Endoscopic Repair of a Cerebrospinal Fluid Leak

Cerebrospinal fluid, or CSF, is the fluid inside the brain and the spinal cord and between the membranes that wrap them. The outermost and strongest of those membranes is the dura. When the dura is damaged, the fluid leaks out. That is called a CSF leak or a CSF fistula. When the leak runs into the nose and the sinuses around it, clear fluid drips from the nose, and that is called rhinorrhoea.

Clear fluid that runs from one nostril, and increases when you bend forward or strain, raises the possibility of a CSF leak. Think of it in every patient, and especially in anyone who has had a head injury or an operation on the nose or the sinuses.

The nose and the sinuses are not sterile. If the microorganisms there pass through the damaged area into the membranes of the brain, they cause very serious complications. Meningitis is inflammation of the brain membranes. Encephalitis is inflammation of the brain tissue. An abscess can also form inside the brain.

What causes a leak

• Injury during surgery near the dura, most often endoscopic sinus surgery
• Tumours next to the dura, usually malignant ones
• Fractures of the dura and the bone next to it, after a blow to the face or head
• Weak points, openings and anatomical variations in the bone around the dura, present from birth

Leaks also happen with no cause that can be found. Those are called spontaneous.

Making the diagnosis

Laboratory analysis of the clear fluid from the nose confirms the diagnosis. After that the leak has to be located before treatment can be planned. Computed tomography and MRI come first. If standard imaging cannot show the site, a special dye is put into the cerebrospinal fluid and the nose is examined with an endoscope.

The repair

To stop the leak, the damage in the dura has to be repaired so that it is watertight.

The endoscopic method repairs leaks in every anatomical area next to the nose and the sinuses. That runs from the frontal sinus at the front to the sphenoid sinus at the back. Success rates reach 95 to 97 per cent.

During the operation the surgeon views the damaged area through endoscopes inside the nose. The repair uses small pieces of tissue, usually taken from the patient’s own nose or body: fat, cartilage, a thin plate of bone, or fascia. Special tissue glues are used when they are needed. The repair is done without serious extra damage outside the area treated.

Compared with the open approach from outside, the endoscopic method reaches similar success rates with less tissue injury, a shorter healing time and a more comfortable recovery.