Lumbar Puncture

Kalpesh Patel, MD

Dept. of Pediatric Emergency Medicine

December 6, 2006

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Objectives

To learn the indications and contraindications for performing lumbar puncture

To learn lateral decubitus and sitting procedure for lumbar puncture

To learn the median and paramedian approach To review complications that can occur with lumbar

puncture, their precautions and treatments

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History

CSF first examined in 19th century using primitive techniques (sharpened bird quills)

Modern technique first performed by Quincke in 1890 on a small child and has changed little since then

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Indications

To obtain CSF for the diagnosis of:• Meningitis• Meningoencephalitis• Subarachnoid hemorrhage• Malignancy – diagnosis and treatment• Pseudotumor Cerebri• Other neurologic syndromes

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Contraindications

Unstable patient with cardiovascular or respiratory instability

Localized skin/soft tissue infection over puncture site

Evidence of unstable bleeding disorder• Platelets < 50,000 or clotting factor deficiency

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Contraindications

Increased intracranial pressure • Head CT before study if focal neurologic findings

present to rule out impending cerebral mass herniation

• Normal CT does not preclude intracranial HTN• Do not delay antibiotics to obtain imaging studies

when bacterial meningitis is strongly suspected Neurologic deterioration can occur if LP is done

below the level of a complete spinal subarachnoid block

Caution in patients with Chiari malformations

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Equipment

Most CSF trays come with:• Anesthetic such as:

Topical - EMLA, Elamax, Zylocaine cream

Lidocaine 1% with 25 gauge needle and syringe

• Povidone-iodine solution & sponge wand• Drapes, gauze, and bandages• Manometer, stopcock and tubing in non-

infant kits

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Equipment

Spinal needle, usually 22 gauge• 1.5 in for < 1 yr• 2.5 in for 1 year to

middle childhood• 3.5 in for older

children and adolescents

• Larger for large adolescents

Atraumatic needles, less spinal headaches

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Lateral Decubitus Position

Apply topical anesthetic 30-45 min prior to procedure Spinal cord ends at L1-L2, so sites for puncture are

located at L3-L4 or L4-L5 Restrain patient in lateral decubitus position

• Maximally flex spine without compromising airway

• Keep alignment of feet, knees and hips

• Position head to left if right handed or vice versa

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Procedure

Cleanse skin with povidone iodine from puncture site radially out to 10 cm and ALLOW TO DRY

Drape below patient and around site with fenestrated drape

Anesthetize with lidocaine if topical not used by:• Intradermally raising a wheal at needle insertion

site• Advance needle through wheal to desired

interspace Careful not to inject into a blood vessel or

spinal canal

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Procedure

Insert spinal needle with stylet with bevel up to keep cutting edge parallel with nerve and ligament fibers

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Procedure

Aim towards umbilicus directing needle slightly cephalad

Hold needle firmly

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Procedure

A “pop” of sudden decrease in resistance indicates that ligamentum flavum and dura are punctured

Remove stylet and check for flow of spinal fluid

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Procedure

If no fluid, then:• Rotate needle 90°• Reinsert stylet and advance needle slowly

checking frequently for CSF Jugular vein compression can increase CSF

pressure in low flow situations If bony resistance is felt immediately then you are

not in the spinal interspace If bony resistance is felt deeply, then withdraw

needle to the skin surface and redirect more cephalad and increase patient flexion

If bloody fluid that does not clear or that clots results, then withdraw needle and reattempt at a different interspace

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Manometry

When CSF flows, attach manometer to obtain opening pressure if desired

Pressure can only be accurately measured in lateral decubitus position and in the relaxed patient

Attach manometer with a 3-way stopcock when free flow of CSF is obtained

Read column when highest level is achieved and respiratory variation is noted

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Procedure

Collect 1ml of CSF in each of 3 vials for:• Tube 1: culture & gram stain• Tube 2: glucose, protein• Tube 3: cell count & differential• and extra CSF if desired for other lab tests

