A lumbar puncture, or spinal tap, is a procedure where cerebrospinal fluid is collected from the lower back for diagnostic purposes. It is indicated for conditions like meningitis, subarachnoid hemorrhage, and certain CNS diseases. Contraindications include infected skin at the needle site, brain abnormalities, or increased intracranial pressure. The procedure involves locating the interspace between vertebrae, inserting a needle at a slight upward angle, and checking for fluid return. Potential complications are local pain, infection, bleeding, spinal fluid leak, or spinal headache.
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Lumbar puncture
2. • A lumbar puncture (or LP, and
colloquially known as a spinal tap) is
a diagnostic procedure that is
performed in order to collect a
sample of cerebrospinal fluid (CSF)
3. INDICATIONS
Lumbar puncture should be performed for the
following indications:
• Suspicion of meningitis
• Suspicion of subarachnoid hemorrhage (SAH)
• Suspicion of central nervous system (CNS)
diseases such as Guillain-Barré syndrome and
carcinomatous meningitis
• Therapeutic relief of pseudotumor cerebri
4. CONTRAINDICATIONS
Absolute contraindications for lumbar puncture are
• presence of infected skin over the needle entry site and the
presence of unequal pressures between the supratentorial and
infratentorial compartments.
• Midline shift
• Loss of suprachiasmatic and basilar cisterns
• Posterior fossa mass Loss of the superior cerebellar cistern
• Loss of the quadrigeminal plate cistern
Relative contraindications for lumbar puncture include the following:
Increased intracranial pressure (ICP)
Coagulopathy
Brain abscess
5. PROCEDURE
• After suitable local
anesthesia
• Position child in either
sitting or lateral
recumbent position
with hips,knees and
neck flexed.
6. • Wearing nonsterile
gloves, locate the L3-L4
interspace by palpating
the right and left
posterior superior iliac
crests and moving the
fingers medially toward
the spine
• Palpate that interspace
(L3-L4), the interspace
above (L2-L3), and the
interspace below (L4-L5)
to find the widest space.
8. • Insert the needle at a slightly
cephalad angle, directing it
toward the umbilicus. Advance
the needle slowly but smoothly.
Occasionally, a characteristic
“pop” is felt when the needle
penetrates the dura. Otherwise,
the stylet should be withdrawn
after approximately 4-5 cm and
observed for fluid return. If no
fluid is returned, replace the
stylet, advance or withdraw the
needle a few millimeters, and
recheck for fluid return. Continue
this process until fluid is
successfully returned
9. • For measurement of the
opening pressure, the
patient must be in the
lateral recumbent position.
After fluid is returned from
the needle, attach the
manometer through the
stopcock, and note the
height of the fluid column.
The patient’s legs should be
straightened during the
measurement of the open
pressure, or a falsely
elevated pressure will be
obtained
10. • If the CSF flow is too
slow, ask the patient to
cough or bear down (as in
the Valsalva maneuver),
or ask an assistant to
press intermittently on
the patient’s abdomen to
increase the flow.
Alternatively, the needle
can be rotated 90° so that
the bevel faces cephalad.
11. • Replace the stylet, and
remove the needle (see
the video below). Clean
off the skin preparation
solution. Apply a sterile
dressing, and place the
patient in the supine
position.
12. COMPLICATIONS
• Local pain
• Infection
• Bleeding
• Spinal Fluid Leak
• Hematoma
• Spinal Headache/Post-tap headache
• Acquired epidermal spinal cord tumor (caused by
implantation of epidermal material into spinal
canal if no stylet is used on skin entry)