Local anaesthesia for pain relief after laparoscopic cholecystectomy--a systematic review.

Local anaesthetics (LA) are increasingly being used intraoperatively for the prevention of postoperative pain. The efficacy of local anaesthetic infiltration into incision sites has only been shown in patients undergoing inguinal herniorrhaphy. However, in one meta-analysis of the literature, intraperitoneal LA have been shown to be effective for pain relief following laparoscopic cholecystectomy (LC). The present review of the literature was done to summarise current knowledge on the effects of LA following LC. The Medline database was searched via PubMed to identify relevant randomised clinical trials in patients undergoing LC and where LA was used for pain management. The literature was restricted to adults (> 19 years) and humans. Abstracts of all articles were searched to determine if the trial was a comparison between LA and placebo injected intraperitoneally or infiltrated locally, with relevant postoperative data on pain scores, analgesic consumption and side effects. A total of 31 relevant studies were identified from which data could be extracted. Postoperative pain, in general, was mild to moderate after LC, worst at the incision site or intra-abdominally. Five of six studies in which LA were injected locally found beneficial effects on postoperative pain but not analgesic consumption for up to 24 hours postoperatively. When injected intraperitoneally, 14 of 23 studies found a reduction in pain scores in the LA group but only 9 of 21 found a reduction in analgesic consumption. A meta-analysis of only three studies with extractable data found no difference in abdominal pain during 0-24 hours between the LA and placebo groups. Side effects were few but some studies reported toxic plasma concentrations of LA in some patients, although no symptoms of LA toxicity were seen in these patients. In conclusion, LA have some beneficial effects when infiltrated locally and intraperitoneally. Although side effects are rare, the dose of LA should be monitored closely to avoid toxicity. Future studies should be directed towards determining whether the analgesic effects of LA are via peripheral mechanisms or systemic absorption. The explanation for the wide interindividual variation in pain following LC should also be better investigated.