Ossification of the posterior longitudinal ligament: a review

Ossification of the posterior longitudinal ligament (OPLL) is most commonly found in men, the elderly, and Asian patients. There are many diseases associated with OPLL, such as diffuse idiopathic skeletal hyperostosis, ankylosing spondylitis, and other spondyloarthropathies. Several factors have been reported to be associated with OPLL formation and progression, including genetic, hormonal, environmental, and lifestyle factors. However, the pathogenesis of OPLL is still unclear. Most symptomatic patients with OPLL present with neurological deficits such as myelopathy, radiculopathy, and/or bowel and bladder symptoms. There are some reports of asymptomatic OPLL. Both static and dynamic factors are related to the development of myelopathy. Plain radiography, CT, and MR imaging are used to evaluate OPLL extension and the area of spinal cord compression. Management of OPLL continues to be controversial. Each surgical technique has some advantages and disadvantages, and the choice of operation should be made case by case, depending on the patient's condition, level of pathology, type of OPLL, and the surgeon's experience. In this paper, the authors attempt to review the incidence, pathology, pathogenesis, natural history, clinical presentation, classification, radiological evaluation, and management of OPLL. (DOI: 10.3171/2010.11.FOCUS10276)