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Ossification of the Posterior Longitudinal Ligament
 OPLL

General Considerations

  • Heterotopic ossification of the posterior longitudinal ligament
  • Occurs primarily in cervical, most often C4-C5, next most commonly in thoracic spine and least frequently in lumbar spine
  • Most commonly in 40s and 50s
  • Twice as common in males as females
  • Higher prevalence in Asian population, especially Japanese
  • Since OPLL can narrow the spinal canal, most who are symptomatic present with spinal stenosis or  myelopathy
  • Associated with DISH

Clinical Findings

  • Majority of patients have no symptoms
  • Cervical myelopathy is the most common presentation
    • Numbness
    • Neck pain
    • Weakness

Imaging Findings

  • Linear ossification immediately posterior to vertebral body in canal
  • May be continuous (spans several bodies and intervening disc spaces), segmental (occupies back of body but spares disc spaces) or both
  • Predominantly in high cervical spine
  • CT is best at demonstrating ossification
  • On MR, signal behind the vertebral bodies and interbody spaces becomes less dense on all MR imaging sequences as disease progresses

Differential Diagnosis

  • Calcified herniated disc
  • Calcified meningioma
  • Calcified epidural hematoma

Treatment

  • Symptomatic patients may undergo decompression such as by laminectomy

Prognosis

  • Patients with mild cases of OPLL on first discovery rarely progress to severe stenosis
  • Patients presenting with myelopathy are likely to progress

Ossification of the Posterior Longitudinal Ligament (OPLL). Above:Linear ossification just posterior to the posterior border of the cervical vertebral bodies (white arrows). Below: Sagittal reconstruction of cervical spine CT on left shows same flowing ossification (yellow arrow); axial CT demonstrates the ossified posterior longitudinal ligament (blue arrow).
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Inamasu J et al: Ossification of the posterior longitudinal ligament: an update on its biology, epidemiology, and natural history. Neurosurgery. 58(6):1027-39; discussion 1027-39, 2006