[Lateral radiculography in the vertical position for the diagnosis of narrow lumbar canal].
Results obtained in 66 cases emphasize the value of lateral imaging to increase sensibility of radiculography in the diagnosis of narrow lumbar canal. In all cases, in fact, the anteroposterior diameter of the opacified canal diminished in the standing position in proportions varying from 20 to 50%, and furthermore, in 20% of patients diagnosis was only possible from this image. Narrowing of the canal was considered as being present in patients with an anteroposterior canal diameter in the standing position that was less than 11 mm in corrected values. This image appears therefore to be an essential one, particularly as clinical symptomatology of narrow lumbar canal is very often atypical (62% of cases). Moreover, contrary to widespread opinions, computed tomography is sometimes less sensitive than radiculography in this type of disorder.