<qa>  What is the lignocaine 2 2-3ml?When the preferred lumbar interspace is in view on monitor, local anaesthetic lignocaine 2 2-3ml will be infiltrated to the skin and underlying tissue 1-2 cm lateral to the identified spinous process. Under real-time ultrasound guidance, a spinal needle introducer is then inserted in-plane to the ultrasound probe, followed by A 25G Pencan pencil point spinal needle. 