Breakthrough PainAdministration, BuccalFentanylPain ManagementAnalgesics, OpioidPainLabor PainPain MeasurementAnalgesia, EpiduralDouble-Blind MethodNeoplasmsChronic DiseaseChronic PainPain, PostoperativePain, IntractablePain ClinicsAnalgesicsBack PainAnalgesiaPain ThresholdLow Back PainAcute PainNeck PainDisease ManagementTreatment OutcomeRadionuclide GeneratorsPain PerceptionAbdominal PainFacial PainAnalgesia, Patient-ControlledPalliative CarePelvic PainAnesthetics, LocalNerve BlockMorphine