[Sciatica and nerve root anomalies. Apropos of a series of 20 cases].

We present 20 operative cases of lumbar nerve root anomalies, divided into 6 anatomical types: nerve roots with common dural emergence (4 cases), contiguous dural emergence (6 cases), with common dural sheath (4 cases), splited nerve roots (2 cases), anastomosis between roots (3 cases) and plexiform nerve roots (1 case). 14 cases are associated with a discal hernia. 10 cases presented with unilateral but biradicular sciatica.