The natural history of Dandy-Walker syndrome in the United States: A population-based analysis

BACKGROUND: Dandy-Walker syndrome (DWS) is a congenital disorder typically manifesting with hydrocephalus. The classic anatomic hallmarks of DWS are hypoplasia of the cerebellar vermis, anterior-posterior enlargement of the posterior fossa, upward displacement of the torcula and transverse sinuses, and cystic dilatation of the fourth ventricle. AIMS: Although optimal treatment of DWS typically requires neurosurgical intervention to prevent intracranial pressure increases incompatible with life, the natural history of this disorder has yet to be evaluated on a nationwide level. SETTINGS AND DESIGN/MATERIALS AND METHODS: The Kids’ Inpatient Database covering 1997-2003 was used for analysis. Children younger than age 18 admitted for DWS (ICD-9-CM = 742.3) were analyzed with a matched control group. The primary procedure codes for operative CSF drainage were coded into the analysis. The incidence of DWS was 0.136%; 14,599 DWS patients were included. STATISTICAL ANALYSIS USED: Multiple logistic regression models were used. Odds ratios (OR) were reported with 95% confidence intervals. RESULTS AND CONCLUSIONS: Mortality (OR = 10.02; P < 0.0001) and adverse discharge disposition (OR = 4.59; P < 0.0001) were significantly greater in DWS patients compared with controls. 20.4% of DWS patients received operative cerebrospinal fluid (CSF) drainage, 81-times more than controls (P < 0.0001). CSF drainage reduced mortality by 44% among DWS patients (P < 0.0001). Although DWS is associated with a 10-fold increase in mortality, operative CSF drainage nearly halves the mortality rate. Based on these findings (Class IIB evidence), it is likely that the increased mortality associated with DWS is directly attributable to the nearly 80% of DWS patients who did not receive operative CSF drainage for hydrocephalus. Consequently, increased access to neurosurgical intervention could reduce the mortality rate of DWS towards that of the general population.