Ossification of Posterior Longitudinal LigamentLongitudinal LigamentsOssification, HeterotopicLigamentsCervical VertebraeLigamentum FlavumSpinal Cord CompressionHyperostosis, Diffuse Idiopathic SkeletalDecompression, SurgicalLaminectomySpinal Cord DiseasesSpondylosisSpinal StenosisSpinal OsteophytosisSpinal FusionSpinal DiseasesIntervertebral DiscQuadriplegiaSpineLigaments, ArticularThoracic VertebraeIntervertebral Disc DisplacementRadiculopathyTomography, X-Ray ComputedLumbar VertebraeMagnetic Resonance ImagingPeriodontal LigamentTreatment OutcomePosterior Cruciate Ligament