Authors: Tong C et al.
Anesthesiology, December 29, 2025, 10.1097/ALN.0000000000005846
This randomized controlled trial evaluated the effectiveness of the ultrasound-guided external oblique intercostal (EOI) plane block using ropivacaine for postoperative analgesia in patients undergoing open hepatectomy. The EOI plane block is a relatively new regional anesthesia technique designed to provide analgesia to the upper abdominal wall by depositing local anesthetic in the fascial plane between the external oblique muscle and the intercostal muscles.
Effective postoperative analgesia following open hepatectomy can be challenging. Thoracic epidural analgesia and paravertebral blocks are commonly used but may be contraindicated in patients with coagulopathy or other risk factors frequently present in liver surgery patients. The EOI block has emerged as a potential alternative that may provide effective analgesia with a lower risk of complications.
This study enrolled 70 adult patients scheduled for elective open hepatectomy at Zhongshan Hospital of Fudan University in Shanghai, China. Patients were randomly assigned in a 1:1 ratio to receive either an ultrasound-guided EOI plane block with 30 ml of 0.375% ropivacaine or an equivalent volume of normal saline. All patients received standard patient-controlled intravenous analgesia (PCIA) postoperatively.
The primary outcome measured was opioid consumption during the first 24 hours after surgery, expressed in intravenous morphine equivalents. Secondary outcomes included opioid consumption at additional postoperative time points, pain scores at rest and during coughing, intraoperative opioid use, time to first rescue analgesia, postoperative complications, recovery quality scores, hospital length of stay, and incidence of chronic pain at three months.
The results demonstrated that patients receiving the EOI block required significantly less opioid medication after surgery. At 24 hours postoperatively, opioid consumption in the EOI group was significantly lower compared with the control group. The reduction in opioid requirements became even more pronounced at later time points, including 36 and 48 hours after surgery.
Patients in the EOI block group also required less intraoperative fentanyl during the surgical procedure. Additionally, they reported lower pain scores at rest and experienced a longer interval before needing their first rescue analgesic medication.
Pain scores during coughing, however, were not significantly different between the two groups. Similarly, there were no significant differences in overall recovery quality scores, hospital length of stay, or the incidence of chronic postoperative pain at three months.
Importantly, no complications related to the EOI plane block were reported in the study, supporting the safety of the technique in this patient population.
Dermatomal assessment after the block showed effective sensory coverage primarily in the T6 to T8 dermatomes, with excellent coverage extending toward the T5 midline region and occasional spread to adjacent dermatomes such as T4, T9, and T10. This distribution corresponds well with the surgical incision sites typically involved in open hepatectomy.
Overall, the study suggests that the ultrasound-guided EOI plane block can provide meaningful opioid-sparing analgesia for patients undergoing open liver surgery. While it does not replace epidural analgesia in all settings, it may serve as an effective alternative when neuraxial techniques are contraindicated.
What You Should Know
The external oblique intercostal plane block is a newer regional anesthesia technique targeting upper abdominal wall nerves.
In this randomized controlled trial, patients receiving the EOI block required significantly less opioid medication after open hepatectomy.
The block reduced both intraoperative fentanyl requirements and postoperative opioid consumption.
Patients receiving the block reported lower pain scores at rest and experienced a longer time before needing rescue analgesia.
No block-related complications were observed, supporting the safety of the technique.
Key Points
The EOI plane block reduced opioid consumption at 24, 36, and 48 hours after open hepatectomy.
Patients receiving the block required less intraoperative fentanyl.
Resting pain scores were lower in the EOI block group.
Time to first rescue analgesia was longer with the block.
Pain during coughing, recovery quality scores, hospital stay, and chronic pain rates were similar between groups.
No complications related to the EOI block were reported.
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