What is OPLL (Ossification of the Posterior Longitudinal Ligament)?

From the Guidelines

OPLL stands for Ossification of the Posterior Longitudinal Ligament, a condition where the ligament running along the back of the spine becomes hardened and calcified, as described in the study by 1. This condition can cause the ligament to thicken, potentially compressing the spinal cord and nerve roots, leading to symptoms like neck pain, stiffness, numbness or tingling in the arms and legs, and in severe cases, difficulty walking or loss of bladder control.

Key Points

• OPLL most commonly affects the cervical spine (neck region) and is more prevalent in Asian populations, particularly Japanese individuals, with a reported prevalence rate of cervical OPLL between 1.7% in the white United States population and 4.6% in the Korean population, as noted in the study by 1.
• Treatment options depend on symptom severity, ranging from conservative approaches like physical therapy and pain medications for mild cases to surgical decompression for severe spinal cord compression.
• The condition is typically diagnosed through imaging studies such as X-rays, CT scans, or MRIs, with CT being more reliable in the identification of OPLL and evaluation of its sequelae, as stated in the study by 1.
• OPLL tends to progress slowly over time, and regular monitoring is important to prevent serious neurological complications.

Diagnosis and Imaging

• CT evaluation can show OPLL type, thickness, length of involved segments, and associated systemic diseases, making it a crucial diagnostic tool, as mentioned in the study by 1.
• MRI is useful in assessing cord abutment/signal changes secondary to spinal canal narrowing and evaluating the exiting nerve roots in the setting of radiculopathy, despite its limited sensitivity in detecting OPLL, as reported in the study by 1.

From the Research

Definition of OPLL

• Ossification of the Posterior Longitudinal Ligament (OPLL) is a multifactorial condition caused by ectopic hyperostosis and calcification of the posterior longitudinal ligament 2.
• It is a hyperostotic condition that results in ectopic bone formation and calcification of the posterior longitudinal ligament 3.
• OPLL occurs as heterotopic bone forms in the posterior longitudinal ligament, resulting in neural compression, myelopathy, and radiculopathy 4.

Etiology and Epidemiology

• The etiology of OPLL is multifactorial, including genetic, metabolic, and anatomic factors 2, 4.
• Familial inheritance and genetic factors have been implicated in the etiology of OPLL 2.
• OPLL is most commonly observed in East Asian populations, with prevalence rates of 1.9% to 4.3% reported in Japan 4.
• OPLL rates are lower in North American and European patients, with reported prevalence of 0.1% to 1.7% 4.

Clinical Presentation and Management

• The clinical manifestations of OPLL range from asymptomatic to myelopathy or myeloradiculopathy 2.
• Asymptomatic patients typically can be managed nonoperatively, while surgical treatment is reserved for patients presenting with myelopathy and worsening radiculopathy that has not responded to conservative treatment 3.
• The decision to use anterior, posterior, or combined anterior-posterior approaches should be an individualized decision that considers the degree of OPLL pathology, K-line imaging findings, and other patient-specific risk factors 3.
• Surgical treatment can provide notable improvement in neurologic function 4.