The interventional procedures advisory committee considered evidence on transvenous embolisation for spontaneous intracranial hypotension caused by a cerebrospinal fluid (CSF)–venous fistula from several sources. This included evidence submitted by 1 company, Medtronic, along with a review of efficacy and safety evidence and responses from stakeholders. Full details are available in the project documents for this guidance.
NICE did a rapid review of the literature on the efficacy and safety of this procedure. The evidence included 1 systematic review and meta-analysis and 7 observational studies. It is presented in the summary of key evidence section in the interventional procedures assessment report.
A 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. CSF–venous fistula was first described and recognised as a cause of spontaneous intracranial hypotension in 2014.
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 injection, surgical ligation or transvenous embolisation.
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. Transvenous embolisation 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.
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 surgery.
The professional experts and the committee considered the key efficacy outcomes to be:
symptom resolution including headache resolution
technical success of the procedure
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
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 impacting people's quality of life. 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.
Current treatment options for spontaneous intracranial hypotension caused by CSF–venous fistula are limited. Using transvenous embolisation while further evidence is generated would provide people with an additional treatment option alongside surgical repair (which is more invasive) and CT-guided fibrin glue injection (which is currently off label for this indication). People with the condition may benefit from the availability of all 3 treatment options. They should be fully informed about each option, including the potential benefits and risks.
While transvenous embolisation is an emerging treatment for spontaneous intracranial hypotension caused by CSF–venous fistula, the material used in the procedure to seal the leak is widely used in other endovascular procedures. Healthcare professionals have used it for a long time, so they understand how to handle it and its safety profile. So, this procedure is an incremental adaptation of an existing technique to address a specific condition, and it is still evolving.
This procedure is usually done by interventional radiologists. The procedure requires involvement of a multidisciplinary team in patient selection and follow-up. Healthcare professionals with neurology or neurosurgery expertise need to be part of the multidisciplinary team in the immediate post-procedure follow-up period. This is in case of rebound intracranial hypertension requiring a lumbar puncture or drain, although this can usually be managed with medicines in most cases.
Current evidence is limited and comes from single-centre studies, although the results appear consistent. The additional data on the procedure provided at consultation gives incremental support to the evidence base on efficacy but does not fulfil the evidence gaps.
There is a need for data on long-term outcomes on both efficacy and safety, and to understand which patients benefit most from the procedure. It is also important to generate comparative data between different treatment options. While the committee acknowledges that randomised controlled trials may be challenging to conduct, they remain the gold standard and should be done where feasible.
Data should be collected in an appropriate registry that meets NICE registry standards. The data must be accessible to the NHS.
The procedure is only offered in 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.