Transvenous embolisation for spontaneous intracranial hypotension caused by a cerebrospinal fluid–venous fistula

Transvenous embolisation is typically done under general anaesthesia but can also be done under local anaesthesia or conscious sedation. Venous access is achieved through the common femoral or internal jugular vein. A guiding catheter is navigated into the superior vena cava and then into the azygos vein or other relevant venous drainage pathway. Alternative pathways can include the hemiazygos vein, ascending lumbar veins or vertebral veins depending on the location of the fistula. A hydrophilic or stiff wire is often needed for access. Once the catheter has reached the appropriate venous system, a microcatheter is advanced over a fine wire to selectively catheterise the foraminal or paraspinal vein that contains the fistula.

Venography is done to confirm the location of the fistula and see the venous drainage pattern. Venography is an imaging technique that uses contrast dye to visualise the veins under X-ray. The fistula is then embolised using a liquid embolic agent. A high-viscosity formulation is injected to create a proximal plug and then a low-viscosity formulation is injected which flows across the fistula or fistulous network.

The success of the procedure is judged by clinical follow-up and imaging follow-up with MRI. A post-procedure CT myelogram or digital subtraction myelography may be done to assess the distribution of the embolic agent and the extent to which the fistula has sealed. But, this is not done routinely for this purpose, because it is invasive.