Cervical Facet Arthropathy

Cervical facet arthropathy is pain arising from the cervical zygapophysial (facet) joints. It is typically axial and non-radicular, and the diagnosis is made by the response to controlled medial branch blocks, not by imaging.

Who and where. After whiplash, the facet joints are the most common identifiable source of chronic neck pain, around 60% of cases (Lord 1996). C2/3 and C5/6 are the levels most frequently involved. There is a female predominance, and onset is 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. A structured, block-based pathway is therefore essential before committing a patient to ablation.

The joint. The facet is a synovial joint, oriented at 45 degrees in the coronal plane, and it resists anterior translation and rotation.

Innervation. This is the anatomy radiofrequency ablation depends on. Each joint is supplied by the medial branch of the dorsal ramus, and each has dual innervation, from the same level and the level above: the C4/5 joint is supplied by the C4 and C5 medial branches. The exception is C2/3, supplied by the third occipital nerve (TON) and the C2 medial branch.

Referral patterns (Bogduk maps). The referral zones do not follow dermatomes. Each joint has its own:

• C2/3: occiput and mastoid (headache)
• C3/4: upper neck
• C5/6: lower neck, trapezius ridge and acromion
• C6/7: scapular border

Classification relies on the response to diagnostic blocks, not on imaging. Radiographic grading describes the arthritis, which often correlates poorly with the pain.

The grading examiners expect for whiplash is the Quebec Task Force classification of Whiplash-Associated Disorders (Spitzer et al, 1995). It is worth stating explicitly because it drives triage and prognosis.

Headache, dizziness, tinnitus, dysphagia, temporomandibular pain and memory disturbance may accompany any grade and are not themselves graded.

Where facet pain fits. The vast majority of presentations are Grade I to II. Grade IV (fracture or dislocation) mandates immobilisation and the cervical-fracture pathway, not a pain-block pathway.

History. The pain is deep, aching and dull, and there is often a history of a motor-vehicle accident (whiplash). It is worse looking up, as when hanging washing, or turning the head, as when reverse parking, and morning stiffness is common.

Examination. Alignment is normal or there is a mild torticollis, and extension and rotation are restricted. There is paraspinal tenderness over the facet line, 2cm from the midline, where deep pressure reproduces "the pain". The provocative test is extension with rotation to the affected side, which loads the facet: "closing the door" on it.

Neurology must be normal. If arm pain exceeds neck pain, or there is a neurological deficit, the nerve root is the suspect, not the facet. The table sets facet pain against discogenic pain and radiculopathy.

Physical therapy is multimodal: isometric strengthening, range of motion and scapular stabilisation. It is combined with ergonomic attention to the workstation (monitor height) and with CBT for chronic pain.

Medication. NSAIDs are used. Neuropathic agents such as gabapentin and pregabalin are of questionable efficacy for pure facet pain.

Intra-articular corticosteroid. This is the request that most often arrives from primary care, and the honest answer is that intra-articular steroid is not part of the evidence-based pathway for cervical facet pain, which is why it is absent from the management algorithm. Barnsley and colleagues randomised 41 patients with blocks-confirmed cervical zygapophysial joint pain after whiplash to intra-articular betamethasone 5.7 mg or bupivacaine 0.5% under double-blind conditions. The median time to return of half the pre-injection pain was 3 days with steroid against 3.5 days with local anaesthetic (p = 0.42). Fewer than half of all patients had relief beyond one week and fewer than one in five beyond a month, whichever they received (N Engl J Med 1994; PMID 8127332).

Distinguish the three needles, because they are constantly conflated.

• A medial branch block is diagnostic and anaesthetic only.
• Radiofrequency neurotomy is the therapeutic procedure, and treats the same nerves the block anaesthetised.
• Intra-articular steroid targets the joint itself, and has neither diagnostic value (the injectate spreads unpredictably) nor demonstrated durable benefit.

The practical consequence. A patient who responds to a properly controlled medial branch block should be offered neurotomy, not a course of joint injections. And a patient who has had unhelpful intra-articular injections has not been shown to lack facet-mediated pain.

The pathway runs from six weeks of conservative care to two diagnostic blocks to ablation. Neurological signs take the patient off it at the start, and a block that leaves the pain unchanged sends the search elsewhere.

Conventional thermal RF and pulsed RF are two distinct modalities, and the distinction is examinable.

Thermal RF destroys the medial branch by heat coagulation; it is the modality validated by the Lord NEJM trial and the basis of the durable relief quoted under outcomes. Pulsed RF exposes the nerve to a rapidly fluctuating electric field while keeping the tissue cool, so it does not coagulate the nerve. It is proposed where a destructive lesion is undesirable.

The third occipital nerve. TON neurotomy is technically harder, as the nerve over the C2/3 joint is larger and more variable. Thermal lesioning there predictably causes temporary cutaneous numbness and transient unsteadiness or ataxia in the treated territory. That side-effect profile is part of why pulsed RF is sometimes considered there, though thermal neurotomy remains the better-evidenced option.

Natural history. The course is recurrent and relapsing.

After neurotomy. Between 60 and 80% of patients get relief. It is durable but not permanent, because the medial branch regenerates, and the quoted duration varies: 9-12 months; a median of 263 days against 8 days for sham in the Lord 1996 NEJM RCT; and 17-20 months in rigorous practice series.

Whiplash. The prognosis is poorer if litigation is ongoing, if baseline pain is high, or if the patient is catastrophising.

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.

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).

• 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.