Procedure: Lumbar Puncture

Procedure, instructions and discussion

Lumbar Puncture

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Instructions

Indications

• CNS infection suspected (Meningitis, encephalitis)

Or

• Subarachnoid haemorrhage suspected (12 hours post headache onset and after normal CT brain)

Contraindications (ABSOLUTE/relative)

• INR >1.5, HEAPAIN/NOAC < 12 hrs, PLATLETS <100
• SUSPECTED RAISED ICP (reduced LOC)
• Haemodynamic instability
• Trauma to lumbar vertebrae
• Overlying skin infection

Alternatives

• Defer lumbar puncture (Without delay in clinical treatment)
• CT angiogram in suspected subarachnoid haemorrhage (Identify aneurysms, with risk of false positives)

Consent

WRITTEN – IF HAS CAPACITY

• Complex procedure with a higher risk of complications
• If unable to sign document witnessed verbal consent

NOT REQUIRED – IF LACKS CAPACITY

• Emergency procedure to prevent serious injury

Potential complications

• Failure to obtain CSF
• Back pain and radicular pain (20%)
• Headache (20% with 22g needle)
• Bleeding (epidural or soft tissue haematoma)
• Infection (meningitis, epidural, discitis, osteomyelitis)
• Nerve damage
• Epidermoid tumours
• Cerebral herniation

Infection control

• Standard precautions
• PPE: sterile gloves, sterile gown, surgical mask

Area

• Monitored bed space

Staff

• Procedural clinician
• Assistant

Equipment

LP NEEDLE & INTRODUCER NEEDLE

• 22 or 25G atraumatic (pencil point) spinal needle 90mm
• 22G if measuring opening pressure
• 25G if not measuring opening pressure
• Commonly brands are Sprotte or Whitacre
• The introducer needle is a sharp bevelled cutting needle

LONGER SPINAL NEEDLE IN RAISED BMI

• BMI 25-35 likely to require 120mm needle
• BMI >35 likely to require 150mm needle

LUMBAR PUNCTURE SET

• Manometer
• 3-4 collecting tubes

ULTRASOUND OPTIONAL

• Measure depth of ligamentum flavum and guide needle

Positioning sitting (preferred)

• Patient sits on edge of bed
• Chair supporting feet
• Hips at greater than 90 degrees flexion
• Patient leans forward, hugging a pillow
• Maximal flexion of lumbar spine
• Opening pressure cannot be measured sitting

Positioning lying down

• Patient lying on side with back to edge of bed
• Patients hips at maximum tolerable flexion
• Ensure knees are together and shoulder not rotated
• Aim to position lower back in vertical plane
• If unconscious an assistant maintains spinal flexion
• Opening pressure is measured in lying position

Medication

• Lignocaine 1% 5mls (max 3mg/kg)
• Consider midazolam 1-2mg IV titrated to anxiolysis
• Consider morphine 2.5-5mg IV pain relief
• Consider ketamine 10-20mg IV pain relief and sedation

Sequence (Locating space)

• Identify iliac crests (L4-5)
• Palpate midline at this level (or space above (L3-4)
• Palpate interspinous space
• Mark skin with a needle cap
• Use sustained pressure for 5-10 seconds

Sequence (US location of space)

• Select curvilinear probe (abdominal) probe
• Orient probe vertically lateral to midline
• Identify spinous processes and space between
• Identify ligamentum flavum and estimate distance

Sequence (Lumbar puncture)

• Confirm landmarks
• Infiltrate with local anaesthetic subcutaneously
• Infiltrate deeper down to interspinous ligament
• Insert cutting introducer needle at midline
• Aim in between spinous processes, towards the umbilicus (slightly cephalad)
• Insert 3 cm to allow tissues to maintain insertion axis
• Insert the lumbar puncture needle through the introducer
• Maintain constant pressure feeling for increased resistance (ligamentum flavum)
• Remove stylet and check for CSF flow (allow 5-10 seconds)
• If no flow advances atraumatic needle 2-3 mm without stylet
• Re-check for CSF flow (allow 5-10 seconds)
• Repeat small slow advances until flow of CSF is obtained
• You may feel a release of pressure once past ligamentum flavum
• You may feel a “pop” when going through dura
• Once CSF flow is identified collect a sample (15 drops per tube)
• You may use the stylet to control flow between samples
• Once samples collected reinsert stylet fully
• Remove introducer and LP needle complex together
• Apply sterile dressing to site

