implication: Independent confirmation that facet pain dominates chronic post-whiplash neck pain.
Evidence
Landmark RCT: Radiofrequency Neurotomy
Lord, Barnsley, Wallis, McDonald, Bogduk • N Engl J Med (1996)
Key Findings:
- 24 patients with block-confirmed facet pain randomised to active RFA (80 degrees C, multiple lesions) vs sham.
- Median time to return of 50% pain was 263 days (active) vs 8 days (sham), p=0.04.
- At 27 weeks 7/12 active patients were pain-free vs 1/12 sham.
- Numbness in the treated nerve territory occurred but was not troubling to patients.
Clinical implication: The pivotal trial establishing that RFA produces durable relief in correctly selected facet pain.
Evidence
Effectiveness in Practice
MacVicar, Borowczyk, MacVicar, Loughnan, Bogduk • Pain Med (2012)
Key Findings:
- 104 patients selected by controlled diagnostic blocks, treated by ISIS-trained operators.
- Successful outcome (complete or at least 80% relief, restored ADLs) in 61-74% across two practices.
- Median duration of relief allowing for repeat treatment was 20-26 months.
- Demonstrates real-world reproducibility when rigorous technique and selection are used.
Clinical implication: Outcomes depend on diagnostic rigour and operator technique, not the procedure alone.
Evidence
Third Occipital Nerve Headache
Lord, Barnsley, Wallis, Bogduk • J Neurol Neurosurg Psychiatry (1994)
Key Findings:
- C2/3 (third occipital nerve) headache prevalence was 27% across all whiplash patients.
- In patients with dominant headache the prevalence rose to 53%.
- No history or examination feature reliably predicted the diagnosis before nerve blocks.
- Tenderness over the C2/3 joint was significantly associated with a positive diagnosis.
Clinical implication: Cervicogenic headache from C2/3 is common after whiplash and requires TON blocks to diagnose.
Evidence
Radiofrequency Lesion Geometry
Cosman, Gonzalez • Pain Pract (2011)
Key Findings:
- Photographic temperature mapping shows RF lesions extend radially around the electrode tip, not beyond it.
- Lesion grows along the active tip, so electrodes laid parallel to the nerve capture a longer segment.
- A perpendicular tip risks the nerve slipping past the narrow lesion edge.
- Larger tips, higher tip temperature and longer lesion times enlarge the lesion.
Clinical implication: Lay the electrode parallel to the articular pillar so the lesion runs along the medial branch.
Evidence
False-Positive Rate of Single Blocks
Barnsley, Lord, Wallis, Bogduk • Clin J Pain (1993)
Key Findings:
- Single uncontrolled blocks compared against a double-blind comparative-block reference standard.
- False-positive rate of single blocks was 27% (16 of 60 joints; 95% CI 15-38%).
- Causes: placebo response, systemic absorption and spread to adjacent structures.
- Uncontrolled blocks have substantially reduced specificity.
Clinical implication: Never rely on a single block; confirm with a second (comparative or placebo-controlled) block.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
Viva scenarioStandard
Chronic Neck Pain
Clinical prompt
“45F, MVA 6 months ago. Chronic neck pain, worse looking up. MRI shows some degeneration C5/6. Physio failed. What is your approach?”
Practical approach
The history is suggestive of **Cervical Facet Arthropathy** (Axial pain + Extension + Trauma).
**Plan**:
1. **Explain**: MRI degeneration is common and may not be the cause. The diagnosis is clinical + interventional.
2. **Diagnosis**: Arrange **diagnostic Medial Branch Blocks**.
- Must be done under fluoroscopy.
- Need greater than 80% relief to call it positive.
- Ideally repeat (double block) to confirm.
3. **Treatment**: If blocks positive → **Radiofrequency Ablation**. If negative → reconsider Disc, Muscle, or central sensitization.
Key clinical points
Clinical triad (Axial, Extension, Trauma)
Role of MBB
Don't operate (Fusion) for axial pain alone
Common pitfalls
Offering fusion based on MRI
Skipping the diagnostic blocks
Further questions
“Describe the anatomy of the nerve you are blocking.”
Viva scenarioStandard
Cervicogenic Headache
Clinical prompt
“A patient complains of unilateral occipital headaches radiating from the neck. Worse with neck rotation. Which joint is culpable?”
Practical approach
This is classic for **C2/3 Facet Joint** pathology.
**Innervation**:
- Supplied by the **Third Occipital Nerve (TON)** (dorsal ramus C3).
- And the C2 medial branch.
**Testing**:
- TON block.
**Treatment**:
- Pulsed or Thermal RFA of the TON.
**Differential**: Tension headache, Migraine, Occipital Neuralgia.
Key clinical points
C2/3 referral pattern
Third Occipital Nerve
Headache differential
Common pitfalls
Confusing with C1/2 (Atlantoaxial) - which causes rotation loss but different pain
Missing Temporal Arteritis in elderly
Further questions
“Why is C1/2 pathology different to C2-C7?”
Viva scenarioStandard
Radiofrequency Neurotomy Technique
Clinical prompt
“You are performing cervical medial branch radiofrequency neurotomy. How do you position the electrode, why, and how do you confirm safe placement before lesioning?”
Practical approach
The aim is to coagulate the medial branch along its course on the waist of the articular pillar.
