Lumbar epidurography and epidural analgesia in cancer patients

Abstract

In an attempt to clarify the correlation between the spread of a local anesthetic and a radiographic contrast medium in the epidural space, a lumbar epidural catheter was inserted in 21 cancer patients. In group I, 10 patients, a single dose of bupivacaine 0.5%, 8 ml, was injected. The epidural block was evaluated by assessing loss of pin-prick sensation. The following day a contrast medium, iohexol 180 mg I/ml, 1.2 ml, was injected and the position of the catheter determined. A second dose of iohexol 180 mg I/ml, 8 ml, was injected and epidurograms were taken. The vertebral spread was measured in cephalad and caudad directions from the catheter tip. Group II, 11 patients, underwent the same procedures as group I with the exception of the volumes injected. On the first day they were given bupivacaine 0.5%, 16 ml, and on the second day iohexol 180 mg I/ml, 1.2 ml by 16 ml. In both groups the position of the patients was supine and the speed of injection standardized. In group I there was no statistically significant correlation between the spread of contrast medium and the extension of the epidural block either in the cephalad or in the caudad direction. In group II there was a statistically significant correlation in both the cephalad and caudad direction. It is concluded that epidurography can provide an estimate of the epidural block, but cannot predict the exact segmental distribution of the block.

Distribution of Contrast Medium Epidurally Injected at Thoracic and Lumbar Vertebral Segments

“…Epidurography using a contrast medium has been used to conjugate the distribution of local anesthetic in the epidural space in humans [10,13,15]. It has been also used to observe the pattern of spread in animals [4,6,12].…”

“…High CT values indicated that a greater amount of contrast medium was distributed in the thoracic vertebral region when it was epidurally injected from the thoracic level; meanwhile, more contrast medium was distributed in the lumbar region when it was injected from the lumbar level. Although the relationship between the spread of contrast medium and the extent of neural blockade is controversial [10,15], yokoyama et al reported the clear correlation between contrast medium distribution and blockade extent in humans. In addition, epidurography has been used to evaluate the distribution of the drugs administered epidurally in animals [4,6,12].…”

Lumbar epidurography with multi‐orifice and single orifice epidural catheters

“…For this reason, epidurography has been used in several studies to determine the position and extent of block [7,8] and has been recommended to confirm the position of epidural catheters sited for long-term use [9].…”

Exaggerated epidural blockade?

“…However, this radiographic examination was not performed through the same catheter, but one re-inserted two interspaces higher than the previous epidural. Previous studies have failed to find a correlation between the spread of contrast in the epidural space and sensory blockade unless larger volumes of dye are used [2,3]. The block at L, in this case may have been due to mechanical obstruction, but could also have arisen as a result of the curve of the thoraco-lumbar spine which would encourage upward spread of this small volume of dye.…”