What are the steps for a Lumbar Puncture (LP) procedure?

Lumbar Puncture Procedure Steps

The safest and most effective lumbar puncture procedure involves using an atraumatic narrow-bore needle in the lateral recumbent position, with passive CSF withdrawal, and limiting attempts to no more than four. 1

Preparation and Positioning

• Evaluate potential contraindications including space-occupying lesions with mass effects, coagulopathies (INR >1.5 or platelet count <40 × 10⁹/L), congenital spine abnormalities, and skin infections at the puncture site 2
• Identify patient-related risk factors such as younger age, female sex, history of headache, and BMI ≤25 kg/m² 2
• Communicate effectively with the patient to alleviate fears and concerns, as fear of the procedure increases risk of non-specific headache 2
• Position the patient in the lateral recumbent (supine) position, which is associated with lower risk of post-LP headache compared to sitting 1

Needle Selection

• Use an atraumatic narrow-bore needle (≥24 gauge) which significantly reduces post-LP headache risk (4.2% vs 11.0% with conventional cutting-bevel needles) 1
• Standard-length needles (70-90 mm) are appropriate for most adults, while longer needles (>90 mm) may be needed for obese patients 1
• Small-bore needles (≥24 gauge) are associated with lower rates of headache, back pain, and reduced risk of blood contamination 1

Procedure Steps

1. Identify the appropriate interspace (typically L3-L4 or L4-L5) using anatomical landmarks 2
2. Prepare and drape the area using sterile technique 2
3. Administer local anesthetic to the skin and deeper tissues 2
4. Insert the needle with the bevel oriented in a transverse plane (perpendicular to the longitudinal axis) 3
5. Advance the needle slowly until CSF flow is obtained 1
6. Allow passive (gravity) flow removal of CSF rather than active withdrawal with a syringe 1
7. Collect appropriate amount of CSF (up to 30 mL is considered safe) 1
8. Replace the stylet before withdrawing the needle 3
9. Apply sterile dressing to the puncture site 2

Post-Procedure Management

• Evidence shows that prolonged bed rest after LP is not associated with lower incidence of adverse events compared to immediate mobilization 1, 3
• Maintain adequate hydration with oral fluids 1
• Monitor for post-LP headache, which typically develops within 3 days and manifests as an orthostatic headache (worse when upright, better when lying flat) 2
• For post-LP headache, regular multimodal analgesia including acetaminophen and NSAIDs should be offered unless contraindicated 1

Important Considerations to Minimize Complications

• Avoid multiple attempts at dural puncture (risk approximately doubles with 2-4 attempts and increases five-fold with ≥5 attempts) 1
• The volume of CSF withdrawn (up to 30 mL) has no significant effect on the risk of post-LP headache 1
• More than 85% of post-LP headaches resolve without treatment 2
• Younger adults and women have higher risk of post-LP headache and may need closer monitoring 3, 2
• LP is particularly safe in older adults with cognitive impairment, with lower risks of complications than those with normal cognitive function 2

Common Pitfalls to Avoid

• Using cutting-bevel needles instead of atraumatic needles 1
• Making more than four attempts at dural puncture 1
• Active withdrawal of CSF through a syringe instead of gravity flow 1
• Keeping patients flat unnecessarily after the procedure, which may increase hospital stay without clinical benefit 3
• Failing to replace the stylet before withdrawing the needle 3