This prospective, randomized, double-blind study compares the analgesic efficacy of ultrasound-guided erector spinae plane (ESP) block and subcostal transversus abdominis plane (TAP) block in patients undergoing laparoscopic cholecystectomy. The primary outcome is 24-hour postoperative opioid consumption. Secondary outcomes include postoperative pain scores, time to first analgesic request, shoulder pain, postoperative nausea and vomiting, and block-related complications.

Postoperative pain remains a significant clinical concern after laparoscopic cholecystectomy despite the minimally invasive nature of the procedure. Inadequate analgesia may delay recovery, increase opioid consumption, and negatively affect patient satisfaction. Regional anesthesia techniques are increasingly incorporated into multimodal analgesia protocols to improve postoperative outcomes and reduce opioid requirements.

The erector spinae plane (ESP) block and the subcostal transversus abdominis plane (TAP) block are ultrasound-guided fascial plane blocks commonly used for abdominal surgery. While both techniques have demonstrated analgesic benefits, their comparative effectiveness in laparoscopic cholecystectomy remains uncertain. In particular, differences in visceral pain control, opioid-sparing effect, and shoulder pain incidence require further investigation.

This study is designed as a prospective, randomized, double-blind, parallel-group, clinical trial conducted at two tertiary care hospitals in Turkey. Eligible adult patients scheduled for elective laparoscopic cholecystectomy under general anesthesia will be randomly assigned to receive either bilateral ESP block or bilateral subcostal TAP block after induction of anesthesia. Standardized anesthesia and postoperative multimodal analgesia protocols will be applied in both groups to ensure comparability between centers.

The primary outcome measure is total opioid consumption within the first 24 postoperative hours, expressed as morphine equivalent dose. Secondary outcome measures include postoperative pain scores assessed using the Numerical Rating Scale (NRS), time to first analgesic request, incidence of shoulder pain, postoperative nausea and vomiting, and block-related complications.

Randomization will be performed using a computer-generated sequence, with allocation concealment ensured. Patients and postoperative outcome assessors will be blinded to group assignment. Data will be prospectively recorded and analyzed according to a predefined statistical analysis plan.

The findings of this study are expected to provide evidence-based guidance for optimizing regional analgesia strategies in laparoscopic cholecystectomy.

Inclusion Criteria:

Adults aged 18 years and older

Scheduled for elective laparoscopic cholecystectomy under general anesthesia

American Society of Anesthesiologists (ASA) physical status I-III

Ability to understand the study protocol and provide written informed consent -

Exclusion Criteria:Refusal to participate

Known allergy or contraindication to local anesthetic agents

Coagulopathy or anticoagulant therapy contraindicating regional anesthesia

Infection at the planned injection site

Body mass index (BMI) > 35 kg/m²

Chronic opioid use or opioid dependence

Chronic pain syndromes requiring regular analgesic treatment

Severe hepatic, renal, or cardiac dysfunction

Pregnancy or breastfeeding

Inability to communicate or assess pain using the Numerical Rating Scale (NRS)

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Patients and postoperative outcome assessors will be blinded to group allocation. The regional block will be performed after induction of general anesthesia to maintain participant blinding. Postoperative pain assessments and data collection will be conducted by investigators who are unaware of the assigned intervention. The anesthesiologist performing the block will not be involved in postoperative outcome assessment.