The main immediate goal of treatment is the control of hydrocephalus and the enlarged posterior fossa cyst, as these can lead to increased intracranial pressure and brain damage. A minority of those affected do not develop hydrocephalus and are treated based on any associated symptoms or condition. Hydrocephalus/cyst For hydrocephalus or the posterior fossa cyst, shunts are the mainstay of treatment. However, those with DWM have a higher rate of shunt-related complications than other patients with hydrocephalus (mainly due to the unconventional anatomy). One explanation for a failure of a shunt to reduce intracranial pressure in DWM has been that the cyst may herniate into the foramen magnum and form a scarring adhesion at the cervical junction, preventing it from shrinking again. If this occurs, a suboccipital decompression with duraplasty may be attempted. In DWM, it is not agreed whether a shunt should be placed in the fourth ventricle (a cystoperitoneal shunt, or CP shunt), the lateral ventricles (a ventriculoperitoneal shunt, or VP shunt) or both, due to conflicting studies on whether the cerebral aqueduct is affected by the<unk> . However, a CP shunt almost always drains both the fourth and lateral ventricles in DWM, and according to strict definitions of the<unk> , the aqueduct should be assumed open, though imaging is important to confirm this. Many authors therefore recommend the CP shunt as the logical option. However, it is associated with a high rate of complications, including shifting and overdrainage. Overdrainage can lead to subdural haematomas, a tethered spinal cord, due to scarring, or downward herniation of the cerebral hemispheres. Spennato et al. therefore recommend a flow-regulating or anti-syphon valve. On the other hand, VP shunts have a lower rate of complications than CP shunts and are recommended initially by some. However, they are less effective in DWM, and the elevated position of the tentorium should be considered before installing a VP shunt. In patients older than 1 year, endoscopic third ventriculostomy (ETV) may be considered as the first-line treatment. This less invasive procedure creates an artificial hole in the third ventricle to allow CSF to bypass any obstruction. It cannot be used on those with brain abnormalities such as agenesis of the corpus callosum, due to the risk of CSF escaping to other brain areas. A compressed brainstem is not a contraindication, however. ETV has a more modest success rate than shunts, as the hole often closes over. It is more likely to fail in younger patients (below 1 year), and its effects on the developing brain are not yet known. Cysts posterior to the cerebellum, presenting in children younger than 5 years, have been labeled developmental retrocerebellar cysts under a new classification in relation to the proposed neuroendoscopic management. Previously, craniotomy of the posterior fossa and excision of the cystic membrane was used, which was often unsuccessful in preventing cyst reformation and carried a degree of mortality. This may still be reserved for patients with repeated shunt failures/infections. Other Treatments for any other symptoms are generally focussed on the specific condition involved and may include supported education, physical therapy or other services. Genetic counselling may be offered to parents for future conceptions.
Dandy–Walker malformation
Glial tumor
Subdural hygroma
Schizencephaly
Chiari malformation
Hemimegalencephaly
Subependymoma
Hydranencephaly