Effect of bupivacaine on pain after tonsillectomy: a randomized clinical trial

Several authors have found that pre-incisional injection of local anaesthetics reduces postoperative pain. In the present double-blind study, comprising 126 inpatients aged 6-42 (mean 19) years, we investigated whether pre-incisional injection of bupivacaine during general anaesthesia reduces the pain experienced after tonsillectomy. The patients were randomized into three treatment groups: 43 patients were injected with 5 ml of bupivacaine (2.5 mg/ml)+ epinephrine (5 microg/ml) solution in both tonsillar fossa, 41 had epinephrine (5 microg/ml) + saline (9 mg/ml) and 42 patients received saline (9 mg/ml) only. Self-assessment of pain during the first postoperative week (repeated measures) was recorded. Use of analgetics, experience of the surgeons, peroperative bleeding and several other clinical parameters were assessed. Analyses of covariance with repeated measures was carried out for each pain score. In general there was no statistical significant difference in pain scores, represented by a visual analogue scale (VAS) between the three treatment groups. However, injection of bupivacaine into the tonsillar fossa seemed to reduce pain shortly after the operation in the age group 19-24 years. Further, females and older patients reported more pain and used more analgetics than males and younger patients. Increasing experience of the surgeon was related to a lower score for baseline pain shortly after the operation. Epinephrine in bupivacaine or saline reduced peroperative bleeding. We conclude that bupivacaine does not provide significant postoperative analgesia after tonsillectomy in an unselected group of patients.