A comparison of pre- and postoperative tonsillar infiltration with bupivacaine on pain after tonsillectomy. A pre-emptive effect?

Thirty-five healthy patients aged 15-36 years scheduled for bilateral tonsillectomy were randomly allocated to receive the following treatments: tonsillar infiltration with 0.25% bupivacaine 5 min before surgical incision (n = 12); identical tonsillar infiltration administered after both tonsils had been surgically removed (n = 12); infiltration with isotonic saline 5 min before the operation (n = 11). There were no significant differences between groups in pain scores (VAS) at rest or during drinking of 100 ml of water as measured at 4 h postoperatively or on the 1st, 2nd, 3rd and 8th postoperative days. Four, five and three patients in the pre-operative bupivacaine, postoperative bupivacaine, and saline groups, respectively, received one dose of 0.1 mg.kg-1 morphine intravenously (p = 0.76). Cumulative acetylsalicylic acid requirements during the observation period were not significantly different between groups (p = 0.78). These results suggest that pre-operative infiltration of 0.25% bupivacaine has no beneficial pre-emptive analgesic action compared to both an identical treatment administered after tonsillectomy and a placebo.