Improved Conspicuity of CSF-Venous Fistulas with Saline Pressure Augmentation: A Multi-Institutional Case Series

CSF-venous fistulas are a common and increasingly recognized cause of spontaneous intracranial hypotension. Most CSF-venous fistulas occur in the thoracic spine and usually arise from nerve root sleeve diverticula. Myelography in the lateral decubitus position is necessary to detect and localize these fistulas, because this technique maximizes contrast density within diverticula, thereby permitting visualization of draining veins. Many modifications to decubitus myelography have been employed in an attempt to improve the conspicuity of CSF-venous fistulas. In theory, maximizing the subarachnoid-venous pressure gradient during imaging should increase contrast flow through CSF-venous fistulas, improving detection of these sometimes-subtle leaks. Augmentation of intrathecal pressure through saline injection before myelography is a simple technique to achieve this and is common in many practices. However, only one prior case report has demonstrated the impact of pressurization on the visualization of a CSF-venous fistula. In this multi-institutional, retrospective case series, we report on a larger cohort of patients in whom CSF-venous fistulas were either occult or nondefinite on myelography without saline pressurization and subsequently definitely seen on myelography with saline pressurization. While our study design precludes determining the incremental yield of saline infusion, it nonetheless provides further support for the value of saline pressurization during myelography in patients with suspected CSF-venous fistulas.