Lumbar puncture

Question 1

How is lumbar puncture performed?

Answer 1

1. Place patient on left side with knees to chin
2. Landmarks: plane or iliac crests through level of L3/4 as spinal cord ends at L1/2
3. Use aseptic technique to clean skin and allow to dry, then place sterile drapes
4. Use orange needle to anaesthetise area, then use green needle to infiltrate deeper
5. Then insert spinal needle, aiming slightly upwards towards the umbilicus, feel resistance of spinal ligaments, and then the dura, then a ‘give as the needle enters the subarachnoid space. Keep bevel of needle facing upwards
6. Withdraw stylet, check CSF fills needle, and attach manometer (3-way tap) to measure opening pressure
7. Catch fluid in three sequentially numbered bottles
8. Reinsert stylet (stops CSF continuing to drip out), theln remove needle and apply dressing

Question 2

What is a bloody tap indicative of, and confirmed by? (x2)

Answer 2

Due to piercing a blood vessel, and indicated by fewer RBCs in successive bottles, and no yellowing of CSF. Can also be due to subarachnoid haemorrhage and indicated by no change in RBC content in each bottle.

Question 3

What are the indications for lumbar puncture?

Answer 3

Infectious, inflammatory, and neoplastic conditions

Question 4

What are the contraindications for lumbar puncture? (x4)

Answer 4

• Raised ICP (causes coning)
• Bleeding diathesis
• Cardiorespiratory compromise
• Infection at needle insertion site

Question 5

What are the complications of lumbar puncture? (x5)

Answer 5

• Post-dural puncture headache
• Infection
• Bleeding
• Cerebral herniation
• Minor/transient neurological symptoms such as paraesthesia or neuropathy. Note that pain, weakness, sensory changes, should be treated as cauda equina until proven otherwise