Difference in analgesia following epidural blockade in patients with postoperative or chronic low back pain.

Subjective responses of continuous epidural analgesia with bupivacaine were compared in 30 patients with acute (postoperative) or chronic (low back) pain. In the acute pain patients, sensory block was 4 dermatomes at 9 h and 6 dermatomes at 64 h. Corresponding values in the chronic pain patients were 8 and 6 dermatomes respectively.