Epidurography in lumbar spondylolisthesis

Spread of radiopaque dye in the thoracic epidural space

A radiological study was performed in 23 patients to look for the position of thoracic epidural catheters and the spread of the contrast medium iohexol 300 mg/ml and 180 mg/ml when used in volumes of 3 and 8 ml. The dye was injected through the epidural catheter just after thoracic surgery. The spread of the dye showed no relation to the injected volume or the sensory spread after 2% lignocaine 3 ml. In three cases no contrast could be seen on the x-ray, and in two the radiopaque dye was found just outside the epidural space. No relationship between the spread of the dye and the sensory blockade was found, but the position of the epidural catheter should be checked radiographically when the epidural route is to be used for long-term pain relief.

Computed tomography application to lumbar epidurography

The application of current-generation computed tomography scanning to lumbar epidurography has resulted in a better appreciation of epidural anatomy and improved ease of interpretation of non-ionic contrast material within the epidural space. The development of extended window width has greatly improved imaging of the more variable levels of attenuation encountered in contrast material within the epidural space. The procedure of distribution of contrast material by catheter technique via the sacral canal approach is described. The experience obtained on examination of 24 patients is discussed, along with the possible adjunctive and primary roles of this type of imaging in evaluation of the lumbar spine.