Ligamentum FlavumOssification, HeterotopicLaminectomyCystsOssification of Posterior Longitudinal LigamentLigamentsSpinal Cord CompressionLongitudinal LigamentsSpinal StenosisThoracic VertebraeEpidural SpaceRadiculopathySpinal DiseasesCervical VertebraeBrevibacteriumLumbar VertebraeHematomaBrevibacterium flavumDecompression, SurgicalElastic TissueSpinal Canal