My wife is suffering from a sphenoid sinus defect with cerebrospinal fluid leak. Spinal fluid is leaking through her left nostril. The leak occurs when she is fatigued or catches a cold, and she has had early-stage bacterial meningitis during these encounters. She has had an operation to stop the leak, but it has started again. Are there any strategies other than surgery to stop the leak? Is there a chance that the leak will stop on its own? Can an operation really solve the problem?

G.D.

First, a bit of anatomy for readers who may not understand your question:
The sphenoid sinus is an "air pocket" in the bone of the base of the skull. It is located above and behind the nasal cavities, and it is also behind the eyes. If you wanted to poke yourself in the sphenoid sinus with a Q-tip, the Q-tip would have to be about 4 inches (10cm) long.

The brain and spinal cord are bathed in a liquid called "cerebrospinal fluid," commonly abbreviated CSF. The brain and spinal cord are wrapped in a thin membrane called the pia mater (Latin for "tender mother"), and an outer, more dense membrane called the dura mater ("tough mother"). CSF is contained between the pia mater and dura mater. These membranes are known, collectively, as the meninges. Infection of these membranes is meningitis.

Under normal circumstances, in order to develop a CSF leak into the sphenoid sinus, one would have to have defects in the bone of the roof of the sphenoid sinus, and in the dura mater immediately above this roof. Two possible causes of such a defect would be head trauma or another form of trauma -- surgery (for example, sinus surgery or surgery on the pituitary gland). It is also possible that your wife was born with a thin or absent section of bone at the roof of the sphenoid sinus. Over the years, dura mater may have ballooned into the sinus, then became thinner and thinner until it "blew out," much as a tire might blow out from a focal weakness of the inner tube's rubber.

The danger of a CSF leak lies not in the leak itself, which is often just annoying. The danger lies in the possible development of an intracranial infection -- most commonly, meningitis. (If CSF can leak out, then it is quite possible that bacteria within the nasal cavity can travel upwards, leading to infection.) A severe case of bacterial meningitis can result in blindness, deafness or even death.

How can a CSF leak be stopped? There are three basic strategies. If the leak is relatively new (for example, a leak noticed within a day or two of sinus surgery), it may stop with conservative management. Bed rest with the head of the bed elevated and placement of a lumbar drain are the basic elements of conservative management. (A lumbar drain is a small, flexible tube placed into the spinal canal in the lower back. It drains CSF in order to decrease the pressure of CSF within the central nervous system.)

The other two strategies are both surgical. If the hole is not too large, it can be patched endoscopically. In other words, your wife's surgeon would use a flexible fiberoptic scope to obtain a magnified view of the interior of the sphenoid sinus, and would then take steps to plug the leak from below. My guess is that this is the operation your wife had previously. The advantage of this technique is that it is minimally invasive. The disadvantage is that it may not work very well if the leak is extensive.

The second surgical strategy requires a procedure called a craniotomy. A neurosurgeon would open the skull and patch the leak from above. This is not exactly brain surgery -- call it "near-brain surgery." It is a more invasive approach than the endoscopic approach, but it may be the only successful approach for large leaks.

Will the leak heal spontaneously? If she has had this problem for a long time (longer than a few weeks), then I am pessimistic that this will somehow cure itself. Given the risks of bacterial meningitis, I would be extremely reluctant to adopt a "wait-and-see" approach.

Do the operations work? Yes! As with any operation, the chance of success depends upon the severity of the problem and the experience of the surgeon. It would be very reasonable to question your wife's doctor on both of these points.