Lumbar puncture position influences intracranial pressure

Pedersen SH, Andresen M, Lilja-Cyron A, Petersen LG & Juhler M


The standard lumbar puncture position involves maximum flexion of both lumbar and cervical spine. The cerebrospinal fluid opening pressure (CSFop) is measured in a horizontal position. This study investigated if flexion of hip and neck both separately and simultaneously influence intracranial pressure (ICP) to a clinically relevant extent.


Thirty-nine patients, undergoing invasive ICP monitoring as part of diagnostic work-up, were included. The patients underwent either a vertical postural examination (n = 24) or a horizontal postural examination (n = 15) to examine a varying degree of spine flexion.


The vertical examination showed that ICP decreased by 15.2 mmHg when straightening the neck in a sitting lumbar puncture position (n = 24, IQR –20.1 to –9.7). In the horizontal examination, ICP increased in all but one patient when changing from supine position to lateral recumbent position (n = 15, median increase of 6.9 mmHg, IQR 3.1 to 9.9). Straightening the hips alone decreased ICP with 0.2 mmHg (n = 15, IQR –0.5 to 2.0), while straightening the neck alone decreased ICP by 4.0 mmHg (n = 15, IQR –5.9 to –1.7). However, when straightening the hip and neck simultaneously ICP decreased by 6.4 mmHg (n = 6, IQR –9.5 to –4.4).


Neck flexion alone, and neck flexion and hip flexion in combination, has significant confounding influence on ICP. This may cause patients to shift from a normal ICP range to a pathological ICP range, which will potentially affect treatment decisions. Consensus on guidelines for body position including neck and hip flexion measuring CSFop may be needed.

Read the full paper in Acta Neurochir (click here).