Analgesic efficacy of erector spinae plane block versus intrathecal morphine in cesarean section: randomized clinical trial

ABSTRACT

BACKGROUND AND OBJECTIVES  While intrathecal opioids are effective in managing post-cesarean pain, their use is often associated with adverse effects such as nausea, pruritus, and delayed return of bowel function. The erector spinae plane block (ESPB) has emerged as a promising alternative, offering effective analgesia with a more favorable side effect profile. Thus, in this study, the aim was to compare the analgesic efficacy and adverse effects of bilateral parasagittal ESPB with intrathecal morphine (ITM) in patients undergoing elective cesarean sections.

METHODS  A randomized, controlled clinical trial was conducted with 54 pregnant women undergoing elective cesarean sections, allocated into two groups: ITM (n = 27) and ESPB (n = 27). The ITM group received hyperbaric bupivacaine combined with morphine, while the ESPB group received hyperbaric bupivacaine and a bilateral ultrasound-guided 0.25% levobupivacaine block at the T9 level. Pain at rest was assessed using a verbal numerical rating scale (vNRS) at 2, 6, 12, and 24 h postoperatively. Adverse effects, use of supplementary analgesia, time to first bowel movement, and length of hospital stay were also recorded.

RESULTS  There was no significant difference in pain intensity between the groups at any of the assessed time points. However, the ITM group had a significantly higher incidence of pruritus (74.1%), nausea (44.4%), and emesis (22.2%), whereas none of the patients in the ESPB group experienced these adverse effects (p<0.05). The use of supplementary analgesia was higher in the ESPB group, though not statistically significant (25.9% vs. 3.7%). Elimination of flatus occurred earlier in the ESPB group (p=0.001), although the length of stay was similar between groups.

CONCLUSION  ESPB achieved effective analgesia with fewer adverse effects than ITM. These findings support ESPB as a safe, effective, and well-tolerated alternative for post-cesarean analgesia, particularly within multimodal analgesia protocols.

Keywords:
Opioid analgesics; Anesthesia and analgesia; Nerve block; Cesarean section; Pain measurement

HIGHLIGHTS

Although intrathecal opioids are effective in controlling post-cesarean pain, they can be associated with some adverse effects. In this sense, the erector spinae muscle plane block (ESPB) has emerged as a promising analgesic alternative in cesarean sections

The present study aimed to compare the analgesic efficacy and adverse effects of bilateral ESPB with intrathecal morphine (ITM) in patients undergoing elective cesarean sections

ESPB provided effective analgesia, with no statistically significant differences in pain scores or patient satisfaction compared to ITM, and resulted in fewer adverse effects - such as nausea, vomiting, pruritus and delayed bowel function, and did not increase the length of hospital stay