technique

Last reviewed 01/2018

The technique for obtaining cerebrospinal fluid is as follows:

  • position the patient:
    • if right-handed, move the patient to the edge of the bed on their left side
    • there should be maximal flexion of the thoracolumbar spine; a pillow is placed between the knees of the patient to prevent torsion of the spine

  • the interspace to be used for the lumbar puncture:
    • the adult spinal cord ends at the level of L1-2
    • the plane of the iliac spine runs through L3-4; L3-4 or L4-5 space can be used

  • technique of lumbar puncture:
    • put gloves on
    • put a drape on top of the patient
    • clean the area e.g. with betadine
    • anaesthetise the skin and subcutaneous tissues with lignocaine at the chosen site
    • place the spinal needle in the interspace with the bevel uppermost and advance it towards the umbilicus keeping it parallel to the ground
    • when advancing the needle consider:
      • there is an increase in resistance as the needle pierces the tough ligamentum flavum and a marked reduction of resistance as the needle passes through
      • when through the ligamentum flavum, the dura is very close (1-2 mm away) and the needle should be advanced carefully and the stylet withdrawn after each step
      • when the dura is pierced there should be a free flow of cerebrospinal fluid
    • measure the opening pressure with a manometer