Modified Thoracoabdominal Nerve Block Through the Perichondrial Approach versus Thoracic Epidural Analgesia for Postoperative Analgesia in Robot-Assisted Colorectal Surgery: A Retrospective Cohort Study.

Purpose: Thoracic epidural analgesia is widely considered the gold standard for postoperative pain management in abdominal surgery; however, it is associated with workflow limitations and potential hemodynamic instability. The modified thoracoabdominal nerve block through the perichondrial approach (m-TAPA) has emerged as an alternative technique for abdominal wall analgesia. This study aimed to compare the analgesic efficacy and perioperative impact of epidural analgesia and m-TAPA in patients undergoing robot-assisted colorectal surgery. Patients and methods: This retrospective, single-center, non-randomized cohort study included 45 adult patients who underwent robot-assisted laparoscopic colorectal resection between January and October 2024. Patients received either thoracic epidural analgesia (n = 23) or bilateral single-shot m-TAPA (n = 22), selected at the discretion of the attending anesthesiologist. The primary outcome was postoperative pain intensity assessed using the Numerical Rating Scale (NRS) at 4-hour intervals. Secondary outcomes included intraoperative and postoperative opioid consumption, time from operating room entry to surgical incision, vasopressor use, and analgesia-related complications. Results: Postoperative NRS scores were comparable between groups up to 16 hours after surgery. At 20 and 24 hours postoperatively, pain scores were significantly lower in the epidural group. Intraoperative and postoperative fentanyl consumption was significantly higher in the m-TAPA group (p < 0.01 for both comparisons). The time from operating room entry to surgical incision was significantly shorter in the m-TAPA group (p = 0.035). Postoperative bolus vasopressor therapy was more frequently required in the epidural group (p = 0.0045). The incidence of postoperative nausea and vomiting, atelectasis, neurological complications, urinary retention, and intensive care unit length of stay did not differ significantly between groups. Conclusion: In this small retrospective cohort, m-TAPA provided comparable early postoperative analgesia but was associated with higher opioid consumption compared with epidural analgesia. Given the non-randomized design, small sample size, and differences in analgesic duration between techniques, these findings should be interpreted with caution. m-TAPA may represent a practical alternative in selected patients; however, further prospective studies are required to confirm these findings.