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Lumbar Puncture

Lumbar Puncture Learning Module

This web page is composed of six sections designed to re-familiarize practitioners with the Lumbar Puncture procedure.

Print all the necessary documents here or at other points throughout the module.
*Note: This module does not replace medical training and must be used in conjunction with clinical judgment. Acting practitioner is ultimately responsible for the safety of procedures.

1% lidocaine without epineprhine

SoluPrep Sterile Swabs

Collection Bottles

Sterile Gloves

REF 8605

Spinal Needle

Vacuum Bottle

REF S55120

Principle Risks

  • Post lumbar puncture headache5 - 36.5%
  • Hematoma< 0.1%
  • Infection< 0.1%
  • Pain at insertion siteVariable

Rare Risks

  • Neuronal Injury
  • Vasovagal reaction
  • Anaesthetic/sedative reactions
  • Subarachnoid epidermal cyst formation
  • Print Consent Form


  • Active skin infection over site
  • Signs of cerebral herniation
  • Signs of increased intracranial pressure
  • Extremis/Respiratory compromise that does not allow proper positioning
  • Indwelling lumbar hardware


  • INR > 1.5
  • Platelet < 50,000/mm3
  • Previous lumbar surgery
  • Recent antiplatelets or anticoagulants

Because of the extremely serious implications of spinal hematomas, conducting LPs on patients with uncorrected coagulopathy or thrombocytopenia is very rare, and only done out of absolute necessity

CT scan should be performed prior to lumbar puncture if there is any possibility of increased ICP; However, CT is not a perfect test and does not replace clinical evaluation of high ICP

Essential Investigations

  • Microbiology
    • Gram Stain
    • Culture and Sensitivity
  • Biochemistry
    • Glucose
    • Protein
    • LDH
  • Hematology
    • Cell Count
    • Differential

Targeted Investigations

  • Extended Microbiology
    • Viral PCRFor specified viruses, usually HSV and VZV
    • AFB Testing
    • Fungal Cultures
    • Cryptococcal antigen
  • Cytology
    • Yield is best when sending large volume (5-10ml)
  • Flow Cytometry
    • Must be a separate sample from cytology
  • Other
    • Oligoclonal BandsSent at the same time as serum oligoclonal bands for suspicion of MS
    • Paraneoplastic antibodies
Print Procedure Note


  • Patient can be positioned in the sitting or lateral recumbent position
  • Patient should arch or flex back

2Landmark manually

  • Palpate the top of the iliac crests bilaterally
  • Following your hands to the midline, palpate the spinal process of L4
  • Identify and mark the desired interspace
  • L3-L4, L4-L5, or L5-S1 can all be utilized.


  • Visualize the effusion and remark needle insertion site

4Sterilizing and anaesthetizing

  • Sterilize the area 3 times utilizing antiseptic
  • Dress with sterile gloves and apply a sterile drape
  • With a 25 gauge needle, inject a ‘wheel’ of lidocaine into the dermis overlying the prospective needle insertion site

5Introduce the spinal needle

  • Bevel should be in the saggital plane, parallel with the direction of dural fibers
  • Angle needle tip 10-15° cephelad
  • After traversing the ligamentum flavum (may feel a ‘pop’ or ‘give’), remove the stylet to determine if CSF is flowing. If not, advance by 2mm increments, removing the stylet each time, until fluid is obtained
  • If bone is encountered, withdraw the needle to the subcutaneous space and re-advance.

6Opening pressure and obtaining fluid

  • To obtain an opening pressure, attach the monometer to the hub of the spinal needle. The measurement is taken once the CSF rises to it’s peak position.
  • Turning the stop-cock towards the patient will let you drain the CSF in the monometer into a collection tube
  • Collect CSF by allowing it to drip from the spinal needle into the collection tubes
  • Replace the stylet before withdrawing the spinal needle

7Post procedure care

  • Place clean bandage over procedural site
  • Order post-procedure vitals
  • Documentation sheet must be in the chart!


All specimens should be hand-delivered to their destinations

Ellenby, Miles S., et al. “Lumbar puncture.” New England Journal of Medicine355.13 (2006): e12.
Kind thanks to Sonosite for their permission.

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