BupivacaineAnesthetics, LocalAnesthesia, SpinalAnalgesia, EpiduralAmidesAnalgesia, ObstetricalAnesthesia, EpiduralAnesthesia, ObstetricalNerve BlockLidocainePain, PostoperativeAnesthesia, CaudalEtidocaineAnesthesia, LocalSufentanilFentanylAnesthetics, CombinedDouble-Blind MethodAdjuvants, AnesthesiaMepivacaineInjections, SpinalCesarean SectionCarticaineAnalgesics, OpioidPain MeasurementAnalgesiaStereoisomerismSensationSubarachnoid SpaceAnalgesia, Patient-ControlledMorphineBrachial PlexusLabor, ObstetricDose-Response Relationship, DrugProcaineInjections, EpiduralAmbulatory Surgical ProceduresPregnancyPrilocaineEpinephrineSpecific GravitySciatic NerveThoracotomyHernia, Inguinal