Facet Joint Pathology
Facet joints (zygapophyseal joints) are paired synovial joints located between the articular processes of adjacent vertebrae. They are critical for spinal stability and motion but are also a common source of axial pain.
Types of Facet Joint Pathology
- Facet Joint Arthropathy (Degenerative)
- Most common type
- Features: cartilage loss, osteophyte formation, joint space narrowing, subchondral sclerosis
- Facet Joint Syndrome
- Clinical diagnosis of pain originating from facet joints
- Confirmed by medial branch blocks or intra-articular injections
- Facet Joint Effusion
- Fluid in the joint seen on MRI
- Often associated with acute pain
- Facet Cyst
- Synovial cysts from degenerated joints
- May cause radiculopathy or spinal stenosis
- Facet Joint Hypertrophy
- Bone overgrowth contributing to foraminal or central stenosis
- Facet Fracture or Dislocation
- Usually post-traumatic
- Can result in instability or neurologic compromise
Diagnostic Tools
| Modality | Role |
|---|---|
| MRI | Detects joint effusion, inflammation, adjacent edema |
| CT | Superior for bony changes: sclerosis, osteophytes |
| SPECT/CT | Detects increased metabolic activity; identifies active pain generators |
| Medial Branch Block | Diagnostic and therapeutic; confirms facetogenic pain |
Imaging Clues (MRI)
- T2 hyperintensity within joint (effusion)
- Joint irregularity, narrowing
- Edema in adjacent bone
Treatment Options
- Conservative
- NSAIDs
- Physical therapy
- Postural training
- Interventional
- Intra-articular steroid injections
- Medial branch nerve blocks
- Radiofrequency ablation (RFA) of medial branches
- Surgical
- Indicated in instability or refractory pain
- Options: joint resection, spinal fusion
Clinical Notes
- Pain is typically axial, worsened by extension/rotation
- Often no clear correlation with MRI alone
- SPECT/CT may reveal metabolically active joints not seen on MRI