An abnormal collection of cerebrospinal fluid (CSF) that forms a pocket inside the cranium, just outside of the dura. Generally occurs as a complication of duraplasty (a common part of a Chiari Decompression surgery). While a small amount of fluid getting through the dura patch is normal after surgery, the body should absorb it and it should resolve within the first month or two. If it fails to reduce in size and resolve, that is a good indication that there is a cranial dura leak exists. A pseudomeningocele are most common amongst patients with an underlying connective tissue disorder (such as Ehlers-Danlos Syndromes) as their dural tissue is more fragile than that of the general population, they are more likely to have problems with the adherence of the patch, and they are more likely to have other comorbid conditions that can further complicate the healing process (such as Intracranial Hypertension, where the untreated high pressure can actually cause a cranial leak). Since the pseudomeningocele is inside the cranium, it can cause a “mass effect” that can raise intracranial pressure.

Procedure performed by a neurosurgeon in which a tub-like instrument in placed into a ventricle in order to redirect and empty cerebral spinal fluid into the abdomen, specifically the peritoneal cavity (abdominal wall).