The small atraumatic needle method

As mentioned previously, using smaller, atraumatic needles decreases the incidence of post lumbar puncture headache. If you have chosen to perform this method, you will need to add two pieces of equipment to your LP tray: a small gauge Sprotte or Whitacre needle (I often use a 24 or 27 gauge) and a regular 18 gauge needle (the type you draw up medications with). Add these to you LP tray before beginning your procedure. What you will immediately notice is the small gauge needles are very flexible. This can lead to difficulty in directing the LP needle as it tends to flex and bend while being advanced through the soft tissues. To solve this problem, you will use the 18 gauge needle as a "guide" for the smaller, more flexible LP needle.

Begin the LP as you would normally, with positioning the patient, cleaning the sterile field, draping and anesthetizing the back. Once the patient is anesthetized, take your 18 gauge needle and place it between the two spinous processes as though you were using it as your LP needle (two thirds of the way caudal between the spinous processes, parallel to the bed and aimed at the umbilicus). Insert the needle up to its hub. The 18 gauge needle should feel firmly embedded in the ligaments when properly placed, yet it is too short to reach the spinal canal.

Now take your smaller LP needle and advance it through the 18 gauge needle. This guides the flexible LP needle towards the spinal canal while preventing it from bending. As with the regular LP, remove the stylet often as you advance, checking for CSF flow. You will often feel the 'pop' as you pass through the ligamentum flavum and dura mater signifying that you are in the correct space. Note that CSF flow will be slower due to the smaller needle, thus you will need a little more time for pressure measurement and CSF collection.