Epidural SpaceAnesthesia, EpiduralNeedlesInjections, EpiduralInjectionsDura MaterSpinal CanalLigamentum FlavumAnalgesia, EpiduralLumbosacral RegionEpidural NeoplasmsRadiculopathyLipomatosisSpinal Nerve RootsLumbar VertebraeCoccyxAnalgesia, ObstetricalInjections, SpinalThoracic VertebraeSpinal DiseasesMyelographyTissue AdhesionsAnesthesia, ObstetricalFiber Optic TechnologyAnesthetics, LocalSpinal CordMathematical ConceptsIntracranial HypotensionFluoroscopyLaminectomyIntervertebral Disc DisplacementSpinal Cord CompressionBlood Patch, EpiduralEpidural AbscessSpinal NeoplasmsAnesthesia, CaudalAnatomy, Cross-SectionalCatheterizationFentanylBupivacaineInjections, IntravenousInjections, IntramuscularLidocaineCervical VertebraeTomography, X-Ray ComputedEndoscopyMagnetic Resonance ImagingSpinal Cord DiseasesSpinal StenosisLow Back PainSteroidsNerve BlockInjections, IntralesionalInjections, SubcutaneousInjections, Intra-ArticularPregnancy Trimester, Third