Caesarean section wound infiltration with local anaesthesia for postoperative pain relief - any benefit?

Delivery by caesarean section (CS) is becoming more frequent. Childbirth is an emotion-filled event, and the mother needs to bond with her baby as early as possible. Any intervention that leads to improvement in pain relief is worthy of investigation. Local anaesthetics have been employed as an adjunct to other methods of postoperative pain relief, but reports on the effectiveness of this strategy are conflicting. This review attempted to assess the effects of local anaesthetic agent wound infiltration and/or abdominal nerve blocks on pain after CS and the mother's well-being and interaction with her baby. Methods. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (April 2009).The selection criteria were randomised controlled trials of local analgesia during CS to reduce pain afterwards. Twenty studies (1 150 women) were included. Results. Women who had wound infiltration after CS performed under regional analgesia had a decrease in morphine consumption at 24 hours compared with placebo (morphine dose -1.70 mg; 95% confidence interval (CI) -2.75 to -0.94). Women who had wound infiltration and peritoneal spraying with local anaesthetic after CS under general anaesthesia (1 study, 100 participants) had a reduced need for opioid rescue (risk ratio (RR) 0.51; 95% CI 0.38 to 0.69). The numerical pain score (0 -10) within the first hour was also reduced (mean difference (MD) -1.46; 95% CI -2.60 to -0.32). Women with regional analgesia who had local anaesthetic and non-steroidal anti-inflammatory cocktail wound infiltration consumed less morphine (1 study, 60 participants; MD -7.40 mg; 95% CI -9.58 to -5.22) compared with those who had local anaesthetic control. Women who had regional analgesia with abdominal nerve blocks had decreased opioid consumption (4 studies, 175 participants; MD -25.80 mg; 95% CI -50.39 to -5.37). For outcome in terms of the visual analogue pain score (0 - 10) over 24 hours, no advantage was demonstrated in the single study of 50 participants who had wound infiltration with a mixture of local analgesia and narcotics versus local analgesia. Conclusions. Local anaesthetic infiltration and abdominal nerve blocks as adjuncts to regional analgesia and general anaesthesia are of benefit in CS by reducing opioid consumption. Non-steroidal anti-inflammatory drugs may provide additional pain relief.