Lumbar puncture

Lore & Background

Lumbar puncture is typically performed under local anesthesia using a sterile technique. A hypodermic needle is used to access the subarachnoid space and collect fluid. Fluid may be sent for biochemical, microbiological, and cytological analysis. Using ultrasound to landmark may increase success. The procedure is regarded as safe, but post-dural-puncture headache is a common side effect if a small atraumatic needle is not used. Increased intracranial pressure is a contraindication due to risk of brain matter being compressed and pushed toward the spine. Sometimes, lumbar punctures cannot be performed safely, for example due to a severe bleeding tendency.

Reader's Guide

Lumbar puncture is a key diagnostic tool for central nervous system diseases, particularly meningitis, subarachnoid hemorrhage, and other conditions. It also has therapeutic uses, such as injecting medications intrathecally for spinal anesthesia or chemotherapy, and in temporary treatment of idiopathic intracranial hypertension. The procedure's contraindications include idiopathic increased intracranial pressure, bleeding diathesis, and skin infection at the puncture site. Post-dural-puncture headache is the most common complication, but risk is reduced with atraumatic needles. Serious complications are extremely rare. The technique involves inserting a needle between lumbar vertebrae, typically at L3/L4 or L4/L5, to access the lumbar cistern below the spinal cord's termination.

Did You Know?

• Post-dural-puncture headache is a common side effect if a small atraumatic needle is not used.
• Increased intracranial pressure is a contraindication due to risk of brain matter being compressed and pushed toward the spine.
• The procedure may be used to detect whether someone has Stage 1 or Stage 2 Trypanosoma brucei.