Cerebrospinal fluid fistulas consist of the leakage of the fluid enveloping the central nervous system (cerebrospinal fluid [CSF]) usually through the nose, resulting in an incessant, totally clear, watery fluid drip that increases with exertion and in certain postures.
It differs from nasal mucus in being more transparent, less viscous, increasing with exertion and completely soaking the tissues.
Why does it occur?
CSF leakage is caused by a fracture at the base of the skull. The main causes of CSF fistulas are trauma, and it should be noted that CSF fistulas can occur even with low-energy trauma.
The second cause of CSF fistulas are previous surgeries, especially nasal surgeries, or deep nasal manipulations.
What are the risks of fistulas?
In addition to the discomfort of the constant outflow of fluid through the nose, they often cause headaches that can become very intense and increase with exertion. The headache is due to the loss of pressure within the central nervous system and is a symptom of seriousness.
The most feared complication is infection. The same point of fracture at the base of the skull that produces the fistula is a point of entry into the central nervous system for bacteria that are under normal conditions in the nose of people. If an infection occurs, it is meningitis, a very serious infection which, if not treated in time, can even become life-threatening.
What kind of treatment should be followed?
The first step is to consult an expert if CSF fistula is suspected. An accurate diagnosis of the fistula should be made and it should be confirmed that it is a CSF leak. If there are doubts with macroscopic features, analytical tests are performed to confirm that it is cerebrospinal fluid.
A brain MRI and cranial CT scan should then be performed to locate the skull base fracture as precisely as possible and to rule out the presence of herniation of the cranial contents due to the fracture, which sometimes occurs.
What type of treatment should be followed?
Fistulas should be treated by experienced professionals, as their effective treatment is sometimes difficult. Most fistulas can be treated by minimally invasive endoscopic surgical techniques.
A small 4mm camera (endoscope) is introduced through the nose, and after locating the point of bone fracture, it is sealed using mucosa from the patient’s own nose. If there is herniation of cranial content due to the fracture, sometimes an endoscopic repair can also be performed through the nose, depending on the surgeon’s experience with this type of technique.
In case of complex CSF fistulas, either because they occur in patients with complex skull fractures, or because they are recurrent or persistent fistulas for a long time, or because they are associated with herniations of cranial material, they must be repaired by means of a craniotomy. A cranial incision is made, an opening is made in a frontal area of the skull (craniotomy) and the fracture site is surgically accessed and repaired.
Treatment results
Treatment by an experienced team has a high success rate, both in endoscopic treatment and in open surgery. Once the CSF fistula is resolved, the runny nose, headache and risk of infection disappear.