[Intradural herniated disk: report of 2 cases].
Taking advantage of the observation of 2 instances of intradural disk herniation, the authors examine the pathogenetic, clinical, diagnostic, and therapeutic aspects of this rare occurrence in light of a review of the literature and their own observations. Of the theories as to the cause of the syndrome, two appear worth noting: the relative immobility of the dural sac, bound by the surrounding nerve roots; the inflammatory and cicatricial adhesions that establish themselves between the posterior longitudinal ligament and the dural sac. The clinical features as well as the laboratory and diagnostic tests suggest compression of one or more nerve roots similar to that caused by other intradural expansion processes. The onset can be sudden and acute or delayed depending on whether the dural sac adhesions were present before disk herniation or appeared at a later stage. Intradural disk herniation must be checked for, often intraoperatively, in all cases of radiculopathy due to intradural compression. Error in the assessment of the level of the lesion, concomitant extruded extradural disk herniation, or failure to recognize the immobility of the dural sac can all lead to misdiagnosis of intradural disk herniation if the search for this syndrome is not correctly carried out.