Sequence (Failure (bone resistance))

• If bone resistance is felt remove the LP needle
• Remove introducer until the tip is sub cutaneous
• Increase introducer incline angle 5-10 degrees
• Re-insert introducer and atraumatic needle
• If resistance felt again repeat in the opposite direction

Sequence (Radicular pain)

• If radicular pain occurs during LP insertion
• Remove introducer until the tip is sub cutaneous
• Adjust angle 5-10 degrees away from affected leg
• Re-insert introducer and atraumatic needle

Sequence (Measuring opening pressure, lying position only)

• After flow of CSF achieved measure pressure
• You may use the stylet to control flow
• Attach manometer
• Hold zero marker at needle level
• Position manometer vertically
• Allow CSF to rise and create a vertical fluid column in the manometer
• Wait until level stable and measure
• Disconnect and empty manometer into first sample

Post-procedure care

Send CSF for from following testing

XANTHOCHROMIA

• Bilirubin by spectrophotometry
• Protect from light in transport

CSF MICROSCOPY, CULTURE, CELL COUNT, PROTEIN, GLUCOSE

CONSIDER PCR TESTING FOR SPECIFIC INFECTIONS

• Neisseria meningitides
• Herpes simplex
• Varicella zoster
• Enterovirus

Patient may mobilise (no benefit to bedrest)

Document (completion, attempts and complications)

Tips

• Pencil point needles cause less post-LP headache than bevelled needles
• We recommend introducer needles to aid pencil point passage through the dermis and the interspinous ligament
• If only bevelled needles are available, orient the bevel laterally to split longitudinal fibres and minimise trauma
• Small needles (25G) have lower complication rate and are generally recommended
• Larger needles (22G) have a greater flow rate and are required if measuring opening pressure
• Moving patient from lying to sitting with the needle in situ (to measure opening pressure) is not recommended
• Simple analgesia is the initial treatment for a post-LP headache
• Bed rest and patient position do not affect the incidence of post-LP headache
• NSAIDs do not increase the risk of epidural haematoma with lumbar puncture
• Lumbar puncture with coagulopathies carries a 2% chance of epidural haematoma with risk of paralysis
• Advancing an inserted needle without the stylet improves success without increasing risk of epidermoid tumour

Discussion

Atraumatic needles are now strongly recommended for lumbar puncture due to their clear safety benefits. A large meta-analysis of over 31,000 patients showed they significantly reduce post-dural puncture headache (PDPH) and other complications, without compromising procedural success. These findings support their routine use in clinical practice.

Severe complications from LP are rare. In a large feasibility study, only 0.3% of patients required an epidural blood patch, and 0.7% were hospitalised. Risk factors for post-LP symptoms included a history of headache, anxiety, use of cutting needles, larger gauge needles (<22G), and multiple attempts. The likelihood of back pain increases significantly with increased attempts.

Cerebral herniation is an uncommon but potentially fatal complication. The highest risk is in patients with mass lesions or posterior fossa abnormalities causing pressure gradients. Pre-procedure imaging is essential in the following groups:

• REDUCED LEVEL OF CONSCIOUSNESS
• AGE > 60 YRS
• IMMUNOCMPROMISED STATE
• FOCAL NEUROLOGICAL FINDING
• HISTORY OF CNS LESION
• SEIZURE ACTIVITY WITHI PRECEDING DAYS

Imaging findings like midline shift or cisternal effacement are absolute contraindications to LP.

Bleeding risk must be assessed carefully in patients on anticoagulants or antiplatelet agents. Aspirin alone carries a low risk, but dual antiplatelet therapy and anticoagulants (e.g., warfarin, NOACs, heparin) increase spinal bleeding risk which can cause paralysis. INR should be <1.5 and platelets >40 × 10⁹/L before LP.

Optimal needle selection balances safety and practicality. A 22G atraumatic needle is commonly used. Smaller bore needles (>24G) reduce complications but can slow CSF flow. More than four attempts should be avoided to reduce back pain and bruising.

