What is the treatment for Dandy-Walker syndrome?

Treatment of Dandy-Walker Syndrome

Combined ventriculocystoperitoneal shunting (simultaneous shunting of both the lateral ventricles and posterior fossa cyst) is the most effective initial surgical approach for Dandy-Walker syndrome with hydrocephalus, achieving symptom control in 92% of cases and minimizing the need for subsequent revision procedures. 1

Initial Diagnostic Evaluation

When Dandy-Walker syndrome is suspected, obtain MRI imaging to confirm the diagnosis and assess for critical anatomical features:

• Document the presence and degree of cerebellar vermian hypoplasia (present in 88% of cases) 2
• Evaluate for aqueductal patency versus stenosis, as this determines optimal surgical approach 3
• Identify associated CNS anomalies including corpus callosum agenesis, occipital encephalocele, or polymicrogyria (present in 22-48% of cases) 2, 1
• Assess both lateral ventricle and posterior fossa cyst size to guide shunt planning 3

Primary Surgical Management

First-Line Treatment: Combined Shunting

Place simultaneous ventriculoperitoneal and cystoperitoneal shunts as the initial procedure for patients presenting with hydrocephalus (which occurs in 91-94% of cases at diagnosis). 1, 4 This approach:

• Achieves successful hydrocephalus control in 92% of patients 1
• Requires fewer revision procedures compared to single shunt systems 2, 1
• Prevents the development of isolated fourth ventricle syndrome that occurs in 43% of patients treated with VP shunt alone 4

Alternative Approaches Based on Anatomy

Consider endoscopic third ventriculostomy (ETV) with or without cyst fenestration in select cases, particularly when preoperative MRI demonstrates aqueductal patency. 3 This approach:

• May avoid permanent shunt dependency in successful cases 3
• Requires placement of an aqueductal stent from the third ventricle to the posterior fossa cyst if aqueductal stenosis is present 3
• Has a failure rate requiring subsequent VP shunt placement in approximately 24% of cases (5 of 21 patients) 3

Cyst membrane fenestration alone can be considered in highly selected cases but typically requires existing or subsequent ventricular shunting. 2

Management of Treatment Failures

Common Pitfalls and Revision Strategies

If VP shunt alone was initially placed, monitor closely for development of isolated fourth ventricle (occurs in 27-43% of cases), which manifests as:

• Reappearance or enlargement of posterior fossa cyst despite controlled ventricular size 2, 4
• New posterior fossa symptoms including ataxia, cranial nerve deficits, or brainstem compression 1
• Add cystoperitoneal shunt when isolated fourth ventricle develops 2, 4

If CP shunt alone was initially placed (not recommended as first-line), expect need for additional VP shunt in 86% of cases (6 of 7 patients) due to persistent ventricular dilatation. 2

Long-Term Monitoring

• 96% of survivors remain shunt-dependent long-term, requiring lifelong surveillance for shunt malfunction 1
• Monitor developmental progress, as one-third of children demonstrate developmental delay at presentation 1
• Screen for shunt complications including infection, obstruction, and over-drainage 5, 2

Important Clinical Considerations

Avoid posterior fossa craniectomy with membrane excision as primary treatment, as this historical approach has been superseded by shunting procedures with superior outcomes. 1, 4

Recognize that 70% of patients become symptomatic within the first year of life, presenting primarily with signs of hydrocephalus (macrocephaly, bulging fontanelle, developmental delay) rather than focal neurological deficits. 1

The presence of associated anomalies does not contraindicate surgical treatment but may impact overall developmental prognosis. 2, 1