Cerebrospinal fluid–venous fistula is an increasingly recognized cause of spontaneous intracranial hypotension.[1][1] The site of the leak is between the dural sleeve around a spinal nerve root and the surrounding foraminal veins. In appropriately investigated patients, transvenous embolization of the draining foraminal and paraspinal veins has been shown to be an effective way of treating the disease, with low periprocedural morbidity, improvement in symptoms and radiological appearances.[2][2] [Video 1][3] shows the technique employed in a typical case using Onyx (Medtronic, Minnesota, USA) to embolize a CSF–venous fistula at the right T10 neural foramen. Video 1 Video showing the technique for trans-venous embolization of a right T10 CSF-venous fistula for the treatment of spontaneous intracranial hypotension. The first section covers patient selection and work up, before then focusing on the technical aspects of navigating through the azygos system to the target foramen and completely occluding the pathway for CSF outflow. [1]: #ref-1 [2]: #ref-2 [3]: #F1