Comparison of the Postoperative Analgesic Effects of the Temperature-responsive Gel Mixed With Local Anesthetics Application and Ultrasound-guided Transversus Abdominis Plane Block in Patients Undergoing Laparoscopic Gastrectomy (TAP-WELPASS)

This study is a single-center, prospective, randomized controlled trial designed to compare two established postoperative analgesic strategies in adult patients undergoing laparoscopic gastrectomy under general anesthesia.

Effective pain control after laparoscopic gastrectomy is essential to promote early recovery, facilitate ambulation, reduce opioid consumption, and improve overall postoperative outcomes. Although minimally invasive techniques reduce surgical trauma, patients frequently experience moderate postoperative pain arising from abdominal wall incisions and trocar insertion sites.

This trial compares two analgesic approaches:

Ultrasound-guided bilateral transversus abdominis plane (TAP) block using 0.2% ropivacaine

Local application of a thermosensitive ropivacaine-poloxamer 407 hydrogel formulation (Welpass®) applied to the surgical site at the end of surgery

A total of 80 patients (age ≥19 years, American Society of Anesthesiologists physical status I-III) scheduled for elective laparoscopic gastrectomy will be enrolled at a single institution. Participants will be randomly assigned in a 1:1 ratio to either the TAP block group (n=40) or the hydrogel group (n=40).

In the TAP block group, 0.2% ropivacaine will be injected bilaterally between the internal oblique and transversus abdominis muscles under ultrasound guidance at the completion of surgery.

In the hydrogel group, a mixture of ropivacaine and poloxamer 407-based gel (Welpass®) will be prepared and applied locally to the surgical site, including the fascial plane and subcutaneous tissue, prior to wound closure.

All patients will receive standardized general anesthesia and postoperative patient-controlled analgesia (PCA) according to institutional protocols.

The primary objective of the study is to compare postoperative pain intensity between the two groups. Pain will be assessed using the Visual Analog Scale (VAS) immediately upon arrival in the post-anesthesia care unit (PACU), just before PACU discharge, and at 12 and 24 hours after surgery.

Secondary outcomes include:

• Total PCA consumption within 48 hours
• Additional analgesic use (total dose and frequency)
• Time to first flatus
• Time to ambulation
• Length of hospital stay
• Incidence of postoperative nausea and vomiting (PONV)

Safety will be evaluated by monitoring adverse events, including signs of local anesthetic systemic toxicity or other serious complications. Both analgesic techniques involve medications and procedures that are widely used in routine clinical practice. The study uses approved drugs within standard dosing ranges and is conducted by experienced clinicians. If a serious adverse event suspected to be related to the intervention occurs, appropriate medical management will be provided immediately, and the Institutional Review Board (IRB) will be notified in accordance with regulatory requirements.

Participants may be withdrawn from the study if they experience a serious adverse reaction related to the intervention, if conversion to open surgery occurs, or if they choose to withdraw consent.

The aim of this study is to determine whether local application of sustained-release ropivacaine hydrogel provides analgesic efficacy comparable or superior to ultrasound-guided TAP block. The findings may help identify an effective and safe postoperative pain management strategy for patients undergoing laparoscopic gastrectomy and contribute to optimizing multimodal analgesia protocols in minimally invasive gastric surgery.

Study Overview

• Status: Not yet recruiting
• Conditions: Postoperative Pain; Gastric Cancer
• Intervention / Treatment: Procedure: Ultrasound-guided Transversus Abdominis Plane (TAP) Block; Drug: Ropivacaine-Poloxamer 407 Hydrogel (Welpass®)

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Gyeong Jo Byun, MD; Phone Number: 82-10-5663-1713; Email: byeongj@pusan.ac.kr

Study Locations

• South Korea
  • Gyeongsamnamdo
    • Yangsan, Gyeongsamnamdo, South Korea, 50612
      • Yangsan Pusan National University Hospital
      • Contact: Gyeongjo Byun, MD; Phone Number: 82-10-5663-1713; Email: byeongj@pusan.ac.kr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults aged 19 years or older undergoing laparoscopic gastrectomy under general anesthesia
• American Society of Anesthesiologists (ASA) physical status I-III

