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Lumbar Puncture

A lumbar puncture (also known as a spinal tap) is a medical procedure in which a needle is inserted into the lower back to remove a sample of cerebrospinal fluid (CSF) that surrounds the brain and spinal cord. 

The length of time a lumbar puncture takes around 30 minutes to an hour.

Most people experience some discomfort during a lumbar puncture, but the procedure is typically well-tolerated. Local anesthesia is used to numb the area where the needle is inserted, but some people may still feel some pressure or mild discomfort during the procedure.

Common diagnoses made by a lumbar puncture include:

  1. Meningitis, which is an inflammation of the membranes surrounding the brain and spinal cord.

  2. Encephalitis, which is an inflammation of the brain.

  3. Multiple sclerosis, which is a disease that affects the nervous system.

  4. Guillain-Barre syndrome, which is a disorder that affects the nerves outside of the brain and spinal cord.

  5. Intracranial hemorrhage, which is bleeding inside the skull.


A lumbar puncture can also be used to measure the pressure of the CSF, diagnose certain cancers, and deliver medications directly into the spinal canal.

Contraindications to Lumbar Puncture

● Possible raised intracranial pressure (ICP) with risk for cerebral herniation due to obstructive hydrocephalus, cerebral edema, or space-occupying lesion

● Thrombocytopenia (Low platelets, less than 60 generally) or other bleeding disorders, including taking blood thinners

● Suspected spinal epidural abscess


LP is a relatively safe procedure, but minor and major complications can occur even when standard infection control measures and good technique are used. These complications include:

● Post-LP headache

● Infection

● Bleeding

● Cerebral herniation

● Minor neurologic symptoms such as radicular pain or numbness

● Late onset of epidermoid tumors of the thecal sac

● Back pain

Stopping of Blood Thinners is ALWAYS guided by your doctor. Here are the general rules for non-urgent LPs.

●Unfractionated intravenous heparin drips – Two to four hours.

●Low-molecular-weight heparin – 12 to 24 hours.

Warfarin – Five to seven days.

●Newer oral anticoagulants (NOACs), apixabanedoxaban, and rivaroxaban – 72 hours. Dabigatran should be held 48 to 96 hours based on renal function.

●Subcutaneous heparin – <10,000 units per day is not believed to pose a substantial risk for bleeding.

Lumbar Puncture Procedure – What to Expect Stanford EdTech

See example Pre and Post LP instructions

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