[Intradural herniation of the intervertebral disk of the lumbar segment of the spine].

The authors present 11 cases of intradural lumbar disc herniations selected from 2030 patients treated surgically for intervertebral disc prolapse. In the light of these cases and a survey of pertinent literature the authors consider that the frequency of intradural disc rupture is very low, it is most often found at LIV-LV space, mainly in men. In these cases the preoperative diagnosis of this condition should be suspected when there is a history of significant chronic low-back pain followed by an acute episode of cauda equina syndrome and presence of a complete or nearly complete block on myelography. In these cases adhesions of dura mater with ligaments were always found. The penetration of an extruded disc through the dura mater has been explained as being due to adhesions that attach the dural sac to the anterior wall of the spinal canal. In the discussion the authors review the contemporary views on the aetiology, possibility of preoperative diagnosis, operation technique and late results.