Epidural SpaceHematomaHematoma, Epidural, CranialHematoma, SubduralHematoma, Subdural, ChronicAnesthesia, EpiduralHematoma, Subdural, AcuteNeedlesHematoma, Epidural, SpinalDura MaterInjections, EpiduralHematoma, Subdural, IntracranialLigamentum FlavumSpinal CanalAnalgesia, EpiduralLumbosacral RegionEpidural NeoplasmsHematoma, Subdural, SpinalTomography, X-Ray ComputedRadiculopathyLipomatosisLumbar VertebraeCoccyxSpinal Nerve RootsLaminectomyAnalgesia, ObstetricalMyelographyThoracic VertebraeSpinal DiseasesSpinal Cord CompressionIntracranial HypotensionCerebral HemorrhageTrephiningTissue AdhesionsFiber Optic TechnologyAnesthesia, ObstetricalBlood Patch, EpiduralSpinal CordMathematical ConceptsIntervertebral Disc DisplacementEpidural AbscessMagnetic Resonance ImagingFluoroscopyAnesthetics, LocalSpinal NeoplasmsInjections, SpinalAnesthesia, CaudalCatheterizationAnatomy, Cross-SectionalCervical VertebraeCraniotomyFentanylSpinal Cord DiseasesEndoscopyBupivacaineSpinal StenosisSubdural SpaceLow Back PainLidocaineTreatment OutcomeSkull FracturesNerve BlockSteroidsPregnancy Trimester, ThirdCerebral Hemorrhage, Traumatic