Abstract
In the case of isthmic spondylolisthesis, intervertebral foramen becomes a hidden zone. It is extremely difficult to make a differentiation of the pathogenesis by myelogram and CTM. In order to elucidate the pathogenesis of radicular pain, a detailed study was conducted with emphasis placed on MRI coronal images and radiculogram.
Of the 78 patients who underwent microdecompression in our department during the past 11 years from 1988 to 1999, a study was carried out on 47 cases whose MRI coronal images and radiculogram could be reviewed. The mean age at the time of operation was 57. The study was conducted of the compression morphology and the compression site of the disturbed nerve root.
Abnormal MRI findings were observed in 21 out of 47 cases (45%).
The radiculogram revealed abnormal pathways of the nerve sheath in 43 out of 47 cases (91%). The number of cases with abnormal nerve sheath pathways being observed around the isthmus accounted for about 70%. Radiculogram is useful for radiographic evaluation, and the pathogenesis of radiculopathy of isthmic spondylolisthesis was mainly compressive entrapment around the isthmus. We suspect that the accurate understanding of the pathogenesis will leads us to select a surgical procedure with minimal invasion.
