Ossification of the posterior longitudinal ligament (OPLL) as cause of cervical myelopathy: A Case Report

Case Diagnosis: A 64-year-old male with a nonspecific neurologic presentation is found to have severe cervical myelopathy secondary to ossification of the posterior longitudinal ligament (OPLL).

Case Description or Program Description: The patient presented for evaluation of low back pain with reported history of diffuse idiopathic skeletal hyperostosis (DISH) and severe cervical stenosis. Prior imaging was not available at initial visit. On presentation, the patient described dull, aching pain localized to the lumbar spine. He denied upper or lower extremity radiculopathy symptoms, bowel or bladder incontinence, or saddle anesthesia. Physical examination revealed generalized lumbar stiffness with full strength in the upper extremities and 4/5 strength through the lower extremities. He demonstrated unilateral 3+ hyper-reflexia in the left lower extremity. Provocative maneuvers did not incite radiculopathy symptoms. Bilateral upper extremities and cranial nerves remained neurologically intact. Cervical MRI imaging was ordered and revealed marked ossification of the posterior longitudinal ligament causing severe canal narrowing from C2 to C6, with significant cord compression and myelomalacia. Lumbar MRI demonstrated anterior osteophytes consistent with DISH and severe facet arthropathy, without significant stenosis.

Setting: Outpatient clinic.

Assessment/Results: Despite a subtle neurologic presentation, the patient’s history and presence of asymmetric hyper-reflexia led providers to obtain imaging beyond the lumbar spine, revealing severe cervical myelopathy. Patient is now pending neurosurgical evaluation.

Discussion (relevance): OPLL is associated with DISH in up to 50% of cases, and theorized to have a genetic component. OPLL primarily occurs in the cervical spine and may simply manifest as lower extremity weakness or difficulties with fine motor skills. This case highlights the need for thorough evaluation and consideration of rare conditions in patients presenting with a nonspecific neurologic exam.

Conclusions: Patients may lack significant pain or neurologic findings despite evidence of severe cervical cord pathology secondary to OPLL. Advanced imaging is important to elucidate the extent of stenosis as physical exam may not be proportional.