Effect of high-dose intravenous dexamethasone on postlumbar discectomy pain

Study Design. A prospective, randomized triple-blind clinical trial. Objective. To evaluate the effect of 40 and 80 mg intravenous (IV) dexamethasone versus placebo to reduce postlumbar diskectomy pain. Summary of Background Data. Lumbar discectomy is a procedure to ablate radicular and low pack pain (LBP) in select patients. Unfortunately, some patients have radicular pain for several days after successful surgery, possibly caused by nerve root inflammation. Methods. A total of 61 patients with single-level herniated lumbar disc at L4-L5 or L5-S1 were randomly assigned to 3 groups. After the skin incision, group 1 received 40 mg, group 2 received 80 mg IV dexamethasone, and group 3 received placebo. All patients also received 50 mg ranitidine IV at the same time. Preoperative and postoperative radicular and LBP were evaluated using the visual analog scale. Morphine was administered and recorded as a sole pain-killer during hospital admission if indicated. Collected data were analyzed using the 1-way analysis of variance test. Results. A total of 61 consecutive patients entered the study. There were 19 patients who received 40 mg dexamethasone IV (group 1), 20 received 80 mg (group 2), and 22 received placebo (group 3). Preoperative data, including age, sex, level of disc herniation, and radicular and LBP, were statistically matched among groups. Postoperative LBP was decreased in all groups equally. Based on the visual analog scale, mean radicular pain was significantly decreased 4.26 points in group 1, 4.15 points in group 2 versus 2.73 points in group 3 (P = 0.006). Mean total morphine used was also significantly lower in group 1 versus group 3 (5.26 vs. 9 mg P = 0.012). Conclusion. Intraoperative IV injection of 40 mg dexamethasone could effectively reduce postoperative radicular leg pain and narcotics usage in patients with single-level herniated lumbar disc.