[The dural sheath in the sitting and standing position during saccoradiculography. Apropos of 150 cases].

Lateral images were studied in the sitting and standing positions during a continuous series of 150 radiculographies, in patients presenting with a symptomatology suggestive of herniated disk or lumbar stenosis. In 67% of cases the dural sac was abnormally reduced at the level of the inter-somatic spaces, due to disk protrusion or intracanalar protrusion of posterior soft tissues. In 23% of cases, an absolute canalar stenosis with anterior-posterior decrease to less than 10 mn in the standing position existed. This was due in 65% of cases to an isolated or predominant posterior impression, the latter appearing in the standing position in only 55% of cases. Saccoradiculography is the only procedure allowing study of the dural cul-de-sac in the standing position. It should be carried out if a narrow lumbar canal is suspected clinically, even if investigations in the lying position, such as CT scan or MR imaging show normal canalar dimensions.