Optimal Patient Positioning for Erector Spinae Plane Block in Laparoscopic Cholecystectomy:

Erector spinae plane (ESP) block is a relatively recent regional anesthesia technique performed under ultrasound guidance, widely used for managing acute postoperative pain. While the ESP block is known for its safety, simplicity, and versatility, there is limited evidence regarding the influence of patient positioning on its clinical effectiveness and technical performance.

This prospective, randomized, single-blind study investigates the impact of administering bilateral ESP block at the T7 vertebral level in three different patient positions: lateral decubitus, prone, and sitting. The study includes adult patients (aged 18-65, ASA I-II) undergoing elective laparoscopic cholecystectomy under general anesthesia.

Primary outcomes include postoperative pain scores (VAS and NRS). Secondary outcomes include total rescue analgesic consumption (tramadol), time to first analgesic requirement, patient satisfaction scores (Likert scale), and measurement of the skin-to-block site distance across different positions. Data will be collected at defined intervals up to 24 hours postoperatively.

The findings are expected to inform clinicians on the optimal patient positioning for ESP block to enhance block efficacy and patient comfort during laparoscopic abdominal surgery.

• Erector Spinae Plane (ESP) Block (Procedure), also known as Ultrasound-guided ESP block: Ultrasound-guided bilateral erector spinae plane (ESP) block performed at the T7 vertebral level. The intervention will be applied in three different patient positions-lateral, prone, or sitting-prior to laparoscopic cholecystectomy.

Primary outcomes

• Postoperative Pain Score (VAS) [0, 2, 4, 6, 12, and 24 hours postoperatively]: Pain intensity will be assessed using the Visual Analog Scale (VAS, 0-10) at multiple time points following laparoscopic cholecystectomy. The goal is to compare postoperative pain scores between patient groups receiving ESP block in lateral, prone, or sitting positions.

Secondary outcomes

• Total Postoperative Analgesic Consumption [First 24 hours after surgery]: The cumulative dose (mg) of tramadol administered as rescue analgesia within the first 24 hours postoperatively will be recorded for each group.
• Time to First Analgesic Request [Within 24 hours postoperatively]: The duration (in minutes) between the end of surgery and the patient's first request for additional analgesia.
• Patient Satisfaction Score [24 hours postoperatively]: Patient satisfaction will be assessed at 24 hours postoperatively using a 5-point Likert scale (1 = very dissatisfied, 5 = very satisfied).
• Skin-to-Target Distance [During preoperative ESP block procedure]: The distance (in millimeters) from the skin to the ESP block site will be measured via ultrasound at the T7 level in each patient position to determine anatomical variation.

Sex: All, ages: 18 Years to 65 Years

Inclusion Criteria:

* Age between 18 and 65 years
* Scheduled for elective laparoscopic cholecystectomy
* ASA physical status I-II
* Ability to understand and provide written informed consent

Exclusion Criteria:

* Allergy to local anesthetics
* History of chronic opioid use or substance abuse
* Coagulopathy or current anticoagulant therapy
* Local infection at the block site
* Severe spinal deformities or scoliosis
* BMI > 35 kg/m²
* Pregnancy or breastfeeding
* Refusal to participate in the study

• Veli F Pehlivan, Asiss Prof, Principal investigator, Harran University Faculty of Medicine, Department of Anesthesiology