Rapidly Progressive Calcification of the Cervical Ligamentum Flavum and Cervical Myelopathy: A Case Report

Cervical calcification of the ligamentum flavum is a relatively rare disease that causes myelopathy due to calcification within the ligament. We recently encountered a patient with rapid progression of cervical calcification of the ligamentum flavum after anterior fixation surgery, resulting in spinal cord symptoms. An 81-year-old woman had a history of anterior decompression and fixation surgery (Williams-Isu method) at C3-4 and C5-6 at the age of 58 years, with no sequelae. Eighteen months preoperatively, the patient developed walking difficulties, arm pain, and weakness in both arms. Magnetic resonance imaging showed C4-5 anterior spinal cord compression, and C4-5 anterior decompression and fixation surgery were performed. Postoperatively, the patient's condition improved, and she was discharged from the hospital, able to walk unaided. However, 17 months postoperatively, the patient rapidly developed right arm pain, walking difficulties, and urinary and rectal incontinence. There was a rapid progression within 18 months in cervical calcification of the ligamentum flavum at the C6-7 level on magnetic resonance imaging and severe compression of the spinal cord; therefore, urgent laminectomy was performed. Postoperatively, the symptoms improved, and there was no recurrence for 3 years. In addition to the previously performed C3-4 and C5-6 fusion procedures, the addition of a C4-5 fusion resulted in a longer fusion spanning from C3 to C6, and it is thought that mechanical stress was concentrated on the adjacent intervertebral space of C6-7. Although the cause of cervical calcification of the ligamentum flavum has not been determined, this case strongly suggests that mechanical stimulation may exacerbate the condition.