Comparison of the Preventive Effect of Local Infiltration of Magnesium Sulfate and Bupivacaine on Postoperative Pain in Lumbar Fusion Surgery under General Anesthesia

This study aimed to compare the preventive effect of local infiltration of magnesium sulfate and bupivacaine on postoperative pain in lumbar fusion surgery under general anesthesia.

In a double-blind clinical trial study, 60 candidates for lumbar fusion surgery during 2018-19 in Alzahra hospital, Isfahan, Iran, were randomly divided into three groups. In the first group, magnesium sulfate, in the second group, bupivacaine, and in the third group, normal saline was infiltrated at surgery site. The severity of the pain, the amount of morphine received, and hemodynamic data were recorded and compared before and after operation, immediately after surgery, every 15 minutes until the end of recovery, and 1, 2, 6, 12, 18, and 24 hours after recovery.

The mean pain severity was not significantly different in the preoperative groups at 12, 18, and 24 hours after the test; but, at 2, 6, and 8 hours after the operation, the pain severity was significantly less in magnesium sulfate group compared to the other two groups. The median morphine obtained in 24 hours after surgery was significantly less, and the first time to receive morphine was in magnesium sulfate group more in magnesium sulfate group compared to the other two groups.

It seems that infusion of magnesium sulfate at the site of fusion surgery has been associated with prolongation of the first time to receive morphine by patients, reducing the amount of morphine received, and pain intensity up to 24 hours after surgery.