Lumbar Puncture with Contrast at L3-L4: Procedure Overview

The procedure described—injection of contrast dye into the subarachnoid space at the L3-L4 vertebral level—is a lumbar puncture (spinal tap) with contrast, typically performed for:

• Myelography: CT myelogram to visualize spinal cord, nerve roots, and canal pathology (stenosis, herniation, tumor) when MRI is contraindicated.
• Cisternography: Evaluate CSF flow (e.g., suspected CSF leak, hydrocephalus).
• Intrathecal Chemotherapy/Anesthesia: Drug delivery (contrast confirms placement).

Key Points

• Landmark: L3-L4 or L4-L5 interspace (below spinal cord terminus at L1-L2).
• Needle: Quincke (cutting) or Sprotte (atraumatic) spinal needle.
• Contrast: Iodinated, water-soluble, non-ionic (e.g., iohexol, iopamidol).
• Post-Procedure: Bed rest 2–4 hrs, hydration, monitor for post-dural puncture headache (PDPH).
• Risks: PDPH, infection, bleeding, nerve root injury, seizure (rare, if contrast enters brain).

Performed by radiologists, neurologists, or anesthesiologists under fluoroscopic or CT guidance.