Congenital deformities of the brain and meninges
Arachnoid cyst
Arachnoid cysts are collections of cerebrospinal fluid (liquor) between the soft meninges, the so-called arachnoid leaves, so that a cyst may develop. This cyst may freely communicate with the surrounding liquor-filled areas, on the one hand, but, on the other hand, may have a expansive effect. Thus, the arachnoid cyst may impose pressure on the neighbouring brain and even lead to an obstruction of the normal circulation of the cerebrospinal fluid. This causes symptoms such as epilepsy, head aches, hydrocephalus.
In case of such symptomatic arachnoid cysts, surgical treatment is necessary. Today, the endoscopic fenestration of the cyst to the normal ventricles is the preferred method, depending on the topographic situation, i.e. the localisation of the arachnoid cyst. In some cases, however, a microscopic open surgery or the implantation of an internal drainage system is necessary.
Temporal subarachnoid cyst (left), supra cellular arachnoid cyst (center) and arachnoid cyst on the brain surface (right)
Deeply located cerebellar tonsils with Chiari malformation type I
Chiari malformation
Chiari malformation is a deformity of the posterior fossa which is all in all too small. The Tentorium cerebelli stands steeply, and the cerebellar tonsils reach too deeply into the spinal canal (Chiari type I). A more complex form (Chiari type II) is encountered in association with a meningomyelocele.
A cave formation in the spinal cord filled with cerebrospinal fluid, the so-called syringomyelia, as well as an expansion of the ventricular system with intracranial pressure increase (hydrocephalus) may occur and also may result in neurological symptoms.
Dandy Walker malformation
The Dandy Walker malformation presents a developmental disorder with hypoplasia (dysplasia) of the cerebellar vermis and of the medial aspects of the cerebellar hemispheres. The fourth ventricle impresses here as a huge cyst. The Dandy Walker malformation often occurs together with a hydrocephalus. Also other abnormalities may occur collaterally, such as corpus callosum.
Dr. Mukesch Shah, MD
Senior neurosurgeon
Children consultation hours
Dr. Florian Volz, MD
Attending neurosurgeon