Indications

• Primarily performed in IR due to failed attempts without imaging.
• Diagnosis of meningitis.
• Diagnosis and/or therapeutic relief of idiopathic intracranial hypertension.
•  Administration of intrathecal chemotherapy.

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Contraindication

• Severe bleeding diathesis.
• Local infection, including epidural abscess.
• Intracranial mass lesions causing increased intracranial pressure.
  • Perform imaging to rule out mass lesions such tumor or abscesses.
• Trauma to the spinal cord or vertebrae​

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Pre-Procedure

Consent - Risks Include:

• Infection, bleeding, nerve damage (including nerve roots and spinal cord), CSF leak, inadquate specimen, headaches, cerebral herniation.

Imaging

• If increased intracranial pressure, to rule out mass lesion
• If concern for low conus with spinal dysraphism
  

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Labs

• None required, unless suspicion of bleeding disorder or at increased risk of hemorrhage.

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Technique

• Time-out
• Sterile technique​
• Positioning: Left lateral decubitus position, avoid extension of lumbar spine. In infants, this also requires holding in a curled position.
• Needle: 22G, 3.5 inch needle in most children, use 20/21G 6 inch needle in obese patient, 25G 1 or 3.5 inch needle in infants.
• Level of Entry: L3-4,  L4-5 or L5-S1. If procedure is being performed in infants, use ultrasound to determine level of the conus.
• Mark location and administer  local anesthetic (lidocaine 1% without epinephrine).
• Fluoroscopy: Advance spinal needle gradually using intermittent AP and lateral planes.
• Ultrasound (infants < 6 mo.): Hockey stick probe, direct visualization in longitudinal plain, aim for thecal sac with appreciable CSF. Angle needle between spinous processes and remain 1-2 vertebral levels below the level of conus.

• Aim between the spinous process with cephalad angulation.
• If needle deflects from soft tissue or bone, withdraw partially and re-insert.
• In older patients, may feel a give or "pop" when penetrating dura.
• Confirm CSF return by withdrawing stylet.
• Measure CSF pressure using the manometer, with base at the same height as the needle. Use extension in patient with IIH.​
• CSF collection: Divide into 4-5 tubes, 2-3 ml each. In infants, 1 ml each in 2-3 bottles should suffice. In IIH 15- 20 ml of CSF can be removed.
• Replace stylet before removing needle.
• Apply sterile dressing.

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Complications

• Post-procedure headache – affects approximately 1/3 of patients.
  • Bedrest may help. Remain supine immediately post-procedure.
• CSF leak - in rare instances, this may require a blood patch.
• Infection
• Bleeding
• Nerve injury, neurological symptoms are usually temporary
• Seizure
• Cerebral herniation (rare)​

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Post-Procedure

• Older patients should remain supine, particularly in patients with IIH (usually 1 hour).
• If postural headaches, remain supine until resolved.
  
• Avoid strenuous activity for 24 hours.
• Observe in PACU until 

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Considerations

Intrathecal administration of chemotherapy

• Perform LP as per above. Confirm the amount of CSF to be removed with oncologist. Replace stylet, but do not remove needle.
• The neurooncologist will then administer the chemotherapy  agent. Confirm who will remove needle and place dressing.

Infants

• If recent multiple unsuccessful attempts, then request ultrasound to look for evidence of hematoma.
• If significant hematoma and inadequate CSF, defer LP for 1-2 days.

Idiopathic Intracranial Hypotension

• ​Normal opening pressures range 11 - 28 cm H2O
• Opening pressures > 28 cm H2O are diagnostic of intracranial hypertension in children
• Remove 15 – 20 ml of CSF, to bring closing pressure within normal range and should lower than 15 cm of H2O

References

1. Pierce DB, Shivaram G, Koo KSH, Shaw DWW, Meyer KF, Monroe EJ. Ultrasound-guided lumbar puncture in pediatric patients: technical success and safety. Pediatr Radiol. 2018;48(6):875-881.
2. Avery RA. Reference range of cerebrospinal fluid opening pressure in children: historical overview and current data. Neuropediatrics. 2014;45(4):206-211.