The brain and spinal cord are surrounded by three protective membranes, the outermost of which is called the dura. One function of the dura is to contain the cerebrospinal fluid (CSF)–the liquid that bathes and cushions the brain and spinal cord. A spinal fluid leak occurs when CSF escapes from the dura.
Spinal fluid leaks can occur for a variety of reasons. Some are due to a congenital defect in the dura (a defect present at birth). Some are caused by trauma that injures the dura. Other spinal fluid leaks occur for unknown reasons. These are called “spontaneous” or “idiopathic” spinal fluid leaks. Congenital and idiopathic spinal fluid leaks are most common in the cervical (upper) and thoracic (middle) spine.
A spinal fluid leak can also occur as a result of necessary medical intervention–for example, following a lumbar (lower) spine puncture procedure or a spine surgery that opens the dura. This is called a “postsurgical” CSF leak. A postsurgical CSF leak can increase the risk for infection of the spinal fluid. At the Spine Hospital at the Neurological Institute of New York, we carefully monitor patients who undergo these procedures for symptoms of spinal fluid leak.
The chief symptom of spinal fluid leak is a headache that is worse when sitting or standing, and better when lying down. This is sometimes referred to as a postural or orthostatic headache. Spinal fluid leak can also cause nausea, ringing in the ears or other change in hearing, horizontal diplopia (double vision) or other change in vision, numbness of the face, or tingling of the arms.