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

LP Pressure Quick Guide

Many patients may be too ill to sit upright for LP. The patient should be positioned in a left lateral (for a right handed physician) or right lateral position (for a left handed physician) for LP.

The patient should curl into a fetal position, placing the lumbar spine in maximal flexion. It may help to support the upper arm to prevent the upper shoulder from rolling forward. This will in turn create the greatest interspinous distance (opens the gap) through which to access the intrathecal space.

The patient's back should be at the edge of the bed to allow collection of fluid easily. A pillow under the head will provide comfort and keep the spine in a horizontal plane. The shoulders, back and hips must be perpendicular to the horizontal plane. Incorrect positioning initially will lead to the spinal needle deviating from the midline after introduction. This is one of the most common reasons for an unsuccessful tap.

When the patient is instructed to “curl up”, the patient’s upper shoulder may "roll forward”. The lower shoulder's ability to move forward may also be restricted if the entire patient’s weight is upon it. Gently push the lower shoulder in an anterior direction as far as the patient is able to tolerate comfortably, then move the upper shoulder to relatively the same position.

An alternative method of positioning involves placing the patient in an upright seated position. This can be particularly useful in patients with whom there is difficulty in landmarking the needle insertion point (e.g. obese patients).


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