[Non-discal sciatica secondary to a cystic lesion of the posterior longitudinal ligament. 10 cases].

Cyst of the longitudinal posterior ligament of the spine is a new entity described here on the basis of 10 cases. This is a lesion, perhaps of traumatic origin, which occurs in young, athletic subjects suffering from classical lumbosciatica. Computerized tomography showed an image resembling nucleus pulposus herniation. In one of our cases magnetic resonance imaging provided the preoperative diagnosis. Following surgery the outcome was favourable, with less postoperative complications than with discal herniation. The macroscopic and histological findings were the same in all cases, making the anatomico-pathological diagnosis easy.