References

• Engelborghs S et al. Consensus guidelines for lumbar puncture in patients with neurological diseases. Alzheimers Dement (Amst). 2017 May 18;8:111-126.
• Nath S et al. Atraumatic versus conventional lumbar puncture needles: a systematic review and meta-analysis. Lancet. 2018 Mar 24;391(10126):1197-1204.
• Domingues R, Bruniera G, Brunale F, Mangueira C, Senne C. Lumbar puncture in patients using anticoagulants and antiplatelet agents. Arq Neuropsiquiatr. 2016 Aug;74(8):679-86.
• Zorrilla-Vac A. Effectiveness of Lateral Decubitus Position for Preventing Post-Dural Puncture Headache: A Meta-Analysis. Pain Physician 4, no. 20;4 (2017/5/10/ 2017): E521-E29.
• Kim K. Lumbar Puncture: Considerations, Procedure, and Complications. encephalitis 2022
• McGill F, Heyderman RS, Michael BD, Defres S, Beeching NJ, Borrow R, Glennie L, Gaillemin O, Wyncoll D, Kaczmarski E, Nadel S, Thwaites G, Cohen J, Davies NW, Miller A, Rhodes A, Read RC, Solomon T. The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults. J Infect. 2016 Apr;72(4):405-38
• Doherty CM, Forbes RB. Diagnostic Lumbar Puncture. Ulster Med J. 2014 May;83(2):93-102.
• Butson B, Kwa P. Lumbar puncture. Emerg Med Australas. 2014 Oct;26(5):500-1. 
• Holdgate A, Cuthbert K. Perils and pitfalls of lumbar puncture in the emergency department. Emerg Med (Fremantle). 2001 Sep;13(3):351-8
• llenby MS, Tegtmeyer K, Lai S, Braner DA. Videos in clinical medicine. Lumbar puncture. N Engl J Med. 2006 Sep 28;355(13):e12.
• Johnson KS, Sexton DJ. Lumbar puncture: Technique, indications, contraindications, and complications in adults. In: UpToDate. Waltham (MA): UpToDate. 2018 June 2. Available from: https://www.uptodate.com/contents/lumbar-puncture-technique-indications-contraindications-and-complications-in-adults
• Sydney Children’s Hospital Network. Lumbar puncture practice guideline. Sydney: SCHN; 2019. 12pp. Guideline 2014-9039 v5.
• The Royal Children’s Hospital Melbourne. Lumbar puncture. n.d.
• Arevalo-Rodriguez I, Ciapponi A, Roqué i Figuls M, Muñoz L, Bonfill Cosp X. Posture and fluids for preventing post-dural puncture headache. Cochrane Database Syst Rev. 2016 Mar 7;3(3):CD009199.
• Arevalo-Rodriguez I, Muñoz L, Godoy-Casasbuenas N, Ciapponi A, Arevalo JJ, Boogaard S, Roqué I Figuls M. Needle gauge and tip designs for preventing post-dural puncture headache (PDPH). Cochrane Database Syst Rev. 2017 Apr 7;4(4):CD010807.
• Baxter AL, Fisher RG, Burke BL, Goldblatt SS, Isaacman DJ, Lawson ML. Local anesthetic and stylet styles: factors associated with resident lumbar puncture success. Pediatrics. 2006 Mar;117(3):876-81. doi: 10.1542/peds.2005-0519.
• Hudgins PA, Fountain AJ, Chapman PR, Shah LM. Difficult Lumbar Puncture: Pitfalls and Tips from the Trenches. AJNR Am J Neuroradiol. 2017 Jul;38(7):1276-1283. 
• Hasbun R, Abrahams J, Jekel J, Quagliarello VJ. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. N Engl J Med. 2001 Dec 13;345(24):1727-33.
• April MD, Long B, Koyfman A. Emergency Medicine Myths: Computed Tomography of the Head Prior to Lumbar Puncture in Adults with Suspected Bacterial Meningitis – Due Diligence or Antiquated Practice? J Emerg Med. 2017 Sep;53(3):313-321.
• Domingues R, Bruniera G, Brunale F, Mangueira C, Senne C. Lumbar puncture in patients using anticoagulants and antiplatelet agents. Arq Neuropsiquiatr. 2016 Aug;74(8):679-86.
• Nayate AP, Nasrallah IM, Schmitt JE, Mohan S. Using Body Mass Index to Predict Needle Length in Fluoroscopy-Guided Lumbar Punctures. AJNR Am J Neuroradiol. 2016 Mar;37(3):572-8.

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