Evaluation of the Effect of Perineuronal Morphine on the Quality of Postoperative Analgesia After Axillary Plexus Block

Abstract

A randomized, double-blind study was performed on 50 patients scheduled for elective hand and forearm surgery under axillary plexus block to evaluate the effect of perineuronal morphine on the quality of postoperative analgesia. Patients were divided into two groups. In group A (n = 25) 5 mg of preservative-free morphine in 1.0 mL of 0.9% saline was added to the local anesthetic solution (20 mL of 1% plain lignocaine, 20 mL of 0.5% plain bupivacaine). They also received an intramuscular placebo injection of 1.0 mL of 0.9% saline in the upper thigh. In group B (n = 25), 1.0 mL of 0.9% saline was added to the local anesthetic solution and patients received an intramuscular injection of 5 mg of preservative-free morphine in 1.0 mL of 0.9% saline in the thigh. The addition of morphine to the local anesthetic solution for the axillary block did not shorten the onset time of the block, improve the quality of postoperative pain relief, or provide longer lasting analgesia than that obtained with intramuscular morphine.