Citation, DOI, disclosures and article data
Citation:
Knipe H, O'Shea P, Dry tap (lumbar puncture). Reference article, Radiopaedia.org (Accessed on 30 Apr 2024) https://doi.org/10.53347/rID-177467
Disclosures:
At the time the article was created Henry Knipe had the following disclosures:
- Integral Diagnostics, Shareholder (ongoing)
- Micro-X Ltd, Shareholder (ongoing)
These were assessed during peer review and were determined to
not be relevant to the changes that were made.
View Henry Knipe's current disclosures
A dry tap refers to a lumbar puncture where cerebrospinal fluid (CSF) cannot be obtained despite the needle tip being in the thecal sac 1. Dry taps may be associated with needle misplacement or blockage, dehydration, low CSF pressure, severe spinal canal stenosis (including epidural lipomatosis), and arachnoiditis 1-3.
Practical points
Troubleshooting a dry tap requires patience as CSF flow can be slow. Methods can include 1,2:
gentle coughing or Valsalva maneuver
re-insert and remove the stylet
fluoroscopic table head-up tilt of 45 degrees
rotate the needle in 90-degree increments waiting between rotations
advance the needle by 1-2 mm
gentle intermittent suction with a 10 mL syringe
iodinated contrast can be injected to confirm intrathecal needle placement
repeat lumbar puncture after rehydration
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1. Hudgins P, Fountain A, Chapman P, Shah L. Difficult Lumbar Puncture: Pitfalls and Tips from the Trenches. AJNR Am J Neuroradiol. 2017;38(7):1276-83. doi:10.3174/ajnr.a5128 - Pubmed
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2. Kachulis B, Tsiouris A, Nelson P, Stadnyk I. Dry Spinal Tap. Journal of Neuroanaesthesiology and Critical Care. 2020;08(01):082-3. doi:10.1055/s-0040-1715358
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3. Gong X, Xu J, Wang J. Low Tension of the Dural Sac as a Cause of Unsuccessful Myelography in Spontaneous Intracranial Hypotension: Evidence from Computed Tomographic-Guided Myelography. Neurol India. 2018;66(2):518. doi:10.4103/0028-3886.227307 - Pubmed
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