Role of computed tomography and myelography in the diagnosis of central spinal stenosis.

In order to evaluate radiographic methods for diagnosing central lumbar stenosis, we reviewed the computed tomography scans and myelograms of twenty-four patients who underwent surgical decompression for central lumbar stenosis. In the diagnosis of central lumbar stenosis, the measurement of the anterior-posterior diameter of the osseous canal by computed tomography was less reliable than the measurement of the dural sac by myelography. The dimensions of the canal derived from computed tomography provided a correct diagnosis in 20 per cent of the patients, while myelography was accurate 83 per cent of the time. The effectiveness of computed tomography was improved when the cross-sectional area of the dural sac was measured. We suggest that a narrow dural sac, demonstrated by myelography or by computed tomography, reliably indicates central spinal stenosis.