A rare neurological presentation due to ossification of the posterior longitudinal ligament of the thoracic spine and ankylosing spondylitis: Case report

Ossification of the posterior longitudinal ligament (OPLL) may be associated with certain rheumatic conditions including ankylosing spondylitis (AS), diffuse idiopathic skeletal hyperostosis (DISH) or spondylosis. More than 95% of all OPLL are localized at the cervical spine. Herein, we report a case of OPLL at the thoracic spine in an HLA-B₂₇-positive female patient with ankylosing spondylitis. The patient was presented to us with spastic paraparesis. The imaging studies included plain roentgenograms, tomograms, myelo-CT and magnetic resonance imaging (MRI). A continuous rod-like ossification along the posterior aspects of the fourth to sixth thoracic vertebrae with spinal cord compression was noted. The patient underwent a laminectomy from T4 to T6. At the second year follow-up examination, residual upper back soreness and mild left thigh pain were noted. However, the patient had resumed a full daily schedule and could walk freely without any support.