Dr Peter G. Kranz - Interventional Neuro-Radiologist

Dr Kranz works closely alongside Dr Gray-Leithe, who is renowned for her extensive work within the field of CSF Leaks.

Ten years ago the team at Duke University Hospital began to notice an increase in the number of CSF Leak cases – they now receive a lot more referrals and have leant much over the years.

Leaks caused by needle holes usually respond very quickly to blood patches and response is that often headaches go almost instantly at patching.

Those with spontaneous leaks normally take longer and patients can experience RHP (Rebound High Pressure). Headache reduction can take hours to days to be apparent but the team normally assesses after 1 week as to whether the patch has been successful. (The patient may also still have RHP of course).

The following types of tests are performed at Duke:

• MRI - 75% show brain evidence of leak.
• They then use CT myelogram - 50% of spinal leaks will show on myelogram.
• CSF pressure is also measured when a myelogram is carried out and 30% with leaks will show below 6 on pressure test.
• Assessment / diagnosis is also made based on history and symptoms.

First thing to rule out is Rebound High Pressure. This often presents in a different position to low-pressure headaches - around the eyes/ forehead etc. It can be managed using Diamox.

However, an on going leak would also be considered.

People might have some pressure fluctuation if they were not actually leaking but have an Epidural Blood Patch.

A patient who does have a leak may experience Rebound High Pressure because over time the body goes under physiological changes to compensate i.e. not sure exactly why - but veins around spine might dilate, you start producing more spinal fluid and when leak gets shut off from patch the body might take a while to reduce the ways in which it has compensated.

They have developed certain techniques, for example, in helping to capture some faster leaks. They scan within a 1-2 mins of putting contrast in which helps capture fast/ transient leaks.

Duke also carries out a procedure to detect fast leaks or venous fistula leaks. These types of leaks have only been discovered in the past couple of years and involve the CSF escaping into a vein around the spine.

Patching is targeted using either blood or fibrin glue.

Other places have different techniques but the important thing is that the patient needs an experienced physician.

This is currently an area of active research.

At Duke, the team sees Rebound High Pressure in some form in bout 50% of those getting patched but more severe cases in about 10% - 20% of those getting patched.

After surgery it's a little less common.

Those with newly recognised venous fistula tend to get really bad High Pressure afterwards. So with that group of patients the team will try and treat PRE-surgery for RHP to prepare the body.

So, it all varies a lot. It's an area of interest - in how to prevent it, what happens to the body and what sorts of things predispose you to it. This is currently being researched.

With any patch you are at risk. If you have already had a patch and then have another while in RHP it may well push your pressure up higher. It's very important before you get another patch to work out if a patient has persistent lower pressure headaches or higher pressure headaches. They will often check pressure readings again to establish that.

But you are unlikely to have a higher chance of RHP with the 3rd patch compared to the 1st patch if starting from the same low-pressure state. But if pressure rises in between patches it would put you at higher risk.

Everyone is different and I would hesitate to put protocol on it.

CYSTS: along nerve roots exiting the spine there are frequently small diverticulum / out pouches / cysts. People without leaks often have those cysts too. Just because you have cysts doesn't mean you have a leak. But those cysts can be predisposed to leaking.

There are certain configurations of cysts and types of cysts that are more suspicious than others.

There was a time when every cyst would be patched that could be found. However lessons have been learned and how and when patching takes place is a little more selective now.

Everyone is different and would be assessed in imaging.

FIBRIN GLUE: This is a biological product; it is not necessarily better than blood, but it is different. It gets sticky faster and spreads less than blood and there are times when the location of a leak is known and so glue is better for targeted patches. Glue is always used WITH blood.

BLOOD - better when needed to spread i.e. for Blind Epidural Blood Patching or when the needle can’t be placed close to the leak site.

BLIND PATCHING
You don't need to find a leak to diagnose the condition. Some people they will have no evidence apart from symptoms.

Depending on complexity of leak etc. On average I estimate it will take 2-3 patches to get it sealed. Some people are lucky and 1 patch does it. Others patched multiple times and they have a hard time sealing the leak. Some require surgery.

The outcomes of patients being treated with an Epidural Blood Patch are being tracked now. Will have data out on that in next 6 months to a year. So better info then.

There are multiple people who can take care of leaks. Neurologist, Neuroradiologist, Neurosurgeon and Anaesthetist.

The important thing is seeing someone with experience in the condition. Often people see a neurologist first. One of pioneers is Neuro Dr Mokri at Mayo Clinic.

Duke will ask for a brain MRI with contrast before seeing a patient for spinal imaging.

Generally not. They present with different symptoms from spinal leaks. If you can picture CSF as a water tower. The pressure is greatest at the base of spine. So people with leaks lower in spine get positional headaches because that's where the pressure is greatest. But with skull base the skull is often in negative pressure upright anyway so if leak is there, headaches are usually not positional. Patients complain mostly of fluid coming out of their nose or ears or they catch meningitis. Sometimes headaches are present but they are not positional. The patients often leak more when the head is down between their knees and they experience a gush of fluid.

It can help establish baseline to access later.

For instance, a patient may be leaking but have pressure in the normal or even high range. Knowing that base pressure can help in the future if they are concerned about RHP etc. They can compare pre treatment and post treatment pressures.

When talking about 'normal values' for CSF leaks or high pressure old diagnostic criteria can be very unreliable. New research and the experience of the team at Duke shows many people who didn't fall into diagnostic criteria for leaks or high pressure do actually do have a leak/ RHP.

They are on the threshold of being able to recognise new opening pressure criteria but more research needs to be prioritised on this to help headache care in general.