The Effects of Bupivacaine on Postoperative Back Pain After Lumbar Laminectomy: A Randomized Clinical Trial

Patients undergoing lumbar laminectomy experience severe pain in the postoperative period, which may increase the incidence of postoperative morbidity and complications. This study determined the effect of bupivacaine on postoperative back pain after lumbar laminectomy. Sixty consecutive patients who underwent posterior approach laminectomy were randomly allocated to control and study groups. Anesthesia was induced with intravenous midazolam, fentanyl, and morphine. Tracheal intubation was facilitated by Atra, and patients’ lungs were ventilated with a mixture of 66% nitrous oxide and 0.5% to 1% halothane in oxygen. Anesthesia was continued with panthotal. Before wound closure in the study group, the surgeon injected 30 mL of 0.25% bupivacaine in paravertebral muscle and 30 mL of normal saline at the same site in the control group. Pain was assessed at rest on a linear visual analog scale at 6 and 12 hours after surgery. Also, the size of incision was recorded in all patients. No difference was noticed for pain intensity scores in different age groups. Level of education did not influence the pain tolerance and there was no relation between increases in size of incision and pain intensity. In the study group, after 6 and 12 hours postoperatively, female patients had more visual analog scale values than male patients, which was more significant statistically after 6 hours postoperatively when compared with 12 hours postoperatively. Regarding education and pain perception, there was no significant correlation. There was no statistical difference for age between groups. As injection of bupivacaine in paravertebral muscles did not diminish the postoperative back pain experienced by the patients and no difference was noticed in pain intensity scores between groups, our findings denote to ineffectiveness of local bupivacaine in postoperative back pain.