This study compares two ways of treating acute uncomplicated appendicitis, which is a mild form of appendicitis. In the Direct Visualization ERAT group, participants will receive Endoscopic Retrograde Appendicitis Therapy (ERAT). This is a minimally invasive, non-surgical treatment that uses a flexible endoscope passed through the colon to reach the appendix, clear the blockage, and drain the infection. In the Surgery group, participants will undergo Laparoscopic Appendectomy (LA), which is the current standard surgical treatment to remove the appendix. The purpose of this study is to determine whether ERAT is as safe and effective as standard surgery for treating uncomplicated appendicitis.

Before treatment, each participant will have a CT scan of the lower abdomen with contrast to confirm uncomplicated appendicitis and to rule out any signs of more serious infection. Participants will then be randomly assigned to either the ERAT group or the surgery group, and they will be informed of which treatment they will receive. Regardless of the group, all participants will receive the same supportive care, including pain relief, close monitoring, and a single dose of antibiotics before treatment. After the procedure, participants will stay in the hospital for at least 24 hours for observation. Follow-up will include an outpatient visit at 2 weeks, and telephone follow-ups at 1 month, 3 months, 6 months, and 1 year to monitor recovery and ensure that appendicitis does not recur.

This is a multicenter, open-label, randomized, non-inferiority trial comparing Direct Visualization Endoscopic Retrograde Appendicitis Therapy (ERAT) with Laparoscopic Appendectomy (LA) for the treatment of adult acute uncomplicated appendicitis (AUA). A total of 376 participants will be enrolled across 14 hospitals in China, and randomized in a 1:1 ratio to either ERAT or LA after providing informed consent.

Adults aged 18 years or older with CT-confirmed first-episode AUA are eligible. Key exclusions include complicated appendicitis, bowel obstruction, intolerance to colonoscopy or bowel preparation, poor operative candidacy, pregnancy, severe organ dysfunction, or concurrent participation in another clinical trial.

Interventions will be performed within 24 hours of admission. ERAT involves the use of a direct visualization appendicoscope to access the appendiceal lumen, irrigate pus and debris, and remove or fragment appendicoliths under direct vision. A short plastic stent may be placed if drainage is required. LA will be performed according to standard laparoscopic surgical techniques. Follow-up assessments will include an outpatient visit at 2 weeks and telephone follow-ups at 1, 3, 6, and 12 months.

The primary outcome is 30-day treatment success, defined as successful completion of the assigned procedure, resolution of symptoms, discharge without further surgery, and absence of recurrence. This study aims to provide robust evidence supporting the safety and effectiveness of ERAT and to inform future clinical guidelines for the management of acute uncomplicated appendicitis.

Inclusion Criteria:

1. Age ≥ 18 years.
2. Diagnosis of first-episode acute uncomplicated appendicitis (AUA) confirmed by CT scan of the lower abdomen. AUA is defined as acute appendicitis without evidence of abscess, perforation, gangrene, or tumor.
3. Provision of written informed consent.

Exclusion Criteria:

1. Complicated appendicitis, defined as acute appendicitis with perforation, gangrene, periappendiceal abscess or phlegmon, generalized peritonitis, or radiologic evidence of extraluminal appendicolith, extraluminal air, periappendiceal fat stranding, or appendiceal mass.
2. Severe intestinal adhesions or bowel obstruction.
3. Intolerance or contraindication to bowel preparation or colonoscopy (e.g., intestinal perforation or bowel obstruction).
4. Poor general condition precluding tolerance of abdominal surgery.
5. Abdominal pain caused by other diseases as confirmed by CT or other diagnostic examinations, including inflammatory bowel disease, urinary tract disease, or gynecological disease.
6. Pregnancy.
7. Severe dysfunction of major organ systems, including but not limited to cardiac, pulmonary, renal, hepatic, or hematologic systems.
8. Current enrollment in another clinical trial.
9. Any condition that may prevent the participant from completing all study requirements.

Undecided