Clinical Efficacy of Single- vs Dual-Level Transversus Abdominis Plane Block for Lower Segment Cesarean Section: A Prospective, Randomized, Controlled Study.

Objective: Transversus abdominis plane block (TAPB) has been widely used for lower-segment cesarean sections (CS). However, traditional single-level TAPB may not provide sufficient analgesia for parturients. This study aimed to validate whether dual-level TAPB could offer more extensive blocking and better clinical outcomes.

Methods: A total of 114 full-term parturients undergoing lower-segment CS were included in this prospective, randomized, controlled study. Subjects were randomly assigned to receive either single-level (group SL) or dual-level (group DL) TAPB. Dual-level TAPB was performed at the umbilical level and the level above the anterior superior iliac spine, while single-level was performed only at the umbilical level. The primary outcome was the proportion of the abdomen successfully blocked 20 minutes after TAPB.

Results: Twenty minutes after TAPB, dual-level TAPB resulted in a more extensive cutaneous sensory block compared to single-level TAPB. The difference in the proportion of successfully blocked zones was statistically significant, with 46.9% (43.8%, 53.1%) in group SL versus 71.9% (62.5%, 75.0%) in group DL, p < 0.001. Notably, the proportion of parturients with the "surgical area" completely blocked was significantly higher in group DL (94.7%) than in group SL (82.5%) (p = 0.039). Compared to Group SL, the first request for postoperative analgesia was delayed in Group DL by 2.5 hours.

Conclusion: Compared to traditional single-level TAPB, dual-level TAPB produced more extensive cutaneous sensory block and better postoperative analgesia effects.