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the ligamentum flavum, the dura is very close (1-2 mm away) and the needle should be advanced carefully and the stylet withdrawn after each step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