The Arnold-Chiari malformation.

During the last 12 years several publications have appeared on the x-ray diagnosis of the ArnoldChiari malformation. The ordinary radiological examination of the skull and spinal column in these cases only reveals associated anomalies, such as bony abnormalities of the cranio-vertebral junction, deformation of the cervical spine, and spina bifida. Although these facts in conjunction with the clinical findings may suggest the presence of an Arnold-Chiari deformity, they do not establish the diagnosis. On the other hand several cases have been reported in which the Arnold-Chiari deformity was not associated with other bony abnormalities (Aring, 1938; McConnell and Parker, 1938; Ogryzlo, 1942; Bucy and Lichtenstein, 1945; Epstein, 1948; Swanson and Fincher, 1949; Gardner and Goodall, 1950). It is apparent that direct radiographic demonstration of the Arnold-Chiari deformity requires special methods. List (1941) was the first to apply myelography as a diagnostic procedure in these cases and he found that the iodized oil was arrested in the high cervical region with a concave filling defect. Adams, Schatzki, and Scoville (1941) gave a more detailed description of the myelographic findings in their case, differentiating it from those found in a high cervical cord tumour. Similar reports were published, for example, by Epstein (1948), by Lewin, Wycis, and Young (1950), and by Malis, Cohen, and Gross (1951). All authors mention that some oil passes to the basal intracranial cisterns. The Arnold-Chiari deformity can also be demonstrated by lumbar pneumo-encephalography as was shown by Marks and Livingston (1949) and by Swanson and Fincher (1949). The air may be arrested at the second cervical level and even outline the herniated cerebellar tonsils. Other reports on lumbar pneumo-encephalography in the Arnold-Chiari deformity are less precise on these diagnostic features, but all agree that little or no air enters the ventricles while the intracranial subarachnoid spaces may be visualized. Another advantage of myelography and lumbar pneumo-encephalography is that the swelling of the cervical cord caused by a concomitant hydromyelia may be outlined by the air or oil. As far as we know no mention has been made in the literature of untoward reactions after lumbar puncture. In one of our patients, however (N 7218), a boy aged 17 with basilar impression and ArnoldChiari deformity, the lumbar puncture was followed by quadriplegia and respiratory failure necessitating immediate operative intervention. Fortunately the patient recovered. This patient had never shown any signs of increased intracranial pressure. When the Arnold-Chiari malformation is associated with signs of increased intracranial pressure in adults, we avoid performing myelography or lumbar encephalography, as we think that lumbar puncture is contraindicated in such cases. This report is based on ventriculographic studies of 11 patients in whom the presence of the ArnoldChiari malformation was verified at operation. In all cases the third and fourth ventricles were examined with small quantities of air according to the method described by Ziedses des Plantes (1950).