A comparative study between neostigmine and dexamethasone as an adjuvant to bupivacaine in adductor canal block after knee arthroscopy (RCT)

Abstract

Background Adjuvants to adductor canal block are used to improve the quality and duration of the block for better analgesia after knee surgeries. This study evaluates and compares the effect of adding dexamethasone and neostigmine to bupivacaine in adductor canal blocks after knee arthroscopy (KA). Methods In this randomized, double-blinded, controlled study, 90 patients scheduled for knee arthroscopy were randomly allocated into three groups to receive adductor canal block after the end of the arthroscopy. The control group received 20 ml bupivacaine 0.5%+2 ml normal saline, the dexamethasone group received 20 ml bupivacaine 0.5%+2 ml dexamethasone (8 mg) and the neostigmine group received 20 ml bupivacaine 0.5%+1 ml neostigmine (500 mcg) +1 ml normal saline. Outcomes: time of first rescue analgesia, sensory blockade duration, total opioid consumption, and visual analog score (VAS). Results Time of first rescue analgesia and Sensory block duration, were longer in dexamethasone and neostigmine groups compared with control group, with no significant difference between dexamethasone and neostigmine groups, however, clinically there was 3 h prolongation in sensory block duration in dexamethasone group. Mean morphine consumption and Visual analog score were lower in dexamethasone and neostigmine groups compared with control group, with no difference between dexamethasone and neostigmine groups, Conclusion Both dexamethasone and neostigmine were effective adjuvants to bupivacaine in ACB with more prolonged postoperative analgesia and less opioid consumption. Though there was no statistically significant difference between both drugs, however, dexamethasone showed some clinical superiority.