Spinal Nerve RootsSpinal NervesPeripheral Nervous System NeoplasmsNerve Compression SyndromesSpinal CordLumbosacral RegionRadiculopathyLumbar VertebraePressureNeuralgiaSpinal Cord InjuriesInjections, SpinalMagnetic Resonance ImagingBlood PressureSciatic NerveSciaticaLigationPeripheral Nerve InjuriesPeripheral NervesLumbosacral PlexusGanglia, SpinalHyperalgesiaPeripheral Nervous System DiseasesNerve FibersCauda EquinaIntervertebral Disc DisplacementNerve BlockRats, Sprague-DawleySpinal CanalSpinal Cord NeoplasmsSpinal StenosisCervical VertebraePainPain MeasurementSacrumMyelographyPain ThresholdEpidural SpaceHydrostatic PressureOptic NerveSpinal DiseasesNerve RegenerationSpinal Cord DiseasesCervical PlexusLaminectomySpinal Cord CompressionRhizotomyMononeuropathiesNeurons, AfferentPosterior Horn Cells