Exclusion Criteria:

• Known hypersensitivity or allergy to local anesthetics
• Presence of autoimmune disease or dermatologic conditions such as keloids
• Conversion from laparoscopic surgery to open surgery
• Pregnant women
• Chronic opioid use for persistent pain
• Inability to communicate effectively, making pain assessment difficult
• Refusal to participate in the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: TAP Block Group; Participants receive bilateral ultrasound-guided transversus abdominis plane (TAP) block with 0.2% ropivacaine at the completion of laparoscopic gastrectomy. Standardized general anesthesia and postoperative patient-controlled analgesia (PCA) are provided	Procedure: Ultrasound-guided Transversus Abdominis Plane (TAP) Block; Bilateral ultrasound-guided injection of 0.2% ropivacaine between the internal oblique and transversus abdominis muscles at the end of surgery
Experimental: Ropivacaine-Poloxamer Hydrogel Group; Participants receive local application of ropivacaine-poloxamer 407 thermosensitive hydrogel (Welpass®) at the surgical site following laparoscopic gastrectomy. Standardized general anesthesia and postoperative PCA are provided	Drug: Ropivacaine-Poloxamer 407 Hydrogel (Welpass®); Local application of a thermosensitive hydrogel containing ropivacaine and poloxamer 407 to the fascial and subcutaneous layers at the surgical site prior to wound closure

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative Pain Intensity	Postoperative pain intensity measured using the Visual Analog Scale (VAS, 0-10) immediately upon arrival in the post-anesthesia care unit (PACU) and just before PACU discharge. The VAS ranges from 0 (no pain) to 10 (worst imaginable pain). Mean pain scores will be compared between the two groups	postoperative period(immediately upon arrival in PACU, at PACU discharge, 12,24 hours after surgery)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Patient-Controlled Analgesia (PCA) Consumption	Total cumulative dose of intravenous patient-controlled analgesia administered during the first 48 hours after surgery.	48 hours postoperatively
Total Rescue Analgesic Dose	Total cumulative dose of additional rescue analgesics administered within 48 hours after surgery.	48 hours postoperatively
Number of Rescue Analgesic Administrations	Total number of additional rescue analgesic administrations within 48 hours after surgery.	48 hours postoperatively
Number of PONV Episodes	Total number of postoperative nausea and vomiting episodes occurring within 48 hours after surgery.	48 hours postoperatively
Time to First Flatus	Time from the end of surgery to the first passage of flatus, measured in hours.	From the end of surgery until the first documented passage of flatus, assessed up to 7 days postoperatively
Time to First Ambulation	Time from the end of surgery to first ambulation, measured in hours.	From end of surgery to first ambulation, assessed up to 7 postoperative days
Length of Postoperative Hospital Stay	Duration of hospitalization from the date of surgery to the date of discharge, measured in days.	From date of surgery to date of discharge, assessed up to 30 days postoperatively

Collaborators and Investigators

• Sponsor: Gyeong-Jo Byeon, MD, PhD

Study record dates

Study Major Dates

• Study Start (Estimated): February 12, 2026
• Primary Completion (Estimated): February 11, 2027
• Study Completion (Estimated): February 11, 2027

Study Registration Dates

• First Submitted: February 20, 2026
• First Submitted That Met QC Criteria: March 2, 2026
• First Posted (Actual): March 5, 2026

Study Record Updates

• Last Update Posted (Actual): March 5, 2026
• Last Update Submitted That Met QC Criteria: March 2, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Neoplasms by Site; Neoplasms; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Stomach Diseases; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Stomach Neoplasms; Digestive System and Oral Physiological Phenomena; Dentistry; Dental Physiological Phenomena; Dental Occlusion
• Other Study ID Numbers: WELPASS-TAP; IRB 21-2026-002 (Other Identifier: PNUYH IRB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Individual participant data will not be shared due to institutional policies and restrictions outlined in the informed consent process. The study is a single-center clinical trial, and no plans for public data repository submission have been established

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No