Thoracic myelopathy due to ossification of the ligamentum flavum

Thoracic myelopathy due to ossification of ligamentum flavum was considered extremely rare in the non-asiatic population. The authors report on their experience with eight north-African patients. Clinical features of patients were: pseudoclaudication, spastic lower limbs and evidence of posterior column dysfunction. Computerized Myelography (4 patients) and recently MRI (4 patients) revealed the diagnosis. Four patients were explored by 3D CT Scanning. Histological examination disclosed ossified tissue in the ligamentum in 7 cases. One patient had calcifications with crystalline material. It was confirmed to be chondrocalcinosis with polarized light microscopy. The latter case is considered to be the first case in the literature. We conclude that this type myelopathy is probably underestimated in our population. 3 D CT Scan constitutes an important tool to determine the elements of the compression. Chondrocalcinosis must be considered as a differential diagnosis in dorsal myelopathy.