Epidural SpaceAnalgesiaAnalgesia, EpiduralAnalgesia, ObstetricalAnesthesia, EpiduralNeedlesInjections, EpiduralAnalgesia, Patient-ControlledDura MaterSpinal CanalLigamentum FlavumAnesthetics, LocalLumbosacral RegionBupivacaineAnalgesics, OpioidFentanylPain, PostoperativeAnesthesia, ObstetricalEpidural NeoplasmsInjections, SpinalMorphinePain MeasurementLipomatosisSpinal Nerve RootsRadiculopathyLumbar VertebraeCoccyxAnesthesia, CaudalNerve BlockThoracic VertebraeSpinal CordAcupuncture AnalgesiaSpinal DiseasesMyelographyTissue AdhesionsFiber Optic TechnologyAnalgesicsLaminectomyMathematical ConceptsIntracranial HypotensionLidocaineIntervertebral Disc DisplacementEpidural AbscessSpinal Cord CompressionFluoroscopyBlood Patch, EpiduralCatheterizationSpinal NeoplasmsMeperidineAnatomy, Cross-SectionalLabor PainPainSufentanilCervical VertebraeTomography, X-Ray ComputedEndoscopyLabor, ObstetricSpinal Cord DiseasesMagnetic Resonance ImagingLow Back PainSpinal StenosisPregnancyAmidesAnesthesia, SpinalSteroidsTramadolDouble-Blind MethodPregnancy Trimester, ThirdProspective StudiesAnalgesics, Non-Narcotic