External Oblique Intercostal Block (EOICB) for Laparoscopic Cholecystectomy

This single center, prospective, randomised controlled clinical trial is designed to evaluate analgesic efficacy and opioid sparing effect of ultrasound guided paravertebral block (PVB) and external oblique intercostal (EOI) block versus systemic opioid based analgesia in adult patients undergoing elective laparoscopic cholecystectomy under general anesthesia.

Pain after laparoscopic cholecystectomy is often moderate to severe during the first 24 hours , and has somatic and visceral components . Regional approaches that target thoracoabdominal dermatomes and visceral afferents may provide superior analgesia, allow for earlier mobilisation, and reduce opioid-related adverse effects compared with intravenous opioid regimens alone. PVB provides unilateral segmental blockade at thoracic paravertebral level, while the EOI block deposits local anaesthetic in the fascial plane between the external oblique and intercostal muscles, with spread to relevant thoracoabdominal nerves.

In a parallel-group design, participants will be randomly allocated to bilateral thoracic PVB, bilateral EOI block or no truncal block with standard systemic analgesia. All regional blocks will be performed under ultrasound guidance after induction of general anaesthesia. Standardised volumes and concentrations of long-acting local anaesthetic will be used according to institutional practice. The control group will receive patient-controlled intravenous opioid analgesia as part of a multimodal approach.

Standardisation of intraoperative monitoring and technique of general anaesthesia according to departmental protocols will be done for perioperative anaesthetic management. Postoperative pain intensity will be assessed by an 11-point Numerical Rating Scale at specified time points during the first 24 hours. Rescue analgesia will be administered according to a predefined algorithm. The trial's purpose is to compare postoperative opioid use between groups and to investigate differences in pain trajectories and opioid-related adverse events in routine clinical conditions.

Inclusion criteria

• Age between 18 and 65 years
• Scheduled for elective laparoscopic cholecystectomy under general anesthesia
• ASA physical status I-III
• Able to understand the study procedure and provide informed consent

Exclusion criteria

Patient refusal or inability to provide informed consent

Allergy or contraindication to local anesthetics, tramadol, or study medications

Coagulopathy or current anticoagulant therapy

Local infection at the planned block injection site

Severe hepatic or renal impairment

Chronic opioid use or opioid dependence

Neurological or psychiatric disorders affecting pain perception or communication

Pregnancy or breastfeeding

Body mass index (BMI) > 35 kg/m²

Conversion to open cholecystectomy during surgery