Lumbar Puncture Opening Pressure and Continuous Intracranial Pressure Monitoring: Concordance and Clinical Implications in Idiopathic Intracranial Hypertension.

BACKGROUND AND

OBJECTIVES

Lumbar puncture (LP) remains a standard diagnostic tool for assessing intracranial pressure (ICP) in idiopathic intracranial hypertension (IIH), yet it provides only a single static measurement that may not reflect dynamic pressure fluctuations. Although continuous ICP monitoring (ICPm) offers real-time assessment of postural and circadian variability, the relationship between LP and ICPm measurements done after nondiagnostic LP remains unclear.

METHODS

We retrospectively reviewed adult patients with IIH at a single center (2016-2023) who underwent ICPm within 9 months of an LP without intervening therapies affecting ICP. Continuous ICPm recordings were analyzed across postures and tilt angles and compared with LP opening pressures using Spearman correlation, Bland-Altman analysis, and categorical concordance of normal, high-, and low-pressure classifications.

RESULTS

Eighty-one patients met inclusion criteria (mean age 38.1 ± 11.8 years, 87.7% female, mean body mass index 34.7 ± 8.8 kg/m 2 ). LP identified elevated pressure in 32 (39.5%) patients, while m categorized 10 (12.3%) as high, 18 (22.2%) as low, 8 (9.9%) as mixed, and 45 (55.6%) as normal. LP and ICPm values demonstrated only moderate correlation (ρ = 0.37-0.51, P ≤ .014) with a consistent negative bias, as LP pressures were 10 to 27 mm Hg higher than observed for ICPm. Discordance was notable in patients with low or mixed ICP profiles, in whom LP frequently yielded normal or elevated readings.

CONCLUSION

LP and continuous ICPm are not interchangeable, as LP systematically overestimates parenchymal ICP and fails to capture postural and circadian variability. While LP remains useful for initial diagnosis, continuous ICPm provides a more comprehensive physiological assessment and may better guide management in IIH patients with persistent or ambiguous symptoms.