Selective supra-mucosal resection (TST surgery) is a new technique recently developed on the basis of PPH surgery, which not only corrects the pathophysiological changes of hemorrhoids, but also preserves the normal anal cushion and mucosal bridges without removing all of them, thus maintaining the fine function of the anus, which can reduce surgical trauma, shorten treatment time and make hemorrhoid surgery more minimally invasive. Technical principle: selective supra-anal mucosal resection (TST surgery) uses a special anoscope to form different open-loop windows, exposing only the mucosa of the hemorrhoid area, which is more targeted; preserves the mucosal bridges between hemorrhoids and the normal mucosa of the asymptomatic hemorrhoid area, avoiding the production of circular scarring and effectively preventing anal stenosis; at the same time, it reduces the disturbance and stimulation of the migrating epithelial domain of the rectum and anal canal, alleviating postoperative swelling Discomfort. Scope of use: It has a very ideal treatment effect on internal hemorrhoids, external hemorrhoids, mixed hemorrhoids, circumferential hemorrhoids, severe hemorrhoid prolapse, prolapse, etc. It is especially used for the treatment of Ⅲ and Ⅳ degree internal hemorrhoids. Technical advantages:TST technology is characterized by simple operation, mild postoperative pain (almost painless), few complications, short recovery time, good efficacy, does not affect work and study, and high patient satisfaction. Contraindications: TST is not recommended for pregnant women, children, those with intractable constipation, pelvic tumors, portal hypertension, Buicka syndrome, or those who cannot tolerate the procedure. TST surgical instruments:The anoscopes of TST instruments are divided into: single-opening anoscope, double-opening anoscope and triple-opening anoscope.