We often do lumbar puncture in the ED. Patients get warned about the potential of a post LP headache.
What is the prevalence of a post-LP headache?
The literature reports 15% of ED patients have a post LP headache.
How bad is it?
Most present in 3-7 days. Since the pain is postural, it impairs the patient's ability to perform activities of daily living (imagine trying to do everything lying down in bed!). Slim women aged 18-40 seem to be at the highest risk.
What will decrease incidence of post LP headache?
Pick the correct spinal needle.
The incidence of post LP headache:
- 20G cutting needle: 40%
- 25G cutting needle: 5%
- 22G atraumatic needle (smaller dural puncture, smaller CSF leak): 4%.
Trick of the Trade: 22G or 25G atraumatic spinal needle
The atraumatic spinal needles, also known as Sprotte needles, have a more blunt tip and often require a larger gauge needle to first puncture the skin. If using a 25G needle (which is a bit flimsy), I use a regular 18G needle to puncture the skin and soft tissue first (acting as a trocar), then I thread the 25G spinal needle through.
Great post Stella. Thanks for reminding us that sometimes it can be hard to do more good than harm. From now on I'll only use 25 G needles (we don't have atraumatic needles yet). Demian
ReplyDeleteWe don't have the atrauamtic needles available either. I hear the tradeoff is that it may be slightly more difficult to get CSF from a technical perspective. Will start using the smallest gauge needle we have though (I think it's a 22G). Great trick!
ReplyDeleteThanks Demian and Michelle,
ReplyDeleteOur LP trays contain the cutting needles still, so I usually ask the OR to send down a few atraumatic needles.
Another hint:
ReplyDeleteThe fibers of the dura run longitudinally, by orienting the bevel of the traumatic needle this way (i.e. pointin to either side, not up or down), the hole that is cut is supposed to be smaller, at least in theory. If using an atraumatic needle, this doesnt matter.
Along the lines of what Peter said, I have heard (probably no evidence) that if one re-inserts the sylet and twists the needle around one avoids pulling out neuronal fibers that keep the track open leading to the csf leak implicated in the post LP headache.
ReplyDeleteDemian