Ventricular septa in the neonatal age group: diagnosis and considerations of etiology.

Twenty-four patients with ventricular septa are discussed. Seventeen patients had septa acquired during the neonatal period and seven exhibited septations at birth (cogenital septa). Among the acquired septa, there were true intraventricular septa and septa that originated outside the ventricles but later became part of the ventricular system (pseudosepta). Pseudosepta originate in necrotic, cavitating periventricular white matter that, in temporal sequence, becomes ventricularized. Serial use of cranial sonography provided important information about the pathologic mechanisms that govern the development of septa. Intraventricular hemorrhage and infection are the major causes of true intraventricular septa, while periventricular leukomalacia serves as primary cause of pseudosepta. Sonography is the diagnostic method of choice. Septa are associated with a high incidence (62%) of shunt failure.