Ossification of posterior longitudinal ligaments (OPLL) is defined as a chronically progressive disease of ectopic endochondral and membranous ossification of the posterior longitudinal ligaments of unknown etiology
Etiology
Multifactor condition.
COLA1, COLA2, and NPPS genes are associated with the origin of OPLL
Posterior longitudinal ligament
↓
2 layered
↓
- Superficial ( Close contact with dura and bridges 3 or 4 layers)
- Deep ( Located posterior to the vertebral bodies and connects 2 adjacent vertebrae)
Incidence: 3% of the Japanese population (Japanese disease)
Mostly occurs in the cervical spine
OPLL can cause
- Spinal stenosis and myelopathy (cord compression)
- Ossified dura mater and fuse with PLL (dural ossification)
The average age of onset is 50 Years
The patient may present with axial neck and upper limb pain, sensory symptoms and muscle weakness in the arm, UMN injuries
Cervical spinal cord injury (SCI) can be induced by minor cervical trauma in the patient with ossification of posterior longitudinal ligaments
Diagnosis
Diagnostic criteria are:
Radiological:
OPLL visible on lateral view Xray (CT can be useful for better assessment)
Clinical:
Cervical myelopathic symptoms, radicular symptoms, and cervical spine range of motion abnormality
Classification of OPLL
Divided into four types
Continuous
Long lesion extending into several vertebrae
Segmental
One or several separate lesions behind vertebrae bodies
Mixed
The combination of continuous and segmental types
Circumscribed
The lesion is mainly located posterior to the disc space
Imaging for OPLL
X-ray shows dense ossification along the back of vertebral bodies
CT Scan shows the double layered sign on the axial bone window, consisting of an anterior (ligamental) and posterior (dural) rim of hyperdense ossification
MRI: Look for the features of myelopathy
Treatment Options
Medical treatment is concerned with symptomatic relief
Options for medical management are
- Analgesics
- Anti-inflammatory
- Anti-depressant
- Anti-convulsant
- Opioids
Gold Standard
Surgical Decompression is Indicated in severe and progressive disease.