This clinical trial aims to evaluate the efficacy and safety of long needle and short needle in the treatment of internal hemorrhoids and rectal prolapse through CAES (Cap-assisted endoscopic sclerotherapy).

Traditional endoscopic sclerotherapy for internal hemorrhoids require retroflection of the endoscope. Retroflection of the endoscope has blind areas and affects the precise operation. And, short-needle injection can easily lead to artificial ulcer and secondary bleeding. CAES is a new, minimally invasive endoscopic technique for the treatment of internal hemorrhoids and rectal prolapse. CAES was performed based on the requirement of the cap, endoscope, disposable endoscopic long injection needle, enough insufflated air and sclerosing agent. It can accurately control the injection angle, direction and depth under direct vision, and avoid iatrogenic injury caused by ectopic injection to the greatest possible extent. To investigate the effect of long needle and short needle on the outcome of CAES, participants with internal hemorrhoids and rectal prolapse were randomly assigned to a long needle group and a short needle group using a prospective, randomized, controlled study at multiple centers in China. The efficacy, adverse events and satisfaction of the two groups were observed.

Inclusion Criteria:

1. Patients with internal hemorrhoids and rectal prolapse, combined with external hemorrhoids or without external hemorrhoids.
2. Patients with bowel preparation.

Exclusion Criteria:

1. History of anoscopic/endoscopic sclerotherapy.
2. Patients with acute thrombotic external hemorrhoids.
3. Patients with serious internal hemorrhoids of grade IV.
4. Patients with anal stenosis, anal fissure, fistula, fecal incontinence, ulcerative colitis, Crohn's disease.
5. Patients with acute diarrhea in the past 24 hours.
6. Hypertensive patients with uncontrolled blood pressure, patients with cerebrovascular accident and obvious bleeding tendency, pregnant women, mental disorders and decompensated cirrhosis.