Buprenorphine added to levobupivacaine enhances postoperative analgesia of middle interscalene brachial plexus block

The aim of this study was to assess whether addition of epineural buprenorphine prolonged postoperative analgesia of middle interscalene brachial plexus block (MIB) with levobupivacaine. One hundred and fifty consenting adult patients, scheduled for shoulder arthroscopic surgery for a rotator cuff tear under MIB with 29.5 ml of 0.75 % levobupivacaine, were randomized to receive additionally either saline or intramuscular buprenorphine 0.15 mg or epineural buprenorphine 0.15 mg. Onset of sensory and motor blocks, duration of postoperative analgesia, and consumption of postoperative analgesics were compared among the groups. There were significant (P < 0.05) differences in the onset and the duration of the sensory block and in the duration of postoperative analgesia. Duration of both sensory block and postoperative analgesia was longer (P < 0.05) in patients who had received epineural buprenorphine (856.1 +/- A 215.2 and 1,049.7 +/- A 242.2 min) than in patients who had received intramuscular buprenorphine (693.6 +/- A 143.4 and 820.3 +/- A 335.3 min) or saline (488.3 +/- A 137.6 and 637.5 +/- A 72.1 min). Requirement of postoperative rescue analgesics was lower in the epineural buprenorphine group than in the other two groups. Few complications occurred from MIB (< 1 %) and none from buprenorphine. Epineural buprenorphine prolonged postoperative analgesia of MIB more effectively than intramuscular buprenorphine, which suggests that buprenorphine acts at a peripheral nervous system site of action.