Buprenorphine with bupivacaine for intraoral nerve blocks to provide postoperative analgesia in outpatients after minor oral surgery

Abstract

Purpose: The demonstration that opioid receptors exist in the peripheral nervous system offers the possibility of providing postoperative analgesia in the ambulatory surgical patient. Over the previous decade, many investigators have studied this approach and have compared the efficacy of various opioids added to the local anesthetic near the brachial plexus; and it appears from several of these studies that buprenorphine provides the longest duration of analgesia, the most important parameter of postoperative analgesia in outpatients. One of these studies indicated that the agonist-antagonist, buprenorphine, added to bupivacaine provided a longer period of postoperative analgesia than the traditional opiates, but none of the studies was performed in patients undergoing minor oral surgery to check the efficacy of buprenorphine to provide postoperative analgesia in dental patients. The present study was undertaken to ascertain the efficacy of buprenorphine in providing prolonged postoperative analgesia when added to 0.5% bupivacaine with epinephrine 1:200,000.

Patients and methods: Fifty healthy, consenting adult patients scheduled for upper extremity surgery were enrolled in the study. Patients were assigned randomly to 1 of 2 equal groups based on the agents used for the blocks. Patients in group I received 40 mL of a local anesthetic alone, and those in group II received the same local anesthetic plus buprenorphine 0.3 mg. The study was kept double-blind by having one dentist prepare the solutions, a second dentist perform the blocks, and a third dentist monitor the anesthesia and analgesia thereafter, up to and including the time of the first request for an analgesic medication. The data were reported as means +/- standard errors of the mean, and differences between groups were determined using t test. A P value less than .01 was considered statistically significant.

Results: The mean duration of postoperative pain relief after injection of the local anesthetic alone was 8.34 +/- 0.11 hours compared with 28.18 +/- 1.02 hours after buprenorphine was added, a difference that was statistically (and clinically) significant (P < .001).

Conclusion: The addition of buprenorphine to the local anesthetic used for intraoral nerve blocks in the present study provided a 3-fold increase in the duration of postoperative analgesia, with complete analgesia persisting 30 hours beyond the duration provided by the local anesthetic alone in 75% of patients. This practice can be of particular benefit to patients undergoing minor oral surgery by providing prolonged analgesia after discharge from the hospital.