Comparison of bupivacaine and bupivacaine plus magnesium sulphate infiltration for postoperative analgesia in patients undergoing lumbar laminectomy: A prospective randomised double-blinded controlled study

Abstract

AbstractBackground: Laminectomy is associated with considerable postoperative pain. Providing analgesia locally in the area of surgical trauma, with minimal systemic side effects, is an attractive option and has become an integral part of multimodal analgesia. The objective of this study was to assess and compare the effectiveness and safety of local infiltration of bupivacaine and bupivacaine plus magnesium sulphate for postoperative analgesia in patients undergoing lumbar laminectomy. Materials and Methods: Sixty adult patients of the American Society of Anaesthesiologists (ASA) class 1 and 2 were randomly allocated into two groups, comprising 30 patients in each group. After the completion of lumbar laminectomy, the study drug was locally infiltrated into the paravertebral muscles on either side. Group bupivacaine with magnesium (BM) was given 20 ml of 0.25% bupivacaine with 500 mg of magnesium sulphate (constituted with normal saline); and Group bupivacaine (B) was given 20 ml of 0.25% bupivacaine constituted with normal saline. Postoperative visual analogue scale (VAS) pain scores at 1, 2, 4, 6, 8, 12 and 24 hours; rescue analgesia, the time to first analgesic consumption, degree of overall patient satisfaction and side effects were recorded. Comparison of continuous data between groups was done using independent T-test. Comparison of nominal data was done using Chi-square analysis and ordinal data using Mann-Whitney test. A P value less than 0.05 was considered significant. Results: Time to first analgesic consumption was significantly longer in BM group (7.78 ± 1.350 hours) compared to B group (4.62 ± 0.997 hours) (P < 0.0001). The consumption of Tramadol was significantly higher in B group (202.5 ± 76.9 mg) compared to BM (117.5 ± 63.4 mg) (P < 0.0001). The degree of overall satisfaction with postoperative pain management on a 4-point satisfaction scale was better in BM group (2.77 ± 0.626) compared to B group (2.0 ± 0.587) (P < 0.001). Conclusion: Wound infiltration with bupivacaine and magnesium sulphate provided better pain control and analgesic effect was more significant, providing effective and safe postoperative analgesia in patients undergoing laminectomy surgeries.