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.