Lumbar Puncture (Spinal Tap)
Lumbar puncture, also known as spinal tap, is an invasive procedure where a hollow
needle is inserted into the space surrounding the subarachnoid space in the lower back to obtain
samples of cerebrospinal fluid (CSF) for qualitative analysis. Most of the disorders of the
central nervous system are diagnosed in relation to the changes in the composition and dynamics of
the CSF.
A lumbar puncture may also be used to measure CSF, instill medications, or introduce a contrast
medium into the spinal canal. The procedure usually takes around 30 to 45 minutes and can be done
on an outpatient basis at a hospital or clinic.
Indication
Measure cerebrospinal fluid (CSF) pressure
Assist in the diagnosis of suspected CNS infections (bacterial or viral meningitis,
meningoencephalitis), intracranial or subarachnoid hemorrhage, and some malignant
disorders
Evaluate and diagnose demyelinating or inflammatory CNS processes such as Multiple
Sclerosis, Guillan-Barré Syndrome (GBS), Acute Disseminated Encephalomyelitis (ADEM)
Infuse medications which include spinal anesthesia before surgery, contrast material for
diagnostic imaging such as CT-myelography, and chemotherapy drugs directly into the
spinal canal
Treat normal pressure hydrocephalus, cerebrospinal fistulas, and idiopathic
intracranial hypertension (IIH).
Placement of a lumbar CSF drainage catheter
, Contraindication
Increased intracranial pressure due to a brain tumor. Cerebral or cerebellar herniation
with severe neurological deterioration may occur after the withdrawal of CSF fluid.
Skin infection near the puncture site. The presence of skin infection near the site of the
lumbar puncture increases the risk of contamination of infected material into the CSF.
Severe degenerative vertebral joint disease. There will be difficulty in passing the needle
through the degenerated arthritic interspinal space.
Severe coagulopathy. Due to the significant risk of epidural hematoma formation.
Equipment
The lumbar puncture kit contains:
Sterile gloves
Sterile drapes and procedure tray
Sterile gauze pads
Aseptic solution: povidone-iodine solution (Betadine)
Local anesthetic: Lidocaine 1% solution
25G needle
10ml syringe (1)
Spinal needle with stylet (size 22G or 25G)
CSF tube (2 to 4)
Stopcock
Manometer tubing
Procedure
The step-by-step procedure for a lumbar puncture (spinal tap) is as follows:
1. Position the patient in a fetal position.
The patient is positioned on his side at the edge of the bed with his knees drawn up to his
abdomen and chin tucked against his chest (fetal position) or sitting while leaning over a
bedside table. When the patient is positioned supine, pillows are provided to support the
spine on a horizontal plane.
2. Sterilize the site of insertion.
The skin site is prepared and draped, and a local anesthetic is injected.
3. Insert the spinal needle.
The spinal needle is inserted in the midline between the spinous processes of the vertebrae
(usually between the third fourth or fourth and fifth lumbar vertebrae).
Lumbar puncture, also known as spinal tap, is an invasive procedure where a hollow
needle is inserted into the space surrounding the subarachnoid space in the lower back to obtain
samples of cerebrospinal fluid (CSF) for qualitative analysis. Most of the disorders of the
central nervous system are diagnosed in relation to the changes in the composition and dynamics of
the CSF.
A lumbar puncture may also be used to measure CSF, instill medications, or introduce a contrast
medium into the spinal canal. The procedure usually takes around 30 to 45 minutes and can be done
on an outpatient basis at a hospital or clinic.
Indication
Measure cerebrospinal fluid (CSF) pressure
Assist in the diagnosis of suspected CNS infections (bacterial or viral meningitis,
meningoencephalitis), intracranial or subarachnoid hemorrhage, and some malignant
disorders
Evaluate and diagnose demyelinating or inflammatory CNS processes such as Multiple
Sclerosis, Guillan-Barré Syndrome (GBS), Acute Disseminated Encephalomyelitis (ADEM)
Infuse medications which include spinal anesthesia before surgery, contrast material for
diagnostic imaging such as CT-myelography, and chemotherapy drugs directly into the
spinal canal
Treat normal pressure hydrocephalus, cerebrospinal fistulas, and idiopathic
intracranial hypertension (IIH).
Placement of a lumbar CSF drainage catheter
, Contraindication
Increased intracranial pressure due to a brain tumor. Cerebral or cerebellar herniation
with severe neurological deterioration may occur after the withdrawal of CSF fluid.
Skin infection near the puncture site. The presence of skin infection near the site of the
lumbar puncture increases the risk of contamination of infected material into the CSF.
Severe degenerative vertebral joint disease. There will be difficulty in passing the needle
through the degenerated arthritic interspinal space.
Severe coagulopathy. Due to the significant risk of epidural hematoma formation.
Equipment
The lumbar puncture kit contains:
Sterile gloves
Sterile drapes and procedure tray
Sterile gauze pads
Aseptic solution: povidone-iodine solution (Betadine)
Local anesthetic: Lidocaine 1% solution
25G needle
10ml syringe (1)
Spinal needle with stylet (size 22G or 25G)
CSF tube (2 to 4)
Stopcock
Manometer tubing
Procedure
The step-by-step procedure for a lumbar puncture (spinal tap) is as follows:
1. Position the patient in a fetal position.
The patient is positioned on his side at the edge of the bed with his knees drawn up to his
abdomen and chin tucked against his chest (fetal position) or sitting while leaning over a
bedside table. When the patient is positioned supine, pillows are provided to support the
spine on a horizontal plane.
2. Sterilize the site of insertion.
The skin site is prepared and draped, and a local anesthetic is injected.
3. Insert the spinal needle.
The spinal needle is inserted in the midline between the spinous processes of the vertebrae
(usually between the third fourth or fourth and fifth lumbar vertebrae).
