Clinical Manifestation of Cervical OPLL

Abstract

Ossifi cation of the posterior longitudinal ligament (OPLL), which is most frequently found at the cervical spine, causes several symptoms. OPLL can be detected on lateral plain radiographs, and the diagnosis and morphological details of cervical OPLL have been clearly demonstrated by magnetic resonance imaging (MRI) and computed tomography (CT). The shape and volume of OPLL are quite varied. OPLL is sometimes found in a limited area but often extends over a wide area behind the posterior wall of the vertebral body and disc of the spine, occupying anywhere from less than 10% to more than 50% of the anterior portion of the spinal canal. OPLL is classifi ed into four types on lateral plain radiography: (1) segmental; (2) continuous; (3) mixed; (4) localized [1,2]. The shape is also quite irregular. OPLL is one of the most signifi cant lesions that compromise the spinal canal, causing compression of the spinal cord and the nerve roots in various ways. Because of the varied shape and volume of the OPLL, the clinical syndrome manifests differently among individuals. Clinical symptoms and signs caused by cervical OPLL are categorized as: (1) cervical myelopathy, or a spinal cord lesion with motor and sensory disturbance of the upper and lower limbs, spasticity, and bladder dysfunction; (2) cervical radiculopathy, with pain and sensory disturbance of the upper limbs; and (3) axial discomfort, with pain and stiffness around the neck. Usually these syndromes are combined to various degrees. Cervical myelopathy, or a spinal cord lesion, is the essential syndrome because OPLL basically compresses the spinal cord under the narrow spinal canal, and the compressed cord produces severe disturbance of the activities of daily living [3,4]. The clinical syndrome of cervical OPLL mostly develops insidiously, and the time of onset is usually unclear. However, occasionally there is an acute spinal cord injury after an accidental fall or a hyperextension force to the neck. Rarely, OPLL is found while screening during a medical checkup of a patient with no symptoms. When OPLL is found in a person who has no symptoms or discomfort, the ossifi cation is considered to be a radiographic fi nding in the spine, such as a degenerative change. The formation and growth of OPLL are thought to occur slowly, so OPLL is not always symptomatic. In cases in which cervical OPLL is found by radiography, the syndrome might manifest at various degrees of severity—from no symptoms to severe paralysis. The clinical entity of cervical OPLL can be defi ned as neurological complaints or defi cits or as annoying discomfort around the neck originating from the compressed or entrapped neural tissues caused by OPLL of the cervical spine.