A Randomized Controlled Trial Comparing Erector Spinae Plane and Transversus Abdominis Plane Blocks for Postoperative Analgesia after Elective Caesarean Section

Background Peripheral abdominal nerve blocks contribute to multimodal postoperative analgesia that enhances early recovery after caesarean sections. The transversus abdominis plane (TAP) block is an established technique that offers somatic abdominal analgesia. The erector spinae plane (ESP) block is a novel fascial plane block that may offer additional visceral analgesic effects. This study aimed to compare the postoperative analgesic efficacy of bilateral ultrasound-guided ESP blocks to TAP blocks in women undergoing caesarean sections under spinal anaesthesia. Methods Sixty-six ASA grade 1-3 (≥18 years) patients undergoing elective caesarean section under spinal anaesthesia were randomly allocated to receive either ESP blocks at the T9 vertebral level ( n =33) or TAP blocks ( n =33). The primary outcome measure was 24-hour cumulative morphine consumption. The secondary outcomes included the time taken to perform blocks, numeric rating scale (NRS) pain scores at 6- and 24-hours, effect of pain on activities of daily living (ADLs) and care for the newborn, time to first analgesic request, severity of opioid-related side effects, and patient satisfaction. Results There was no statistically significant difference in mean (SD) 24-hour cumulative morphine consumption between the ESP blocks and TAP blocks: 27 mg (14) vs 32 mg (15) (p=0.185). ESP blocks took longer to perform: 10.7 minutes (2.2) vs 9.0 minutes (2.5) (p<0.01). There were no significant differences in the other secondary outcomes. Conclusion ESP blocks did not significantly reduce postoperative analgesic requirements compared to TAP blocks after caesarean section under spinal anaesthesia. The ESP block did not demonstrate significant additional visceral analgesic effects. Trial Registration South African National Clinical Trial Registry (DOH-27-102022-5278), Pan African Clinical Trials Registry (PACTR202301645957324)