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Procedural Steps
Preparation
Patient Positioning
Landmarking
Site Preparation
Local Anesthesia
Needle Insertion
Collection of CSF
Removal of Needle
Post-procedural Care
Interpretation of Results
CSF Pressure
Measurements

Quiz
LP Pressure Quick Guide





Check the spinal needle to ensure the stylet slides in and out easily. Recheck your landmarks and make sure the patient's position has not shifted. Warn the patient that a feeling of pressure or an odd sensation in the back may occur.

When using the standard cutting needle, insert the needle at the identified site with the bevel facing upward (if the patient is in the left or right lateral position). The bevel is thus directed in the horizontal plane (parallel to the axis of the spine) ensuring that the bevel is parallel to the dural fibres.

Direct the needle at an angle of approximately 10 degrees cephalad.

Since the line of site from your eye to the point of needle insertion will probably be tilted downwards (i.e. your head is above the midline), there will be a tendency to insert the needle in a downward angle. Resist this temptation.

Advance the needle approximately 1.5 inches or until a slight "pop" is felt as the dura is penetrated. At this point, remove the stylet and wait 2 seconds for CSF drainage. If there is no CSF return, advance the needle 1-2 mm. at a time, checking for CSF return with each advance and thus avoiding going through the ventral epidural space and the venous plexus there. If the needle tip encounters solid obstruction (bone), withdraw the needle tip to just below the skin, check your landmarks and patient positioning and advance the needle again.

Failure to obtain a CSF return may be related to improper positioning of the patient (not perpendicular to the bed or curled enough), or the insertion point may be off the midline or because the needle may be directed too far caudally.

If frank blood drips from the needle after the stylet is withdrawn then discard this needle and try again, perhaps at another space.

The ligamentum flavum in a young and fit individual is firm - the sensation is similar to that of pushing a needle through an eraser – whereas bone is very hard and will not give and the patient may complain of pain if the needle touches bone.
   

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