Spinal Nerve RootsSpinal NervesPeripheral Nervous System NeoplasmsNerve Compression SyndromesSpinal CordLumbosacral RegionRadiculopathyLumbar VertebraeIrritantsNeuralgiaSpinal Cord InjuriesInjections, SpinalMagnetic Resonance ImagingSciatic NerveSciaticaPeripheral Nerve InjuriesLigationSkin Irritancy TestsPeripheral NervesLumbosacral PlexusGanglia, SpinalHyperalgesiaPeripheral Nervous System DiseasesIntervertebral Disc DisplacementNerve FibersCauda EquinaNerve BlockSpinal CanalRats, Sprague-DawleySpinal Cord NeoplasmsPainSpinal StenosisCervical VertebraeSacrumPain MeasurementMyelographyPain ThresholdEpidural SpaceTrigeminal NerveOptic NerveSpinal DiseasesNerve RegenerationSpinal Cord DiseasesSpinal Cord CompressionLaminectomyCervical PlexusNeurons, AfferentDermatitis, IrritantMononeuropathiesRhizotomyPhysical Stimulation