BaclofenInjections, SpinalInfusion Pumps, ImplantableMuscle Relaxants, CentralMuscle SpasticityInfusions, SpinalInfusion PumpsUrinary Bladder CalculiCystotomyGABA AgonistsDystoniaSpinal Cord InjuriesEquipment FailureCerebral PalsyGABA-B Receptor AgonistsH-ReflexSubstance Withdrawal SyndromeMultiple SclerosisReceptors, GABA-BTreatment OutcomeMorphineSpinal CordFollow-Up StudiesTime FactorsAnalgesics, OpioidAnalgesicsPain MeasurementAnesthesia, SpinalGABA-B Receptor AntagonistsPainRats, Sprague-DawleyHyperalgesiaBupivacaineDose-Response Relationship, DrugAnalgesia, Obstetrical