Lumbar Puncture (Fluoroscopy-Guided)

Indications

• CSF sampling (suspected meningitis, subarachnoid hemorrhage, MS, malignancy)
• Measurement of opening pressure (e.g., idiopathic intracranial hypertension)
• Therapeutic CSF removal
• Intrathecal medication / contrast administration
• Failed bedside LP (obesity, degenerative spine, prior surgery)

Patient prep

• Review coagulation; hold anticoagulants/antiplatelets per guidelines
• Exclude raised ICP / posterior fossa mass when clinically indicated (imaging first if focal deficit, papilledema, or altered consciousness)
• Sterile prep; consent
• No skin infection over puncture site

Contrast

Technique

• Position prone (or lateral decubitus if opening pressure needed) on fluoro table
• Sterile prep and drape; local anesthetic
• Fluoroscopically target an interspace below the conus (commonly L3-L4 or L2-L3)
• Advance spinal needle under intermittent fluoroscopy to the thecal sac
• Confirm CSF return; measure opening pressure (lateral decubitus) if indicated; collect samples
• A small amount of intrathecal contrast may be used to confirm position in difficult cases (use intrathecal-approved agent only)

Series / Sequences

Key points

• No contrast needed for routine diagnostic LP; if contrast is used to confirm position, only intrathecal-approved nonionic agent
• Image brain first if signs of raised ICP or focal neurologic deficit (herniation risk)
• Lateral decubitus position required for accurate opening pressure
• Smaller-gauge atraumatic (pencil-point) needles reduce post-dural-puncture headache
• Fluoro guidance valuable in obesity, scoliosis, degenerative disease, or after spinal surgery

References