Spinal Nerve RootsSpinal NervesSpinal CordPeripheral Nervous System NeoplasmsNerve Compression SyndromesLumbosacral RegionRadiculopathyLumbar VertebraeNeuralgiaSpinal Cord InjuriesInjections, SpinalGanglia, SpinalHyperalgesiaPosterior Horn CellsMagnetic Resonance ImagingRhizotomySciatic NerveSciaticaPeripheral Nerve InjuriesLigationPeripheral NervesLumbosacral PlexusRats, Sprague-DawleyPainPeripheral Nervous System DiseasesAxonsNerve FibersCauda EquinaIntervertebral Disc DisplacementNeurons, AfferentNerve BlockPain MeasurementSpinal CanalSpinal Cord NeoplasmsSpinal StenosisPhysical StimulationCervical VertebraeSmad Proteins, Receptor-RegulatedSacrumLIM-Homeodomain ProteinsSensory Receptor CellsMyelographyNociceptorsAfferent PathwaysPain ThresholdEpidural SpaceOptic NerveSpinal DiseasesAnterior Horn CellsNerve RegenerationSpinal Cord DiseasesSpinal Cord CompressionLaminectomyCervical PlexusChick EmbryoMononeuropathies