A premature infant, born at 29 weeks gestation, suffers a significant intraventricular hemorrhage that extends into the subarachnoid space. Over the next few weeks, the infant develops progressive hydrocephalus. The obstruction to cerebrospinal fluid (CSF) flow is determined to be at the level of the basal cisterns and arachnoid villi, secondary to inflammation and fibrosis from the blood products. How is this type of hydrocephalus best classified?