Medial Branch Block, Lumbar Spine

KEY FACTS

Terminology

• Selective anesthesia of lumbar nerve medial branch in diagnostic evaluation of lumbar facet joint pain

Preprocedure

• Facet joint pain

  • Useful in selecting patients for medial branch radiofrequency ablation procedure

Procedure

• Target: Junction of superior articular process and transverse process

  • Medial branch is numbered along with exiting lumbar nerve root

  • L5 medial branch innervates inferior L4/5 and superior L5/S1 facet joint

• Patient positioning

  • Prone: Angulate C-arm such that “eye” of “Scotty dog” is well visualized

Post Procedure

• Expectation

  • Significant reduction in facet joint pain

  • < 100% pain relief decreases likelihood of successful rhizotomy

    • –

      Injection of superior and inferior rami essential to effectively block nervous supply to facet joint

Outcomes

• Failure of pain relief

  • Incorrect level or poor needle placement

  • Facet joint may not be source of pain

• Complications

  • Intravascular injection: Spinal cord ischemia

  • Dural puncture: Cauda equina injury, meningitis

TERMINOLOGY