Buprenorphine Enhances and Prolongs the Postoperative Analgesic Effect of Bupivacaine in Patients Receiving Infragluteal Sciatic Nerve Block

Abstract

Background Results from previous studies have shown favorable effects from the addition of buprenorphine to local anesthetics used for interscalene or axillary perivascular brachial plexus blocks. The main objective of the current study was to determine whether addition of buprenorphine could enhance bupivacaine analgesia after infragluteal sciatic nerve block. Methods One hundred and three consenting adult patients for elective foot and ankle outpatient surgeries were prospectively assigned randomly, in double-blind fashion, to one of three groups. Group 1 received 0.5% bupivacaine with epinephrine 1:200,000 for infragluteal sciatic block plus 1 ml normal saline intramuscularly. Group 2 received bupivacaine sciatic block along with intramuscular buprenorphine (0.3 mg). Group 3 received bupivacaine plus buprenorphine for infragluteal sciatic block and 1 ml normal saline intramuscularly. Results Although patients receiving buprenorphine either for sciatic block or intramuscularly had less pain in the postanesthesia care unit compared with patients receiving only bupivacaine, the individual pair-wise comparison of the analysis of variance model showed no statistical difference. However, only buprenorphine added to bupivacaine for sciatic block prolonged postoperative analgesia. Patients receiving a combination of buprenorphine and bupivacaine for sciatic block had lower numeric rating pain scores and received less opioid medication at home than patients in the other two groups. Conclusions The results show that buprenorphine may enhance and prolong the analgesic effect of bupivacaine when used for sciatic nerve blocks in patients undergoing foot and ankle surgery under general anesthesia but does not do so to the extent shown in previous studies using brachial plexus models with mepivacaine and tetracaine.