Comparison of Paragastric Nerve Block and Erector Spinae Plane Block on Postoperative Pain After Sleeve Gastrectomy

A Prospective Randomized Controlled Trial Comparing the Effects of Paragastric Nerve Block and Erector Spinae Plane Block on Postoperative Pain Management Following Laparoscopic Sleeve Gastrectomy

Background: Laparoscopic sleeve gastrectomy is one of the most commonly performed bariatric procedures for the treatment of obesity. Despite its minimally invasive nature, patients frequently experience moderate to severe postoperative pain, which may delay mobilization, prolong hospital stay, increase opioid consumption, and reduce patient satisfaction. Effective postoperative pain management is therefore an important component of perioperative care.

Regional analgesia techniques are increasingly used as part of multimodal analgesia protocols to reduce opioid requirements and opioid-related adverse effects. Paragastric nerve block (PGNB) has been reported to provide effective control of visceral pain, nausea, and vomiting after sleeve gastrectomy. Erector spinae plane block (ESPB) is another regional anesthesia technique that has demonstrated efficacy in reducing perioperative opioid consumption in bariatric surgery patients. However, no prospective randomized study has directly compared PGNB and ESPB in patients undergoing sleeve gastrectomy.

This prospective, randomized, controlled clinical trial aims to compare the effects of PGNB, ESPB, and standard analgesia on postoperative pain management following laparoscopic sleeve gastrectomy. Seventy-two adult patients scheduled for elective sleeve gastrectomy will be randomized in a 1:1:1 ratio to receive PGNB, ESPB, or standard multimodal analgesia alone. The primary outcome will be postoperative pain intensity measured using the Visual Analog Scale (VAS) at 1, 6, 12, and 24 hours after surgery. Secondary outcomes include postoperative opioid consumption, intraoperative remifentanil consumption, additional analgesic requirements, time to first analgesic request, postoperative nausea and vomiting, and block-related complications.

Laparoscopic sleeve gastrectomy is one of the most frequently performed bariatric surgical procedures for the treatment of morbid obesity. Although the procedure is minimally invasive, patients commonly experience moderate to severe postoperative pain during the early postoperative period. Inadequate pain control may delay mobilization, prolong hospital stay, increase pulmonary complications, reduce patient satisfaction, and increase opioid consumption, leading to opioid-related adverse effects such as nausea, vomiting, sedation, and respiratory depression.

Regional anesthesia techniques have become an important component of multimodal analgesia protocols aimed at improving postoperative pain control while reducing opioid requirements. Paragastric nerve block (PGNB) is a surgeon-performed regional analgesic technique targeting visceral afferent nerve fibers surrounding the stomach. Previous studies have suggested that PGNB may reduce postoperative pain, opioid consumption, nausea, and vomiting following sleeve gastrectomy. Erector spinae plane block (ESPB) is an ultrasound-guided fascial plane block that has gained popularity in thoracoabdominal surgery because of its ease of application, favorable safety profile, and potential analgesic benefits. ESPB has been shown to reduce perioperative opioid consumption and improve postoperative analgesia in bariatric surgical patients.

Despite the growing use of both techniques, there is limited evidence directly comparing PGNB and ESPB in patients undergoing laparoscopic sleeve gastrectomy. Therefore, the optimal regional analgesic technique for this patient population remains uncertain.

The present study is designed as a prospective, randomized, controlled, parallel-group clinical trial conducted at Atlas University Faculty of Medicine Hospital. Following Institutional Review Board approval and written informed consent, 72 adult patients scheduled for elective laparoscopic sleeve gastrectomy will be enrolled. Eligible participants will be between 18 and 65 years of age, classified as ASA physical status II-III, and meet established bariatric surgery criteria.

Participants will be randomly assigned in a 1:1:1 ratio to one of three study groups:

1. Paragastric Nerve Block (PGNB) Group: Patients will receive intraoperative paragastric nerve block performed by the operating surgeon using 18 mL of 0.5% bupivacaine distributed across predefined paragastric anatomical regions.
2. Erector Spinae Plane Block (ESPB) Group: Patients will receive bilateral ultrasound-guided ESPB at the T6 vertebral level before surgery using 0.25% bupivacaine, with a maximum dose not exceeding 2 mg/kg.
3. Control Group: Patients will receive standard perioperative multimodal analgesia without regional block intervention.

All participants will undergo standardized general anesthesia and multimodal analgesia protocols. Intraoperative remifentanil administration will be titrated according to routine clinical practice.

The primary outcome measure will be postoperative pain intensity assessed using the Visual Analog Scale (VAS) at 1, 6, 12, and 24 hours after surgery.

Secondary outcome measures will include:

• Total postoperative analgesic and opioid consumption during the first 24 hours.
• Additional analgesic requirements.
• Time to first analgesic request.
• Intraoperative remifentanil consumption.
• Incidence of postoperative nausea and vomiting.
• Block-related adverse events and complications, including local anesthetic systemic toxicity, hematoma, or infection.

Postoperative assessments will be performed by investigators blinded to group allocation whenever feasible. Data will be collected during the intraoperative period, post-anesthesia care unit stay, and throughout the first 24 postoperative hours.

The findings of this study are expected to provide evidence regarding the comparative effectiveness and safety of PGNB and ESPB for postoperative pain management following laparoscopic sleeve gastrectomy and may contribute to the optimization of perioperative analgesic strategies in bariatric surgery.

Inclusion Criteria: - Age between 18 and 65 years Scheduled for elective Sleeve Gastrectomy surgery Classified as ASA physical status II-III Body mass index (BMI) ≥30 kg/m² with obesity-related comorbidities or BMI ≥40 kg/m² Willing to participate in the study and has provided written informed consent

Exclusion Criteria:

• Known allergy or hypersensitivity to local anesthetic agents Allergy or contraindication to paracetamol or NSAIDs Coagulopathy or current anticoagulant therapy Infection or skin lesions at the site of block application Chronic pain syndrome Chronic opioid use, opioid dependence, or use of gabapentin/pregabalin Previous upper gastrointestinal surgery Moderate to severe renal impairment (eGFR <60 mL/min/1.73 m²) Moderate to severe liver disease (Child-Pugh B-C or active hepatic disease) Planned additional surgical procedures Inability to assess pain using VAS Refusal to participate in the study