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

A cerebrospinal fluid (CSF)–venous fistula is an abnormal connection between the CSF space surrounding the brain and spinal cord, and the venous system. This abnormal connection allows CSF to leak into the venous system, causing spontaneous low pressure in the brain, a condition called spontaneous intracranial hypotension.

Spontaneous intracranial hypotension can present with a variety of symptoms. These include orthostatic headache, which typically worsens upon standing and gets better when lying down; neck stiffness; nausea; vomiting; vertigo; tinnitus; visual disturbances; dizziness and imbalance.

Initial management may include bed rest, hydration, and oral or intravenous caffeine. If symptoms persist then non-targeted epidural blood patching may be offered. If this fails, advanced imaging such as digital subtraction myelography or dynamic CT myelography is done to locate the CSF–venous fistula. Once the fistula is located, targeted treatments are considered. These may include CT-guided fibrin glue injections, which are usually done as a day-case procedure under local anaesthesia and may be offered immediately after the scan, or surgical ligation.

Existing treatment options may not always be feasible or suitable. When a fistula is located near an eloquent or functional nerve root, surgery may not be the best option. This is because it can damage nerves and cause muscle weakness in the arms and legs. Existing treatments can also fail, risking recurrence or the development of new CSF–venous fistulas. Transvenous embolisation offers an alternative treatment option. It could be particularly useful when nerve root ligation cannot be done, when people are unfit for or decline surgery, or when there is treatment failure or recurrence after a CT-guided fibrin glue injection. Although the procedure is more invasive than CT-guided fibrin glue injection, it is less invasive than surgery and may reduce hospital length of stay and overall patient risk.

Transvenous embolisation adapts established endovascular techniques for treating spontaneous intracranial hypotension caused by a CSF–venous fistula. By accessing and occluding the fistula within the venous system, it provides a less invasive targeted alternative to existing treatments.

The professional experts and the committee considered the key efficacy outcomes to be: symptom resolution, headache resolution, success rate and long-term durability of repair.

The professional experts and the committee considered the key safety outcomes to be: post-treatment rebound intracranial hypertension or rebound headache, pain, persistent leak, inadvertent embolisation (movement of embolic agent), failure of procedure and need for retreatment.

Fifteen commentaries from people who have had this procedure were discussed by the committee.

Spontaneous intracranial hypotension caused by a CSF–venous fistula is a debilitating condition. Its diagnosis is often complex and delayed. The diagnosis needs myelography which is invasive, difficult to interpret and needs expert evaluation. People may have more than one fistula. If the leak can be stopped, it can dramatically improve quality of life.

There are several treatment options for spontaneous intracranial hypotension caused by a CSF–venous fistula. These include surgery, CT-guided fibrin glue injections and transvenous embolisation. Surgery may have a lower recurrence rate, but it may not be suitable for people with multiple fistulas. CT-guided fibrin glue injection is less invasive and is typically done under local anaesthesia. Whereas transvenous embolisation is usually done under general anaesthesia.

Transvenous embolisation for spontaneous intracranial hypotension caused by a CSF–venous fistula is a highly specialised procedure. It is done in a limited number of specialist centres by healthcare professionals with specific training and experience in the procedure. The procedure is evolving as centres adapt it to meet the needs of their patients.

Current evidence is limited and comes from single-centre studies, although the results appear consistent. There are no major safety concerns. It is not known how well these findings translate to real-world practice. Given the availability of alternative treatment options, comparative randomised controlled trials should be done to better assess the efficacy and safety of the procedure.

The patient population is not homogenous, with some people experiencing recurrent fistulas despite treatment, and other people having resolution of their fistula with treatment. Transvenous embolisation could be a useful option for people with spontaneous intracranial hypotension caused by a CSF–venous fistula when other treatment options have failed.

Digital subtraction myelography or dynamic CT myelography is essential for precise targeting of the fistula. This is because closure cannot be directly confirmed during the transvenous embolisation procedure.

The procedure is offered in a limited number of specialist centres in the UK. This may create challenges in accessibility and geographic equity. Delays in diagnosis and treatment may also further widen disparities in care.