Background and Goal of Study: Spinal morphine is an effective analgesic technique for analgesia after cesarean delivery (CD) , but it is punctuated with side effects. Recently, the transversus abdominis plane (TAP) block has been studied for analgesia after CD and was effective compared to placebo . The purpose of this study is to compare the analgesic efficacy of TAP block to spinal morphine after CD.
Materials and Methods: In this prospective, double-blind study, sixty women undergoing elective CD were randomized to undergo either subarachnoid morphine (group SAM; n = 30) or TAP block (group TAP; n = 30). Patients received bupivacaine spinal anesthesia combined with morphine 0.1 mg in group SAM and received saline in group TAP. At the end of surgery, bilateral TAP block was performed using saline in group SAM or using bupivacaine 0.25% in group TAP with 20 mL on each side. Postoperative analgesia for the first 48 hours consisted of scheduled oral paracetamol and rectal ketoprofen; IV nefopam were administered up on patient request. The primary outcome was the difference in visual analog scale pain scores at rest and on movement during the first 48 postoperative hours. Other outcomes assessed were first analgesic request, analgesic consumption, maternal satisfaction, and incidence of adverse effects.
Results and Discussion: The demographic characteristics were similar in both groups. The mean visual analog scale pain scores at rest and on movement until 48 postoperative hours were not different between the 2 groups. Median (range) time to first analgesic request was similar in both groups 24 (12-48) hours in group SAM versus 24 (2-48) hours in group TAP; (P>0.05). Median (range) of nefopam doses received in the first 48 hours was 40 (0-80) mg in group SAM versus 50 (0-80) mg in group TAP (P>0,05). The incidence of nausea and vomiting was significantly higher in group SAM than in group TAP (50% versus 15%; P=0.02 and 33% versus 3%; P=0.03 respectively). More patients developed pruritus in group SAM than in group TAP (40% versus 3%; P=0,01). There were no complications associated with the performance of the block.
Conclusion(s): As part of a multimodal analgesic regimen, the TAP block provided equivalent analgesic efficacy than spinal morphine up to 48 postoperative hours after CD, with fewer side effects.
 Anesthesiology 1999; 91: 1919-27
 Anesth Analg 2008; 106: 186 -91