This procedure is performed to obtain a sample of cerebrospinal fluid.
Emergency department indications
A lumbar puncture is only indicated in the emergency department to diagnose or rule out:1
- CNS infection
- Subarachnoid hemorrhage in a patient with a negative CT scan
- Idiopathic intracranial hypertension
There are no absolute contraindications, and the risks of the procedure have to be considered since data regarding relative contraindications is lacking. Be cautious if your patient has:1,2
- thrombocytopenia, bleeding disorders or on anticoagulation
- concern for increased intracranial pressure
- suspected lumbar epidural abscess
- local infection at the puncture site
This video will walk you through all the steps (start at 1:52):
1. Obtain consent
2. Position the patient
3. Determine the puncture site
4. Clean the puncture site with antiseptic solution
5. Drape the skin
6. Infiltrate local anesthetic into the skin and deeper tissues overlying the target area
7. Introduce the spinal needle and advance horizontally aiming towards the umbilicus. Continue to advance until a pop is felt
8. Remove the stylet
9. Obtain an opening pressure if indicated
10. Collect the CSF fluid
11. Reinsert the stylet
12. Remove needle
13. Apply bandaid
Troubleshooting – a.k.a. where’s my fluid??
- be patient – fluid may drip very slowly, especially when using a longer needle
- if you feel the pop or are pretty sure you are (almost) there but fluid is not dripping, rotate the needle 45 degrees
- relax and step back for a moment. Look at the position of your patient. Has the patient turned or rotated? Are you entering in midline?
- this feels like bone…. withdraw to the subcutaneous tissue and redirect
- grab an ultrasound machine to help determine your landmarks (see tips & tricks below)
Place your patient in the lateral recumbent position with the knees to the chest or in an upright position, either bent over or with feet supported and the chest resting on the knees. There is no data to suggest that the success rate or complication rate is influenced by patient position. One study measured the interspinous distance in 3 positions and found that the interspinous distance was greatest in the upright position with feet supported.3
Depending on the availability in your hospital you can choose between a standard Quinckle needle and an atraumatic Sprotte or Pajunk. Use of atraumatic needles has been proposed to decrease post LP headaches. There is limited data to support this.2 Use of an atraumatic needle is associated with an increase in attempts, without increasing the risk of post LP backache. The size of the needle may have an effect on post LP headache, use a 22 gauge needle.4 Remember to choose the appropriate needle length in the obese population.
Reinsertion of stylet
Reinserting the stylet theoretically reduces the risk of post procedure leak of CSF and subsequent headaches. There is data to support this might be true: in a single study reinsertion of the stylet before withdrawal of the needle lead to a reduced risk of headache.5
Bed rest after procedure
Early mobilization is in, bedrest is out. There is data to support that immediate immobilization after LP decreases the risk of post LP headache when compared to bedrest.2
Unless your patient is dehydrated, there is no need to pre-hydrate your patient – it has not been proven that this leads to increased LP success or reduces the risk of post LP headaches.2
Overall complication rate is low.
Post LP headache – most common complication, in up to 30-60% of patients.2,6 Most likely occurs due to leakage of CSF due to a hole in the dura, causing a drop in CSF pressure with resultant traction on the brain and cerebral vasculature vasodilatation. As stated above, needle size, stylet reinsertion and early post procedure mobilization might help reduce the risk of post lumbar puncture headache. Number of attempts, volume or patient position do not influence the risk of headache. There is no great literature to support the use of IV caffeine to temporarily relieve headache after the procedure.7 There is limited data to support the use of a blood patch (injecting 10-30mL of the patient’s blood into the epidural space).8
Back pain – common, occurs in up to one third of patients, often persist for several days.1
Infection – this is a rare complication. Both local skin infections and meningitis can occur. The 2005 Healthcare Infection Control Advisory Committee recommends the use of facemasks when performing a lumbar puncture.1 Even though there is no data to support that facemasks prevent infection, it seems reasonable, cheap and easy to wear a mask while performing the procedure.
Bleeding – can occur in the subcutaneous tissue as well as in the subarachnoid space, the latter is rare.
Minor neurologic symptoms – these are transient, often resolve with withdrawal or repositioning of needle.
Cerebral herniation – increased intracranial pressure alone does not cause herniation.9,10 Think about it: your pseudotumor cerebri patient is actually treated with a tap, and they never herniate.11 However, a space occupying lesion with midline shift can cause herniation after a lumbar puncture. There is no data to suggest that this is a causal relationship: in these patients herniation most likely occurs regardless of the LP.9 Be cautious in this patient population – a very careful, case by case consideration should be made if you are considering a tap.
Epidermoid tumors of the thecal sac – rare, late complication. Prevented by using a tight fitting stylet while puncturing the skin.1
You got it! Tips, tricks & continued FOAM-ing while sipping champagne
- Academic Life in Emergency Medicine – Trick of the trade EMLA for lumbar punctures
- R.E.B.E.L. EM – Post Lumbar Puncture Headache
- Pediatric EM Morsels – Traumatic lumbar puncture
- The Skeptics Guide to Emergency Medicine – SGEM#34:This is Spinal Tap (Lumbar Punctures)
- 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.
- Sonocloud – Probe position: ultrasound assisted lumbar puncture
- The BMJ – Ultrasound imaging for lumbar punctures and epidural catheterizations: systemtic review and meta-analysis
- Crashing Patient – Herniation from Lumbar Puncture
4. Tourtellotte WW, Henderson WG, Tucker RP, Gilland O, Walker JE, Kokeman E. A randomized double-blind clinical trial comparing the 22 versus 26 gauge needle in the production of the post-lumbar puncture syndrome in normal individuals. Headache. 1972;12:73-78
7. Halker RB, Demaerschalk BM, Wellik KE, Wingerchuk DM, Rubin DI, Crum BA, Dodick DW. Caffeine for the prevention and treatment of postdural puncture headache: debunking the myth. Neurologist. 2007 Sep;13(5):323-7.
Written by: Maite Huis in ‘t Veld, M.D. | Peer reviewed by: Michael Abraham, M.D.,M.S. | September 11th, 2014