Idiopathic spinal cord herniation associated with a large erosive bone defect: a case report and review of the literature.

We report a case of idiopathic spinal cord herniation associated with a large bone defect. MRI and computed tomographic myelography revealed ventral deviation of the spinal cord and erosion of the vertebral body at T6-T7. Microscopic surgery revealed a dural defect. The etiology of this condition has not been clarified. In most previously reported cases, the peak portion of the herniation was around the intervertebral disc space. In addition, in our patient, it was hard to think that the intervertebral disc has become depressed due to the pressure exerted by the spinal cord. We considered that a certain condition of the intervertebral disc, such as herniation, was one of the causes of the dural defect, and cerebrospinal fluid pulsation pushed the spinal cord toward that portion, causing herniation.