Did hydrocephalus do lumbar puncture needle pumping how can not pump water

Hello, hydrocephalus is the formation of cerebrospinal fluid circulation disorder, or cerebrospinal fluid secretion and less absorption. Under normal circumstances, CSF can be released by lumbar puncture, but hydrocephalus cannot be extracted by lumbar puncture in the case of fourth ventricle obstruction. The main reason why hydrocephalus doesn't drain is obstruction or low pressure.