Check closing pressure with manometer, if desired Reinsert stylet and remove needle in one quick

motion Cleanse back and cover puncture site

LP The Movie

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Sitting Position

Restrain infant in the seated position with maximal spinal flexion• Hold infant’s hands between

flexed legs with one hand and flex head with the other hand

Drape patient below buttocks and fenestrated drape opening over puncture site

Insert needle so bevel is parallel to spinal cord (Bevel left or right)

Cannot measure pressure accurately in this position

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Paramedian (Lateral) Approach

Use for patients who have calcifications from repeated LPs or anatomic abnormalities

Needle passes through erector spinae muscles, and ligamentum flavum• Bypasses

supraspinal and interspinal ligaments

Less incidence of spinal headache

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Complications

Headache • Uncommon in < 10 y/o

Apnea (central or obstructive) Back pain

• Occasionally with short-lived referred limp• Disc herniation if needle advanced too far

Bleeding or fluid leak around spinal cord Infection, pain, hematoma Subarachnoid epidermal cyst Ocular muscle palsy (transient) Nerve Trauma Brainstem herniation

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Spinal Headache

Most common complication Risk factors: female, age 18-30, lower BMI, hx of

HA, prior spinal HA Bilateral HA, improves when supine Can last hours to weeks Supine position for at least 2 hours Hydration Caffeine either PO or IV Epidural blood patch

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Spinal Headache Prevention

Can avoid by:• Passing needle bevel parallel to longitudinal

fibers of dura• Replacing stylet before removing needle• Using small diameter needles• Using atraumatic needles

Bed rest or PO intake after LP does not reduce incidence of headache

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Nerve Root Trauma/Irritation

Can feel electric shocks or dysesthesias Back pain can persist for months

• Consider disc herniation Rarely permanent Withdraw needle immediately If pain or motor weakness persists, start

corticosteroids Electromyogram/nerve conduction velocity studies

should be scheduled if pain persists

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Herniation

Manifests initially as altered mental status, followed by cranial nerve abnormalities and Cushing triad

May be rapidly fatal. Immediately remove needle and raise the head of

bed to 30-45° improve venous return from the brain. Mannitol or 3% Saline Intubate patient and hyperventilate Emergent neurosurgical consult

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Epidermal Inclusion Cyst

Very rare due to use of stylet Occurs when a core of skin is driven into spinal or

paraspinal space with hollow needle Do not remove stylet until through the skin

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Failure of Procedure

If sample of CSF is critical several alternatives are available:• Have someone else try

Anesthesia Neurology

• Bedside ultrasound for difficult LPs

• Radiographic guided procedure Fluoroscopy Ultrasound CT

• Cisterna Magna tap

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Questions?

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Bibliography

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Robertson J, Shilkofski N. The Harriet Lane Handbook Seventeenth Edition. Elsevier Mosby. 2005. p86-88.

King C, Henretig Fred. Pediatric Emergency Procedures. Lippincott Williams & Wilkins 2000. p 124-128.

Straus SE, Thorpe KE, Holroyd-Leduc J. How do I perform a lumbar puncture and analyze the results to diagnose bacterial meningitis? JAMA. 2006 Oct 25;296(16):2012-22.

Peterson MA, Abele J. Bedside ultrasound for difficult lumbar puncture. J Emerg Med. 2005 Feb;28(2):197-200.

Runza M, Pietrabissa R, Mantero S. Lumbar Dura Mater Biomechanics: Experimental Characterization and Scanning Electron Microscopy Observations. Anesthesia and Analgesia. 1999;88:1317-21.

Sucholeiki R, Waldman A. Lumbar Puncture (CSF Examination). E-medicine. 2006 http://www.emedicine.com/neuro/topic557.htm.

Walter K. Manual of Common Bedside Surgical Procedures Second Edition. Lippincott Williams & Wilkins 2000. p181-186.

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Evans RW. Special Report: Complications of Lumbar Puncture and Their Prevention with Atraumatic Lumbar Puncture Needles. Medscape 2000. http://www.medscape.com/viewarticle/420288.