If there is a tear in the dura mater, the membrane surrounding the brain and spinal cord, the cerebrospinal fluid leaks out. Many of the resulting symptoms overlap with those of SCDS. Sometimes this condition, known as a CSF leak, is concomitant with SCDS, and must be addressed simultaneously during surgery. CSF leaks from the spinal region differ from cranial leaks in their manifestation and require a different form of treatment. SCDS patients have a much higher incidence of other skull base defects and probably have a higher incidence of spontaneous cranial CSF leaks and encephaloceles. The latter are sac-like protrusions or projections of the brain, and the membranes that cover it, through openings in the skull.