effect of instillation of morphine and dexamethasone in epidural space on postoperative pain in discectomy operation

abstract: introduction & objective: discectomy for nucleous pulposus herniation is one of he most surgeries in spinal column. in this surgical treatment, postoperative pain is a problem which results in more hospital stay and less daily activity. postoperative pain control is difficult because opoids don't relieve moderate and severe pain alone. it is believed that corticosteroid and local anesthetic agents or narcotics improve sciatic pain. in this study we compare the effect of different doses of morphine and dexamethasone by placebo on post discectomy operative pain. materials & methods: this is a randomized double blind clinical trial in which 90 selected patients, asa 1-2, with acute-onset herniated nucleus pulposus that were refractory to conservative treatment were enrolled. subjects were randomly divided into 6 groups and underwent discectomy under equal general anesthesia. before the closure operational incision, the first group received 5 cc lidocaine %2, second group 5cc normal saline third group 0.5 mg morphine and 8 mg dexamethasone, forth group 1mg morphine and 8 mg dexamethasone, fifth group 1.5 mg morphine and 8 mg dexamethasone, and the last group 2 mg morphine for every level of discectomy and 8mg dexamethasone . drugs were flushed on dura matter and operation field. volume of all drugs was increased to 6 cc by adding sterile distilled water. postoperative back and radicular pain was scaled 6, 12, 18 and 24 hour after operation using visual analogue scale (vas) and recoded analgesic requirement. collected data was analyzed by spss software using mann whitney u and kruskal-wallis tests. results: patients of group 1 to 3 did not showed significant changes in postoperative pain and consumption of analgesic, but when dose of morphine increased, these changes became significant especially in dose of 2 mg for every level of discectomy. conclusion: it seems that instillation of morphine and dexamethasone in epidural space after discectomy decreases patient’s postoperative pain which result in reduction in narcotic use. www