**Electrode position**:
- Place the active tip **parallel** to the nerve along the articular pillar, not perpendicular ('gun-barrel').
- The thermal lesion grows radially around and along the active tip, so a parallel tip captures a longer segment of nerve; a perpendicular tip risks the nerve escaping the narrow lesion edge.
**Confirmation before lesioning**:
- **Sensory stimulation at 50 Hz** - concordant buzzing in the neck at low voltage confirms proximity.
- **Motor stimulation at 2 Hz** - expect multifidus twitch; **absence of arm/forearm twitch** confirms you are not on the ventral ramus/nerve root.
**Lesion**: around 80-90 degrees C for roughly 90 seconds, with multiple lesions to account for anatomical variation. Each target joint needs two medial branches treated (same level and level above).
Key clinical points
Parallel placement maximises nerve captured in the lesion
Sensory 50 Hz and motor 2 Hz testing before lesioning
Absence of arm twitch excludes ventral ramus stimulation
Treat two medial branches per joint (dual innervation)
Common pitfalls
Perpendicular ('gun-barrel') placement missing the nerve
Lesioning without motor testing and injuring the nerve root
Treating only one medial branch and leaving the joint partially innervated
Further questions
“Why does relief from RFA last only 9-18 months and how do you counsel the patient about this?”
MCQ Practice Points
Diagnosis
Q: What is the false positive rate of a single uncontrolled medial branch block? A: About 27% (Barnsley 1993, 95% CI 15-38%). This is why dual blocks are required for definitive diagnosis.
Anatomy
Q: The C5/6 facet joint is innervated by which nerves? A: C5 and C6 medial branches. (Same level and level above).
Technique
Q: For maximum efficacy, how should the RFA electrode be placed relative to the nerve? A: Parallel. This maximizes the length of nerve captured in the thermal lesion.
History
Q: Which movement typically aggravates facet joint pain? A: Extension and Rotation. This mechanially loads the joint.
Complication
Q: What is the most common side effect of RFA? A: Post-neurotomy Neuritis (Sunburn sensation). Occurs in 5% of patients.
Guidelines, Registries & Global Practice
Global Epidemiology
- Neck pain is among the leading global causes of years lived with disability (Global Burden of Disease).
- After whiplash, cervical facet joints are the most common identifiable pain source (around 60% of chronic cases; C2/3 and C5/6 most frequent).
- Female predominance; recovery is strongly modulated by psychosocial factors and the local compensation environment.
| Body | Diagnostic Blocks | RFA Position |
|---|---|---|
| NICE (UK) | Not recommended as routine for non-specific neck pain | RFA not recommended outside research for axial neck pain |
| Spine Intervention Society / ASRA | Two controlled (comparative or placebo) blocks required | RFA endorsed in rigorously selected, block-positive patients |
| NASS (US) | Controlled blocks to confirm before ablation | RFA an option after positive controlled blocks |
| EFORT / European pain societies | Comparative blocks favoured; placebo control debated | RFA accepted for confirmed facet pain |
Practice Variation (high- vs limited-resource)
- High-resource settings: fluoroscopy- or CT-guided diagnostic blocks and RFA are routine in pain/spine services.
- Limited-resource settings: image-guided blocks and RFA equipment may be unavailable; care relies on physiotherapy, analgesia and activity modification, with surgical fusion reserved for instability or deformity.
- The major payer/policy divergence is whether controlled blocks are mandated before RFA (SIS/ASRA, NASS) or whether the whole pathway is restricted (NICE).
Controversies & Areas of Uncertainty
- Placebo vs comparative blocks: Comparative blocks (two anaesthetics) still carry residual false positives; only placebo-controlled triple blocks fully exclude placebo, but these are impractical in routine care.
- NICE vs interventionalist societies: NICE restricts diagnostic blocks and RFA for non-specific neck pain, citing weak trial evidence, whereas SIS/ASRA/NASS support RFA when strict block-based selection is applied. The conflict largely reflects how patients are selected.
- Imaging-pain mismatch: Degenerative facet changes on CT/MRI correlate poorly with the pain source, so imaging cannot confirm or exclude the diagnosis.
- Durability and repetition: Relief is finite because the medial branch regenerates; the optimal re-treatment interval and long-term effect on adjacent-segment health remain undefined.
- Whiplash chronicity: Cross-jurisdiction differences in chronicity highlight the contribution of psychosocial and compensation factors rather than a purely structural cause.
Exam Day Cheat Sheet
Exam day cheat sheet
Facet Summary
Key Concepts
- Axial Pain (No Radiculopathy)
- Extension Loading pattern
- MBB is gold standard diagnosis
- Double block required
Anatomy
- Dual Innervation (Same + Above)
- C2/3 = Headache (TON)
- C5/6 = Shoulder
- Facet angles 45 deg
Treatment
- Conservative first
- RFA (Parallel placement)
- Success = 9-12 months relief
- No Fusion
- Sensory + Motor Testing
Stats
- 60% of chronic post-whiplash neck pain
- 27% False-Positive Rate (Single Block)
- 54-55% in comparative-block series
- Female predominance
Image Manifest
- [1-preoperative-image-a-plain-radiograph-lateral-imag.png]: Lateral X-ray showing facet sclerosis
- [5-plain-radiographs-of-a-57-year-old-man-a-lateral-i.png]: Lateral spondylosis