Chapter 34. Lumbar Puncture

• • 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).

Absolute

• • CNS herniation.

  • Unilateral mass lesion with edema or mass effect.

Relative

• • 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).

• • 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 ...