Spinal PunctureAnesthesia, SpinalSubarachnoid HemorrhagePuncturesSubarachnoid SpaceSpinal CordVasospasm, IntracranialSpinal Cord InjuriesPost-Dural Puncture HeadacheIntracranial AneurysmInjections, SpinalAneurysm, RupturedCerebral AngiographyBasilar ArterySpinal Cord DiseasesSpinal NervesSpinal CanalSpinal Nerve RootsSpinal Cord NeoplasmsNeedlesCisterna MagnaSpinal Cord CompressionTomography, X-Ray ComputedSpinal DiseasesHydrocephalusDura Mater