A conceptual model of pseudo–meningeal lumen formation in cerebrospinal fluid–venous fistula

Abstract

Cerebrospinal fluid–venous fistula (CVF) is an increasingly recognized cause of spontaneous intracranial hypotension (SIH), particularly in patients without evident epidural cerebrospinal fluid (CSF) collections. Although CVF is widely regarded as a clinically actionable imaging phenotype, its underlying structural basis and pathophysiological mechanism remain incompletely understood.

We conducted a narrative review of the literature published since the initial description of CVF, focusing on imaging characteristics, surgical and pathological observations, therapeutic outcomes, and longitudinal clinical courses. Across studies, several recurring features—including the relative absence of venous reflux, selective drainage pathways, and temporal variability in detectability—suggest that a single fixed-fistula model may not fully account for the diversity of reported findings.

To integrate these observations, we propose a conceptual framework in which CVF is interpreted as a disease phenotype that may emerge during the chronic course of spinal CSF leakage. Central to this framework is the concept of a pseudo–meningeal lumen, defined as a semi-stabilized CSF transit pathway formed through sustained leakage and associated tissue remodeling. When this pathway becomes preferentially expressed as venous-dominant drainage, it may be visualized on imaging as a CVF phenotype.

This time-dependent framework may provide a coherent basis for integrating previously reported findings and support a more dynamic interpretation of CVF in both diagnostic and therapeutic contexts.