====== Facet Joint Pathology ======

[[Facet joint]]s (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