Spinal Nerve RootsSpinal NervesPeripheral Nervous System NeoplasmsNerve Compression SyndromesSpinal CordLumbosacral RegionRadiculopathyLumbar VertebraeAnatomyNeuralgiaSpinal Cord InjuriesInjections, SpinalMagnetic Resonance ImagingSciatic NerveSciaticaPeripheral Nerve InjuriesLigationPeripheral NervesLumbosacral PlexusGanglia, SpinalHyperalgesiaPeripheral Nervous System DiseasesNerve FibersIntervertebral Disc DisplacementCauda EquinaNerve BlockSpinal CanalSpinal Cord NeoplasmsRats, Sprague-DawleyCervical VertebraeSpinal StenosisPainSacrumPain MeasurementMyelographyEpidural SpacePain ThresholdOptic NerveSpinal DiseasesNerve RegenerationSpinal Cord DiseasesSpinal Cord CompressionLaminectomyCervical PlexusTooth RootRhizotomyMononeuropathies