Wound Infiltration and Instillation Technique for Postoperative Analgesia Using Bupivacaine in Patients Undergoing Lumbar Spine Surgeries

Background: Pain relief after surgery continues to be a major medical challenge in clinical practice. Lumbar spine surgery is associated with significant postoperative pain. Providing optimal analgesia locally in the area of surgical wound, with little systemic side-effects, is a favourable option and has become an intrinsic part of multimodal analgesia. We aimed to assess and compare the effectiveness of local infiltration and instillation of bupivacaine for postoperative analgesia in patients undergoing lumbar spine surgery. Materials and methods: Forty-four adult patients of the American Society of Anesthesiologists (ASA) class I and II were randomly assigned into two groups, incorporating 22 patients per group. After the completion of lumbar spine surgery and after hemostasis was achieved, patients in group A received instillation of 20 ml of 0.25% bupivacaine at the surgical wound site and patients in group B received 20 ml of 0.25% bupivacaine infiltration into the paravertebral muscles on either side. Postoperative numerical rating scale (NRS) pain scores at 1, 2, 3, 4, 5, 6, 7, 8, 14, 20, and 24 hours; the time to first analgesic required, total rescue analgesic consumption, and adverse effects were recorded. Statistical analysis was done using IBM SPSS Statistics for Windows, Version 20.0 (Released 2011; IBM Corp, Armonk, New York, United States). Results: Time to the first analgesic requirement was significantly longer in group A (12.39±1.56 hours) compared to the B group (2.48±0.58 hours) (P < 0.001). The amount of rescue analgesia (diclofenac sodium) required was significantly higher in group B (135.00±46.17 milligrams) compared to A (93.75±33.32 milligrams) (P = 0.001). The number of analgesic demands was higher in the infiltration group compared to the instillation group and was observed to be statistically significant. Hemodynamic parameters remained comparable between the groups. Conclusion: Local instillation of surgical wound site provided better pain control than infiltration technique and is effective and safe postoperative analgesia in patients undergoing laminectomy surgeries.