External Oblique Intercostal Plane Block for Postoperative Analgesia After Major Upper Abdominal Surgery

Jun Zhang

Status: Not yet enrolling

Conditions: Postoperative Pain; Abdominal Surgery

Treatments: Other: Standard multimodal analgesia; Procedure: External Oblique Intercostal Plane Block

Study type: Interventional

Funder types: Other

Identifiers

NCT07331441

2512335-12

Details and patient eligibility

About

Postoperative pain after laparoscopic major upper abdominal surgery (e.g., gastric, hepatic, gallbladder, pancreatic surgery) is often severe, and inadequate analgesia may lead to increased opioid use, opioid dependence, and poor functional recovery. Current analgesic techniques such as neuraxial block have safety concerns (e.g., hypotension, neurological injury), while transversus abdominis plane (TAP) block is ineffective for blocking the lateral cutaneous branches of intercostal nerves in the upper abdomen. The External Oblique Intercostal Plane Block (EOIB) is a novel regional block technique that has shown promise in reducing postoperative opioids and pain in small-scale studies, but evidence for its use in major upper abdominal surgery is limited. This randomized controlled trial (RCT) aims to evaluate the analgesic efficacy and safety of bilateral EOIB combined with standard multimodal analgesia versus standard multimodal analgesia alone in patients undergoing elective laparoscopic major upper abdominal surgery. The primary outcome is the total postoperative opioid consumption (measured as Morphine Milligram Equivalents, MME) within 24 hours. Secondary and additional outcomes include pain scores (Verbal Rating Scale, VRS), recovery quality (QoR-15 scale), incidence of adverse events, and hospital stay.

Full description

Postoperative pain after major upper abdominal surgery is common and may delay recovery and increase opioid-related adverse effects. The External Oblique Intercostal Plane Block (EOIB) is a novel fascial plane block intended to improve analgesia for upper abdominal incisions.

This study is a prospective, single-center, randomized, assessor-blinded controlled trial in adults (18-85 years, ASA I-III) scheduled for elective major upper abdominal laparoscopic-assisted surgery (e.g., gastric, hepatic, gallbladder, pancreatic procedures) with expected operative time ≥2 hours and planned use of IV patient-controlled analgesia (PCA). Participants will be randomized 1:1 using a computer-generated, variable block-size sequence with allocation concealment via opaque sealed envelopes. The block-performing anesthesiologist will not collect outcomes; outcome assessors will be blinded to group assignment.

After induction of general anesthesia and before surgical incision, patients in the intervention group will receive ultrasound-guided bilateral EOIB at the 6th rib level using an in-plane technique; 15 mL per side of a mixture of 0.75% ropivacaine and normal saline will be injected. Control participants will receive no regional block. All participants will receive standardized multimodal analgesia including IV PCA, antiemetic prophylaxis (dexamethasone 5 mg; ondansetron as needed), and NSAID use per ERAS practice.

The primary endpoint is total opioid consumption during the first 24 hours after surgery, expressed as IV morphine milligram equivalents (MME), including PCA and rescue opioids. Secondary outcomes include postoperative pain scores (0-10 verbal rating scale) at prespecified time points (including 24, 48, and 72 hours; at rest and with activity as applicable), quality of recovery (QoR-15 at 24/48/72 hours), opioid consumption at 24-48 hours, postoperative nausea and vomiting within 72 hours, intraoperative hemodynamic events, time to first flatus, and postoperative length of stay.

Enrollment: 78 estimated patients

Sex: All

Ages: 18 to 85 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Obtain written informed consent from participants or their legal representatives
• Age between 18 and 85 years
• American Society of Anesthesiologists (ASA) physical status classification I-III
• Scheduled for elective laparoscopic major upper abdominal surgery (e.g., gastric, hepatic, gallbladder, pancreatic surgery)
• Expected surgical duration ≥ 2 hours
• Ability to use the intravenous patient-controlled analgesia (IV PCA) system

Exclusion criteria

• Hepatic disease (liver enzyme levels ≥ 2× the upper limit of normal)
• Renal disease (serum creatinine levels ≥ 2× the upper limit of normal)
• Allergy to local anesthetics or known study-related drugs
• Pregnancy or lactation
• Low surgical incision site (not involving the upper abdominal wall innervated by T6-T10 nerves)
• Coagulopathy or current use of anticoagulant medications
• Opioid use for more than 2 weeks in the past 6 months

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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78 participants in 2 patient groups

EOIB Block

Experimental group

Description:

Participants receive ultrasound-guided bilateral External Oblique Intercostal Plane Block (EOIB) after induction of general anesthesia and before surgical incision, using ropivacaine (15 mL per side), in addition to standard multimodal analgesia (including IV PCA and ERAS-based non-opioid analgesics).

Treatment:

Procedure: External Oblique Intercostal Plane Block

Usual Analgesia

Sham Comparator group

Description:

Participants receive standard multimodal analgesia without any regional block. Analgesia includes IV patient-controlled analgesia (PCA) and other non-opioid analgesics per the institutional ERAS protocol.

Treatment:

Other: Standard multimodal analgesia