Gas myelography in the investigation of occult spinal dysraphism.

In patients presenting with suspected spinal dysraphism of the occult type, particularly children, cisternal gas myelography is coming to be accepted as the radiological investigation of choice. The technique of the examination as performed on 40 such patients is described in detail. There have been no complications. Twenty-five patients showed abnormalities of the cord together with low termination and abnormal fixation of the conus. The visualization was excellent in terms both of reliability and detail. The reasons for the difficulties in demonstrating these lesions using positive contrast and for preferring gas myelography are discussed.