Multiple-level ossification of the ligamentum flavum in the cervical spine combined with calcification of the cervical ligamentum flavum and posterior atlanto-axial membrane.

Abstract

Ossification of the ligamentum flavum (OLF) is rarely identified in cervical spine and its pathogenesis has not been established. We report a case of multiple-level OLF, combined with the calcification of the cervical ligamentum flavum and posterior atlanto-axial membrane. A 42-year-old man without any systemic background presented with one month history of pain from the neck to the right shoulder and right leg numbness. Cervical computed tomography demonstrated OLF from C2 to C5, a small area of calcification of the ligamentum flavum (CLF) from C5/6 to C7/T1 and extensive calcification of the posterior atlanto-axial membrane, resulting in spinal canal stenosis. Magnetic resonance imaging showed spinal canal stenosis and severe spinal cord compression from C2 to C5. Thoracic X-ray also showed ossification of the posterior longitudinal ligament (OPLL). We performed laminectomy from C1 to C5 and resected the calcified posterior atlanto-axial membrane and OLF. Histopathological examination demonstrated calcified granules within degenerated fibrous tissue in the posterior atlanto-axial membrane and mature bony trabeculae, bone marrow and residual ligament tissue in the OLF. Simultaneous development of cervical OLF and CLF in this case seems unlikely to have occurred coincidentally and suggests that the pathogenesis of OLF and CLF may share a common initiation factor.