Epidural versus continuous transversus abdominis plane catheter technique for postoperative analgesia after abdominal surgery

Transversus abdominis plane block is an effective postoperative analgesic technique after abdominal surgery, but no study has compared continuous transversus abdominis plane block with continuous epidural analgesia. We designed a randomised controlled trial comparing these techniques for major abdominal surgery. Patients in the epidural group received a bolus of 8 to 15 ml of ropivacaine 0.2% and an infusion of 5 to 15 ml/hour and the transversus abdominis plane block group a bolus dose of 20 ml of ropivacaine 0.375% bilaterally and an infusion of 0.2% ropivacaine 8 ml/hour bilaterally, for three days. Both groups received paracetamol and patient controlled analgesia with fentanyl for three days. Primary outcomes were numerical rating scores for pain (rest and dynamic over 72 hours) and total fentanyl use; complications and satisfaction scores were also noted. The study was terminated early after 42 patients had been randomised (epidural n=19; transversus abdominis plane block n=22; one excluded). No differences were found in regards to point pain scores or scores over time, either immediately postoperatively or in surgical wards; total fentanyl requirement and Likert satisfaction scores were also similar in both groups. In this underpowered study we found comparable results between continuous transversus abdominis plane technique and epidural analgesia in regard to pain, analgesic use and satisfaction after abdominal surgery. To confirm this finding, randomised trials with larger numbers of participants are needed.