In order to investigate the changes of myelographic findings after posterior lumbar surgery, iotrolan myelography was performed in 73 cases of lumbar disc herniation and 25 cases of lumbar spinal stenosis. Postoperative myelography was performed 4 weeks after surgery.
In the cases of disc herniation, the findings of cauda equina shifting and double shadow of dural tube were well improved, but the finding of nerve root sleeve defect was poorly improved.
In the cases of spinal stenosis, the findings of dural tube stenosis and block were well improved, but the finding of nerve root sleeve defect was poorly improved. It is suspected that the myelographic findings which were due to extradural mechanical compression are well improved, but that the finding of the root sleeve defect which was due to that mechanical compression and adhesion in and around the root sleeve is poorly improved. The improvement of root sleeve defect was observed in 38% of disc herniation and 24% of spinal stenosis. And many of these cases showed good clinical results.
