AnalgesiaAnalgesia, EpiduralSpinal CordAnalgesia, ObstetricalAnalgesia, Patient-ControlledSpinal Cord InjuriesInjectionsAnalgesics, OpioidInjections, SpinalPain, PostoperativePain MeasurementMorphineAnesthesia, SpinalBupivacaineAnesthetics, LocalAnalgesicsFentanylAcupuncture AnalgesiaPainSpinal NervesAnesthesia, EpiduralSpinal Cord DiseasesSpinal Nerve RootsInjections, IntravenousInjections, IntramuscularMeperidineSpinal Cord NeoplasmsSpinal CanalSpinal DiseasesSufentanilNerve BlockLabor PainSpinal Cord CompressionSpinal NeoplasmsAnesthesia, ObstetricalInjections, Intra-ArticularSpinal StenosisInjections, SubcutaneousSpinal FusionRats, Sprague-DawleyLabor, ObstetricInjections, EpiduralPain ThresholdDouble-Blind MethodNaloxoneAmidesHyperalgesiaLidocaineInjections, IntralesionalAnalgesics, Non-NarcoticGanglia, SpinalTramadolSpinal InjuriesMuscular Atrophy, SpinalTime FactorsInjections, IntraventricularCesarean SectionDrug ToleranceInjections, IntraperitonealReceptors, Opioid, muDose-Response Relationship, DrugSpinal Cord IschemiaClonidinePregnancyPosterior Horn CellsPostoperative Nausea and VomitingNociceptorsPain ManagementMotor NeuronsAnesthesia, GeneralInterpleural AnalgesiaThoracic VertebraeSpineKetorolacDisease Models, AnimalKetamineConscious SedationNarcotic AntagonistsLumbosacral RegionHematoma, Epidural, SpinalReceptors, OpioidInjections, IntradermalParaplegiaFemoral NerveAnesthesia, CaudalEpidural SpaceTuberculosis, SpinalLaminectomyNeuralgiaHydromorphoneLumbar VertebraeLabor Stage, FirstTreatment OutcomeProspective StudiesOpioid PeptidesSpinal CurvaturesBehavior, AnimalHypnotics and SedativesAnesthesia and AnalgesiaSubarachnoid Space