Dandy-Walker syndrome

Abstract

A clinical analysis of 23 patients with Dandy-Walker malformation indicates that > 85% of them were diagnosed at or before 1 yr of age, and that the incidence of associated anomalies is approximately 50%, with a 17% incidence for agenesis of the corpus callosum. The significance of the presence of these anomalies is substantiated by the fact that of the 7 deaths recorded, 6 were related to this disease and 5 were affected by associated anomalies. the high mortality rate (26%) is comparable to that of other series. The differential diagnosis with posterior fossa extra-axial cysts is discussed. Ten patients were primarily treated with excision of the cyst membrane; all of them required subsequent shunting to control the intracranial pressure, demonstrating the futility of this approach. None of the patients treated with lateral ventricle shunting suffered an upward herniation of the posterior fossa contents, suggesting that combined shunting of the lateral and fourth ventricles is rarely necessary. The technical advantages of posterior fossa shunting alone are outlined. Of the 16 survivors, 14 were assessed for their mental development by means of standard psychometric testing. IQ scoring indicated that 71% of the patients have subnormal mental development (IQ < 83). There was no significant relationship between retardation and association anomalies, although agenesis of the corpus callosum was related to poor intellectual development in the 2 patients so affected (IQ of 50 and 73).