Certainly, one of the most common procedures in the Ped ED is the lumbar puncture. We have discussed efforts to ensure that our first attempt is our best attempt: good positioning and analgesia are critical. We have also discussed how to deal with the result when the LP was traumatic. Additionally, we have covered the complication of Post-LP Headaches. One question we should ask though is… are we undermining our own success rate? Do we need to keep replacing the Spinal Needle Stylet? Does playing the LP Hokey Pokey help or hurt us?

Anatomy Matters

One major goal of the Lumbar puncture is to obtain an atraumatic tap (AKA “Champagne Tap”) An aside – What “Champagne tap” means is often debated Does it just reference Zero RBCs , or does it also have to have No leukocytes? Is it for every LP you do? Or just the first time you do one? Who is to say? Generally the person buying the bottle of champagne is the one to make “the rules.” Having an atraumatic tap will make interpretation and management more clear . (Clear fluid => clear decisions) See Traumatic Tap Morsel for reasons why you should NOT adjust your CSF results in an attempt to interpret CSF with lots of RBCs.

(AKA “Champagne Tap”)

Landmarks: [Bonadio, 2014] Superior Iliac Crest Supracristal line Horizontal line connecting superior portion of superior iliac crests. Intersects the spinal column at the L3-L4 interspace . Whether in the lateral decubitus position or the seated position (See Morsel as to why you may want to favor the seated position), ensure the spinal column and the supracristal line are perpendicular to each other.



Spinal Cord terminates around level of L1.

Venous plexus Surrounds the dura lining. Ventral to the subarachnoid space the plexus is extensive. Important not to “over-shoot” the subarachnoid space as you will likely encounter the extensive venous plexus that is ventral to it. [Bonadio, 2014] Using a stylet can cause you to inadvertently over-shoot, as you blindly advance the needle and may advance through the lumbar cistern and enter the venous plexus that is ventral to it.



Spinal Needle Stylet: Why Use It?

If using a stylet may make it more likely to have a traumatic LP, then why use it at all?

There are cases of intraspinal epidermoid tumors arising related to LPs. [Ziv, 2004]

arising related to LPs. [Ziv, 2004] The hollow tip of a needle can, potentially, carve out a plug of epidermis or dermis and then translocate that into the subarachnoid space.

and then translocate that into the subarachnoid space. The stylet converts a hollow bore needle into a solid one, thus, preventing a plug of skin being carved out and transplanted.

Spinal Needle Stylet: Not a Dance

Obviously, if we want to avoid creating a complication like epidermoid tumors, we need to use the spinal needle stylet ; however, this often has lead to an interesting dance : Inserting the stylet, advancing the needle, removing the stylet, checking for CSF, reinserting the stylet, advancing again, and repeating “You put the stylet in. You put the stylet out. You put the stylet in and … you hope you get CSF and not blood” (ok, not the best dance song).

; however, this often has lead to : Two main issues exist with the “Stylet Hokey Pokey:” 1st – The “pop” sensation of piercing the inner ligaments is not as prominent in children as adults, so having the stylet in position can lead to over-inserting the needle and entering the ventral venous plexus… and turning champagne into fruit punch . 2nd – The stylet is, itself, sharp. Repeatedly reinserting it also increases the potential for inadvertently sticking your self with it.



Spinal Needle Stylet: Best of Both Worlds

There is a way to both minimize the risk of causing epidermoid tumor AND minimize risk of a traumatic LP . [Bonadio, 2014; Baxter, 2006; Strupp, 1997] Appropriately position the child and ensuring adequate analgesia and sterile prep. Insert the spinal needle through the epidermis and dermis with the stylet in place . Once through the dermal layers (< 1cm), remove the stylet and advance slowly without the stylet . Stop once CSF is seen to flow into the hub of the spinal needle. Rejoice.

. [Bonadio, 2014; Baxter, 2006; Strupp, 1997] The stylet should be reinserted prior to removing the spinal needle completely to help minimize post-LP headaches.

References