Non‐Invasive Intracranial Pressure Waveform Assessment as a Screening Test for Abnormal Lumbar Puncture Results

Abstract

ABSTRACT Background Lumbar puncture (LP) is essential for detecting intracranial hypertension (IH) but is often non‐diagnostic and not without complications. A skull extensometer‐based non‐invasive intracranial pressure waveform assessment (NIWA) has shown promise in detecting IH in neurocritical settings. This study investigated its feasibility and accuracy among outpatient neurological individuals. Methods This cross‐sectional study enrolled adults referred to routine outpatient LP at a tertiary‐care hospital. Subjects underwent baseline supine NIWA, then were sequentially divided (2:1:1 ratio) to: LP then follow‐up supine NIWA; follow‐up NIWA while sitting then LP; or follow‐up NIWA during Valsalva maneuver then LP. Several waveform parameters and their variation between baseline and follow‐up assessments were compared with LP results. IH was defined as LP opening pressure > 25cmH2O. Results The study included 130 subjects, and 28 (21.5%) presented with IH. Dicrotic peak slope < 0.143 predicted IH with 89.5% sensitivity and 29.7% specificity (AUROC = 0.680, 95% CI 0.541–0.819). Equations derived from multivariate logistic regression models including mostly latency‐related parameters of the entire waveform and its percussion and dicrotic peaks predicted cerebrospinal fluid (CSF) chemocytology changes with AUROC = 0.661 (95% CI 0.542–0.780) and overall abnormal LP results (IH and/or altered CSF chemocytology) with 96.2% sensitivity and 24.1% specificity (AUROC = 0.696, 95% CI 0.572–0.820). Parameter changes after LP, during Valsalva maneuver, and sitting position did not improve diagnostic accuracy. Conclusions NIWA was feasible and detected IH and CSF changes with high sensitivity among real‐world neurological outpatients. While LP remains pivotal to many cases, pre‐LP screening with NIWA may enhance diagnostic yield and mitigate complications and healthcare‐related costs.