Spinal Nerve RootsSpinal NervesPeripheral Nervous System NeoplasmsNerve Compression SyndromesSpinal CordLumbosacral RegionRadiculopathyLumbar VertebraeNeuralgiaSpinal Cord InjuriesInjections, SpinalMagnetic Resonance ImagingSciatic NerveSciaticaPeripheral Nerve InjuriesLigationPeripheral NervesLumbosacral PlexusGanglia, SpinalHyperalgesiaPeripheral Nervous System DiseasesNerve FibersCauda EquinaIntervertebral Disc DisplacementNerve BlockSpinal CanalSpinal Cord NeoplasmsRats, Sprague-DawleySpinal StenosisCervical VertebraePainSacrumPain MeasurementMyelographyPain ThresholdEpidural SpaceOptic NerveSpinal DiseasesNerve RegenerationSpinal Cord DiseasesSpinal Cord CompressionLaminectomyCervical PlexusMononeuropathiesRhizotomy