Myelopathy caused by retro-odontoid disc hernia: case report.

Abstract

Among masses in the craniovertebral junction causing severe compression of the medulla and upper cervical cord, cases of retro-odontoid disc hernia are extremely rare. We report a case of retro-odontoid disc hernia resulting in severe myelopathy. An 82-year-old man suffered from progressive tetraparesis. Although cervical radiological studies showed marked spondylotic change, no congenital malformations or traumatic lesions were identified. Magnetic resonance imaging disclosed a retro-odontoid soft tissue mass with peripheral enhancement compressing the medulla and the upper cervical cord posteriorly. The patient underwent surgery through the posterior approach. The histopathological examination of the surgical specimen revealed fibrocartilage accompanied by reactive vascular tissue; the mass was diagnosed as a retro-odontoid disc hernia. In the differential diagnosis of mass lesions compressing the neural structures in the craniovertebral junction, retro-odontoid disc hernia, although extremely rare, should be considered to be one possibility. The posterior approach with wide laminectomies provides a good operative field from which to remove the retro-odontoid mass and is especially adequate for elderly patients, because it is less invasive than other procedures.