Spinal Cord DiseasesIntervertebral Disc DegenerationIntervertebral DiscIntervertebral Disc DisplacementSpinal CordLumbar VertebraeSpinal FusionMuscular Atrophy, SpinalSpinal Cord InjuriesDiskectomySpinal DiseasesSMN Complex ProteinsTotal Disc ReplacementFibrocartilageProsthesis ImplantationProstheses and ImplantsSurvival of Motor Neuron 1 ProteinInternal FixatorsCervical VertebraeIridoid GlycosidesSpondylolisthesisLow Back PainSpondylosisArthroplastySacrumSpinal StenosisRibonucleoproteins, Small NuclearMotor NeuronsBack PainTreatment OutcomeMagnetic Resonance ImagingAggrecansBone Screws