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  • • Central nervous system (CNS) infection (viral, fungal, or bacterial) or malignancy.

    • Intracranial pressure or pseudotumor.

    • Metabolic studies.

    • Aminoacidopathies.

    • Neurotransmitter disorders.

    • • Undiagnosed movement disorders.

      • Undiagnosed infantile or pediatric epilepsy.

    • Demyelinating disease (eg, multiple sclerosis).


  • • CNS herniation.

    • Unilateral mass lesion with edema or mass effect.


  • • Suspected focal mass lesion.

  • • Spinal needle: 0.5 inch for neonate, 22 gauge.

    • Manometer.

    • Sterile collection tubes (sufficient number for studies).

    • 3-way stopcock.

    • Flexible tubing.

  • • Herniation (extremely rare) is associated with focal structural lesions causing increased intracranial pressure.

    • Infection (extremely rare).

    • Headache (rare).

    • Back pain.

  • • Placing the patient with the sacral plane vertical is key.

    • The head of the patient should be on your nondominant side. (Left-handed physicians should place the patient in the left lateral decubitus position.)

    • Use your nondominant thumb to palpate the spinous process of L4 and put your index finger on the iliac crest.

    • Use your dominant hand to manipulate the needle.

    • If positioning is felt to be correct, try rotating the needle 90 degrees.

    • If cerebrospinal fluid (CSF) flows slowly, be patient.

  • • Sterile technique.

    • Povidone-iodine preparation.

    • Sterile drape with fenestration over midlumbar spine.

    • Sedation, if needed.

    • Connect 3-way stopcock to flexible tubing and manometer at 90 degrees from each other.

    • Free end of tubing will connect to hub of needle.

  • • Lateral decubitus position.

    • Back arched in extreme lordosis.

    • Spine should be as perfectly horizontal as possible.

    • Sacral plane should be as vertical as possible (Figure 34–1).

Figure 34–1.

Lateral decubitus position.

  • • Spinous process of L4 is on line drawn between iliac crests.

    • Cauda equina is in midlumbar region.

    • Spinous processes are angled inferiorly (caudally).

  • • Palpate for L4 spinous process using iliac crests as landmarks (Figure 34–2).

  • • Place lumbar puncture needle between interspaces L4–5.

    • Angle the needle tip approximately 15–30 degrees from perpendicular to plane of back in rostral direction, aiming toward umbilicus (Figure 34–3).

  • • Needle remains fixed in horizontal plane to back.

    • Advance needle slowly until light resistance (a pop) is felt.

    • Remove stylet and check for CSF flow.

    • If no CSF flows, continue to advance the needle slowly.

    • If CSF flows, connect flexible tubing to hub of lumbar puncture needle.

    • Allow CSF to flow through tubing into manometer.

    • Hold base of manometer and stopcock at level of heart.

    • Straighten the patient’s back and legs.

    • When CSF stops advancing along manometer, measure opening pressure at meniscus.

    • Collect CSF for studies.

    • Measure closing pressure, if ...

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