Gastric outlet obstruction (GOO) refers to mechanical blockage at the pylorus or duodenum, most commonly caused by unresectable malignancies of the stomach, duodenum, or pancreas. At the time of diagnosis, the majority of lesions are no longer amenable to curative resection, and median survival ranges from only 11.3 to 21.3 weeks. Throughout the disease course, patients develop nausea, vomiting, and severe malnutrition, which markedly impair quality of life. Current strategies to relieve obstruction include endoscopic stent placement and surgical gastrojejunostomy; however, each is associated with distinct drawbacks, such as stent occlusion, prolonged operative times, and high complication rates.

Endoscopic ultrasound-guided gastroenterostomy (EUS-GE) is a minimally invasive technique in which a gastric-jejunal anastomosis is created under real-time EUS guidance, bypassing the obstructed segment and establishing a gastrojejunal shortcut. Compared with conventional surgery or endoscopic luminal stenting, EUS-GE offers reduced procedural trauma and lower recurrence rates, providing GOO patients with an additional, less-invasive therapeutic option.

Three main EUS-GE approaches have been described: the direct method, the balloon-assisted method, and the double-balloon-assisted method. The direct method requires large volumes of water instillation, posing hemodynamic risks in patients with cardiovascular or cerebrovascular disease. The double-balloon technique relies on expensive, specialized devices that have not yet been widely adopted. The conventional balloon-assisted method demands needle puncture of a partially inflated balloon, which compromises stability and can displace the target jejunum away from the gastric wall. All three techniques are technically demanding, limiting their broad clinical dissemination.

The investigators therefore designed and previously reported a dedicated single-balloon-assisted device specifically for EUS-GE. This novel system aims to shorten procedure time, reduce intraprocedural water volume, and enhance procedural safety. The present prospective, multicenter, randomized controlled trial was undertaken to validate the clinical efficacy and safety of this new single-balloon-assisted technique compared with the conventional direct water-injection method.

This multicenter, single-blind, RCT is designed to enroll 272 patients across five high-volume tertiary referral centers in China. The study is planned to commence in July 2025 and continue until the final patient completed 12 months of follow-up or passed away. The primary outcome is the operation duration. Secondary outcomes are technical success rate, clinical success rate, intraoperative water injection volume, quality of life assessment, length of hospital stay, and incidence of adverse events (AEs).

Inclusion Criteria:

• Age ranges from 18 to 80 years old
• GOO patients caused by all reasons (including benign diseases such as ulcers or malignant tumors)
• Not suitable for or cannot tolerate surgical operations and endoscopic intestinal stent implantation
• There are no absolute contraindications for EUS-GE
• Signed informed consents

Exclusion Criteria:

• Pregnant and lactating women
• Unable or refused to provide informed consents
• Patients with cognitive impairment, aphasia, mental disorders, or other conditions that may affect the patient's cooperation
• Patients with endoscopic contraindications, anesthesia contraindications, digestive tract perforation or abdominal cavity infection
• The tumor invades the duodenum or the upper segment of the jejunum Individuals whom the investigator deems unsuitable for participation

Primary and secondary outcome measures could be shared without sharing patient privacy. Interested parties can contact by email