Choice of Surgical Procedures for Thoracic Ossification of the Posterior Longitudinal Ligament

Thoracic myelopathy caused by ossifi cation of the posterior longitudinal ligament (OPLL) is rare compared to cervical OPLL, even in the Japanese population. However, once myelopathy appears in patients with thoracic OPLL, it is progressive and often leads to serious paraplegia. In such cases, surgical treatment is required because conservative treatment, such as immobilization by a brace, is not effective. The mechanical stability of the upper and middle thoracic spine is greater than that of the cervical spine. Therefore, with thoracic OPLL, the static factor—compression of the spinal cord from the anterior aspect—is a major factor for the progression of myelopathy rather than the dynamic factor. When myelopathy is mild, both surgeons and patients sometimes hesitate to undertake surgery because of the potential risk of the neurological complications that might occur. As myelopathy progresses, the risk of surgery increases, which presents a dilemma for both patients and surgeons.