Intervertebral Disc ChemolysisIntervertebral DiscIntervertebral Disc DegenerationIntervertebral Disc DisplacementLumbar VertebraeFibrocartilageSpinal DiseasesSpineAggrecansDiskectomyCompressive StrengthCervical VertebraeLumbosacral RegionNotochordChymopapainWeight-BearingSpinal OsteophytosisThoracic VertebraeDiscitis