title: The difference between nothing and one.
mesh_terms: D000328:Adult; D002557:Cerebrospinal Fluid Shunts; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000601:surgery*; D006850:Hydrocephalus, Normal Pressure / Q000601:surgery; D008297:Male; D008875:Middle Aged