Comparison the effect of bupivacaine plus magnesium sulfate with ropivacaine plus magnesium sulfate infiltration on postoperative pain in patients undergoing lumbar laminectomy with general anesthesia

Purpose In this study, we investigated the effect of local injection of ropivacaine and bupivacaine with magnesium sulfate on postoperative pain in vertebral laminectomy surgery. Design This randomized double-blind prospective study was conducted among 60 patients aged 18-65 years old with ASA class I and II. Methods Group RM: (30 people) received 70 mg ropivacaine (14 ml) plus 1 ml magnesium sulfate (500 mg) volume up to 20 ml with normal saline. Group BM: (30 people) received 70 mg bupivacaine (14 ml) plus 1 ml magnesium sulfate (500 mg) volume up to 20 ml with normal saline. The results were analyzed by SPSS 23 software, and statistical analysis consisted of chi (2) test and t-test, and a p value less than .05 was considered significant. Findings Mean pain score based on VAS in 6 and 12 h after surgery in the RM group was lower in the BM group (p < 0.05). The analgesic request frequency in the RM group was lower than the BM group (p = 0.01). The mean morphine consumption in the RM group was 185 mg and in the BM group was 220 mg. According to the T-test, there was a significant difference between the two groups (p = 0.03). there was no significant difference between the mean arterial blood pressure and mean heart rate between the two groups at 6, 12, 24 and 24 h after surgery (p > 0.05). Conclusion This study showed that wound infiltration with ropivacaine and magnesium sulfate compared to bupivacaine and magnesium sulfate provided better postoperative analgesia and significantly reduced postoperative opioid consumption in patients undergoing lumbar laminectomy.