Longitudinal LigamentsOssification of Posterior Longitudinal LigamentHyperostosis, Diffuse Idiopathic SkeletalCervical VertebraeLigamentsOssification, HeterotopicLigamentum FlavumSpinal Cord CompressionLigaments, ArticularDecompression, SurgicalLaminectomySpinal Cord DiseasesSpondylosisSpinal StenosisSpinal DiseasesSpinal OsteophytosisIntervertebral DiscPeriodontal LigamentSpinal Fusion