Thoracic cord compression caused by contiguous multilevel ossification of ligamentum flavum in Chinese patients

To explore the epidemiology, clinical presentation, radiology and surgical treatment outcome in Chinese patients with myelopathy caused by contiguous multilevel ossification of ligamentum flavum.

Medical notes and imaging data of 18 Chinese patients (14 males and 4 females, aged 43-72 years, mean: 57 years) with myelopathy caused by contiguous multilevel ossification of ligamentum flavum were studied retrospectively in this article. The diagnosis was based on clinical examination, X-ray films, computerized tomography (CT) and magnetic resonance imaging (MRI) scanning results and pathological results. Sixteen patients were treated by laminectomy and two by laminoplasty. The average follow-up duration was 34 months (range, 28-49 months). The outcome was evaluated by Japanese Orthopaedics Association (JOA) score.

The average time for occurring clinical symptoms was 7.5 months (range, 2 days-16 months). All the 18 cases presented with clinical evidences of chronic and progressive thoracic spinal cord compression, which included bilateral leg weakness, spastic gait, numbness in lower limbs, paresthesia in terminal and perineum, and urinary incontinence. Neurological examination revealed severe spastic paraparesis, absence of abdominal reflexes, and reduction of the sensory function below the compression level. The mean JOA score before operation was 3.6 (range, 0-6). MRI and CT scans of the thoracic spine confirmed the presence of contiguous multilevel ossification of the ligamentum flavum. The mean recovery rate after surgery in terms of JOA score was 66.3% (range, 33.3%-100%), with a mean final JOA score of 8.3. Thoracic decompression laminectomy or laminoplasty could result in a good postoperative outcome.

Contiguous multilevel ossification of the ligamentum flavum is not a common cause of myelopathy in Chinese population and should be treated as early as possible. MRI and CT scan examinations may diagnose the presence of thoracic ossification of ligamentum flavum (OLF). Posterior decompression, especially with en bloc dissection of the laminae, can obtain satisfactory results.