Effects of spinal anaesthesia versus epidural anaesthesia for caesarean section on postoperative analgesic consumption and postoperative pain

BACKGROUND AND OBJECTIVE: Regional anaesthesia is commonly used for elective caesarean section. The aim of this study was to investigate whether there is a positive effect of either spinal or epidural anaesthesia on postoperative analgesic requirements and pain relief. METHODS: The analgesic effect of either spinal or epidural induction of perispinal anaesthesia have been compared in 132 women (ASA I or II) scheduled for elective caesarean section, all having epidural catheterization for perioperative anaesthesia and postoperative analgesia. The patients were randomized into two groups. To achieve a sensory block height to the level of the sixth thoracic dermatome, the parturients received isobaric bupivacaine 0.5% and 5 microg sufentanil intrathecally or ropivacaine 0.75% and 10 microg sufentanil epidurally. For postoperative analgesia, all patients used patient-controlled epidural analgesia at identical settings [bolus of ropivacaine 0.133% (11-15 mg according to patient's height), lock-out time 1 h]. Intraoperative and postoperative pain was recorded using a visual analogue pain score as well as analgesic requirements over the first 24 h after surgery. RESULTS: One hundred and twenty-five patients completed the study. There were no differences in patient-controlled epidural analgesic requirements between groups. During surgery, the pain score on a visual analogue scale was more intense with epidural anaesthesia than with spinal anaesthesia (P < 0.05). For the whole 24 h observation period, the area under the curve for pain was lower with spinal anaesthesia (P < 0.0005). At almost all postoperative time points, visual analogue scale scores at rest and during mobilization were lower with spinal anaesthesia (P < 0.05), which was accompanied by less motor blockade and lower frequency of adverse effects. More patients with epidural anaesthesia received supplemental analgesic medication. CONCLUSION: In parturients undergoing elective caesarean section, postoperative use of epidural ropivacaine via patient-controlled epidural analgesia is similar after spinal and epidural anaesthesia. Spinal anaesthesia is, however, accompanied with less postoperative pain, use of additional analgesics and side-effects.