Severe Lumbar Spinal Canal Stenosis Due to Co-occurrence of Ossification of the Ligamentum Flavum and Posterior Longitudinal Ligament.

This report describes a rare and challenging case of severe lumbar spinal canal stenosis resulting from extensive, concurrent lumbar ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF). A 44-year-old female patient who initially presented with numbness and gait instability due to thoracic spinal cord compression was successfully managed by thoracic decompression and fusion. However, she subsequently developed lower back pain, buttock pain, and numbness along both legs due to severe multilevel lumbar stenosis from L2 to L5. Surgical management involved multilevel posterior laminectomy with careful removal of extensive ossified ligaments. Postoperatively, the patient's symptoms improved, and lumbar alignment was maintained without the need for fusion. This case highlights the surgical complexity of extensive multilevel lumbar ossification and the necessity of comprehensive whole-spine evaluations in managing spinal ligament ossification. Timely surgical intervention is also crucial in preventing permanent neurological deficits.