Pathomechanism of Thoracic Disk Herniation: A Postmortem Histological Study

IntroductionKokubun et al histologically demonstrated that herniated masses in all cases of cervical disk herniation contained cartilaginous endplate (CEP) fragments (Spine 1996). They also revealed that the CEP-type of herniation was the predominant type of herniation in the cervical spine resulting from horizontal and vertical cleft formations of the disks at the final stage of the degeneration. On the other hand, it is generally understood that herniated tissues in the lumbar spine can consist of nucleus pulposus and anulus fibrosus, and that lumbar disk herniation does not necessarily happen at the final stage of disk degeneration. However, to our knowledge, the histological features of the herniated masses in thoracic disk herniation have not yet been clarified. In the present study, intervertebral disks from autopsy cases were examined histologically as to elucidate the pathomechanism of thoracic disk herniation.Materials and MethodsSpecimens of 240 intervertebral disks from T1-T2 to T12-L1 were obt...