The validity of upright myelography for diagnosing lumbar disc herniation.

Although computed tomographic (CT) myelography and magnetic resonance imaging (MRI) are used for assessing lumbar disc herniations (LDH), they cannot provide images when patients are standing or walking, whose CT myelograms and MRI images show only slight disc bulging. The purpose of this study was to evaluate the usefulness of upright myelography. We examined by myelography in both an upright and a lying position for 50 patients with LDH at L4-5 and L5-S1 to assess the difference in disc bulge size. Lateral myelogram was used for evaluating the difference quantitatively. In 29 patients with damage at L4-5, 21 (72.4%) had increased disc bulging when upright, and 22 (75.9%) showed subligamentous LDH. In 21 patients with damage at L5-S1, fewer patients showed increased disc bulging when upright than showed unchanged disc bulging. This upright myelographic technique could show increased disc bulging in patients with mild compression at L4-5 whose sciatica increased in an upright position. Upright myelography seems to be the only method for assessing patients with LDH, especially at the L4-5 level, whose neurological symptoms develop during standing or walking.