Investigations

Lumbar puncture ^a  

Use a narrow gauge, non-cutting needle ^a through a bleb of local anaesthetic ^c

Why?

Narrow gauge needles and non-cutting needles reduce post-lumbar puncture headache

Patient	Treatment	Comparison	Outcome	CER	OR (95% CI)	NNT (95% CI)
Adults undergoing lumbar puncture a	Small gauge needle	Large gauge needle	Post-lumbar puncture headache at weeks	11%	0.30 (0.20 to 0.41)	13 (12 to 16)
Adults undergoing lumbar puncture	Non-cutting needles	Cutting tip needles	Post-lumbar puncture headache at weeks	6.8%	0.50 (0.27 to 0.68)	31 (21 to 49)

Note:

• Non-cutting needles (with round tip) require an introducer needle to break the skin.
• Back pain and failure rates do not clearly differ with small, large, cutting or non-cutting needles ^d
• A bleb of lignocaine does not clearly reduce a successful first lumbar puncture attempt. ^c