“…This consists not only of incisional pain, but dysesthetic pain in the lower extremities as well [1,2,20]. In patients undergoing thoracoabdominal or spine procedures, epidu ral opioids have been shown to provide highly effective analgesia with an extended analgesic effect and minimal sedation [21][22][23], However, opioid side effects, including nausea, vomiting, pruritus, urinary retention, and respira tory depression, still occur in 20-50% of patients [24,25]. The untoward side effects that occur with epidural mor phine appear to be primarily mediated by the mu receptors [26,27], By adding a narcotic agonist/antagonist such as butorphanol, one may selectively block the mu receptors without significantly decreasing analgesia.…”