Evaluation of the effects of caudal or cephalic epidural catheterization on the characteristics of lumbar epidural anesthesia.

Background: The delayed and incomplete sensory block of the sacral roots in epidural anesthesia often results from too huge the size of the first sacral nerve root. To overcome the problem, the enhancement of anesthetic effect on the sacral segment by injecting the local anesthetic toward the caudal direction has been reported. Thus, in this study, we compared the anesthetic effects of epidural anesthesia by catheterization toward caudal direction with that toward cephalic direction on the areas innervated by the sacral nerve roots.