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Ultrasound guidance during a lumbar puncture allows surgeons to more accurately identify landmarks. Learn what happens during the procedure
Ultrasound guidance during a lumbar puncture helps reduce the risk of injury, allowing surgeons to identify landmarks with greater accuracy. Learn about what happens during an ultrasound guided lumbar puncture.
What is a lumbar puncture?
A lumbar puncture procedure (also called a spinal tap) involves the insertion of a thin hollow needle (called a lumbar puncture needle) into the space around the spinal cord (subarachnoid space) in the lower back.
The cerebrospinal fluid (CSF) is a clear, watery substance around the brain and spinal cord (central nervous system or CNS). The fluid is responsible for various functions, such as protecting the CNS against shock, maintaining optimum pressure in the CNS, providing nutrients to the brain and spinal cord, and removing waste products.
Lumbar punctures may be done to diagnose diseases or treat them. Your doctor may perform a lumbar puncture to:
- Collect a small amount of CSF for lab analysis to diagnose diseases, such as meningitis, multiple sclerosis, cancer, or bleeding around the brain
- Measure CSF pressure in the spinal canal
- Reduce the pressure in the spinal canal by removing some CSF
- Inject medications or dyes for treatment or diagnostic purposes
An ultrasound guided lumbar puncture generally takes 45 minutes to complete. You may be allowed to go home the same day, although you may need someone to drive you home after the procedure. The procedure is generally done under moderate sedation, although some patients may need general anesthesia.
What happens before a lumbar puncture?
Before an ultrasound guided lumbar puncture, your doctor may:
- Take your medical history including history of allergies and chronic health conditions
- Order blood tests and CT scans to rule out hydrocephalus (excessive collection of fluid in and around the brain)
- Ask you not to eat or drink anything after midnight before your procedure
- Ask you about any medications you are taking (including nonsteroidal anti-inflammatory drugs and blood thinners)
- Tell you which medications you may take in the morning before the procedure and which you need to avoid
- Address any questions or concerns you may have regarding the procedure
What happens during a lumbar puncture?
- You may be administered a sedative to make you more comfortable during the procedure.
- You will lie face-down on the procedure table.
- The medical team may connect you to monitors to check your vitals, electrocardiogram, and oxygen saturation.
- Your doctor will clean the area with antiseptic solutions and apply surgical drapes.
- A local anesthetic will be injected at the site where the lumbar puncture needle will be inserted.
- Your doctor will use the ultrasound probe to look for the space between your lumbar vertebrae and insert the lumbar puncture needle through your skin into the spinal canal.
- You may be asked to change your position slightly once the needle is in the subarachnoid space (space around the spinal cord that contains cerebrospinal fluid or CSF).
- Your doctor may remove a small amount of CSF or inject medication depending on the reason for the lumbar puncture.
- The needle is withdrawn and pressure may be applied to the area to prevent bleeding.
- A bandage is applied (stitches are not needed).
- The intravenous line is removed.
- You may be asked to lie on your back or side for a few hours after the procedure.
What are the risks of a lumbar puncture?
Lumbar puncture is typically a safe procedure. Some of the side effects that may occur include:
- Bleeding
- Infection of the brain and its covering (meningoencephalitis)
- Headache
- Dizziness
- Backache
- Brainstem herniation or compression
