Comparison of ultrasound-guided iliohypogastric/ilioinguinal nerve block and transversus abdominis plane block for analgesia after cesarean section: A retrospective propensity match study

Effective and adequate post-operative analgesia for cesarean section is in demand due to increasing rates of cesarean deliveries, and may help promote recovery, ambulation and breastfeeding. Local nerve block has been applied as post-operative analgesia for maternal patients receiving cesarean section; specifically, lateral abdominal transversus abdominis plane block (TAPB) and iliohypogastric/ilioinguinal nerve block (IHINB) under ultrasound guidance have been proven to be effective. The present study aimed to compare the analgesic effect of TAPB and IHINB in maternal females undergoing cesarean section. Propensity-matched females who received cesarean section (n=124) were retrospectively enrolled and divided into the TAPB group (n=62) and the IHINB group (n=62) according to their post-operative analgesia treatment. All of the patients have been given spinal-epidural anesthesia during the operation, while they received either TAPB or IHINB for post-operative analgesia. Demographic and clinical data were collected and compared, including time to first morphine request, cumulative morphine consumption, visual analogue scale (VAS) score and adverse events. Due to propensity matching, there was no significant difference between the two groups in their baseline characteristics (all P>0.05). The log-rank test indicated no significant difference in the Kaplan-Meier curves for the time to first morphine request between the two groups (P=0.575). The VAS score and cumulative morphine consumption at 6 and 12 h was similar between the two groups (all P>0.05). However, these two parameters were significantly lower in the IHINB group at 24 and 48 h (P<0.001). Uni- and multivariate logistic regression analysis indicated that the method of block was not an independent influencing factor regarding postoperative pain relief (P=0.628). There was also no difference between the two groups in adverse events of analgesia (all P>0.05). In conclusion, the present study demonstrated that TAPB and IHINB achieved a comparably satisfactory analgesic effect after cesarean section. However, the analgesic effect of IHINB was better than that of TAPB at the later stages.