[Usefulness and limitations of neuroradiological examinations in lumbar canal stenosis].

Since 1983, we have performed 434 spinal surgery operations. Among them are included 51 cases of lumbar canal stenosis. For these 51 cases, we performed several neuroradiological examinations, such as lumbar plain X-ray, myelography, metrizamide-CT scan (Met-CT) and magnetic resonance imaging (MRI). We discussed and examined the usefulness and limitations of such neuroradiological methods for diagnosis of lumbar canal stenosis. On myelography, these 51 patients were divided into three types; a complete block type with 29 patients, soy-beans type with 7 patients and strangulation type with 15 patients. Myelography could show the level of stenosis, but could give little information about the compressing factors, particularly in complete-block type. Met CT was performed in 37 cases. In both strangulation type and soy-beans type which had been shown through myelography, Met-CT could clearly demonstrate the subarachnoid space, and several structures around the lumbar spinal canal could be clearly identified. In cases which myelography revealed as complete-block type, we identified two subtypes. In the first type subarachnoid space was clearly demonstrated by Met-CT. The second type was comprised of those cases where Met-CT scan could not demonstrate subarachnoid space at all. In the former group, useful information about lumbar canal stenosis could be obtained, but, in the latter, information was scarce. MRI was performed on 21 patients. MRI clearly showed the anatomical relationship of disc, subarachnoid space, yellow ligament and hypertrophied bony structure.(ABSTRACT TRUNCATED AT 250 WORDS)