Clinically, chronic intractable constipation includes habitual constipation, exit-obstruction constipation and slow-transit constipation of the colon. Slow-transit colon constipation is a type of intractable constipation characterized by diminished colonic motility, which is characterized by abnormally slowed fecal transport in the colon, no bowel movement, and significantly reduced stool frequency, and used to be treated purely by conservative internal medicine, which is more difficult and ineffective in severe cases. Etiology: The pathogenesis is complex, with psychiatric factors, enteric neuron lesions, Cajal interstitial cell abnormalities, smooth muscle degeneration, central neuropathy, and gastrointestinal peptide hormone abnormalities all providing partial explanations, but it is difficult to outline a clear etiology. Clinical manifestations: progressive decrease in the number of unexplained spontaneous bowel movements, absence of bowel movements, difficulty in defecation, one bowel movement every 4-15 days, accompanied by a feeling of incomplete bowel movements and abdominal distension. Most patients have a history of using stimulant laxatives (especially anthraquinone laxatives) for bowel movements. In patients with a history of long-term laxative use, colonoscopy showed intestinal mucosal hyperpigmentation and widespread melanosis of the colonic mucosa, and drug resistance was easily developed after long-term laxative use. Pathological changes: Pathology confirmed that the decrease of colonic interstitial ganglion cells with vacuolar degeneration, decrease of interstitial ganglion cells, degenerative changes of the nerve plexus, due to the decrease of intestinal interstitial ganglion cells, degeneration and other changes, resulting in malnutrition of the intestinal wall, thus further decreasing the peristalsis of the colon, dilatation and thinning of the intestinal wall, further aggravating the symptoms of constipation. Surgical case selection criteria: STC is a dysfunctional disease of the colon rather than an organic lesion, so surgical treatment should be very careful, and surgical indications should be strictly controlled. 1.Ineffective after 6 months of strict medical treatment; 2.Significantly prolonged colonic transport test and more than 2 colonic transport tests at different times; 3.No obvious organic cause by fecal imaging, colonoscopy, balloon expulsion, etc., no clinical evidence of diffuse intestinal motility disorder, such as irritable syndrome; 4.No obvious clinical anxiety, depression and psychiatric abnormalities, and only those who have a strong demand for surgery Consider surgical treatment. Surgical options: 1) total colectomy and ileorectal anastomosis; 2) subtotal colectomy and cecum-rectal anastomosis; 3) colectomy. The literature reports that the efficiency of total colectomy and ileorectal anastomosis is as high as 95%, while the treatment effect of colectomy is poor and the recurrence rate is as high as 50% or more. Most domestic scholars advocate ileocecal subtotal colectomy and ileorectal anastomosis, which not only preserves the physiological function of ileocecal valve but also improves the symptoms of constipation. Professor Tian Hongyu of Zhejiang University believes that both subtotal resection of the colon and lower ileosigmoid anastomosis or cecum-rectal anastomosis can improve the symptoms of constipation, and there is no significant difference in efficacy. However, because the cecum is more fixed during cecum-rectal anastomosis, the cecum needs to be turned and anastomosed with the rectum, whereas when the ileum is free and anastomosed with the lower sigmoid colon, the intestine does not need to be turned and the anastomosis is tension-free after the anastomosis, so the operation is relatively more concise, and most patients do not have a lot of stools after resection of the ileum. Therefore, ileosigmoid anastomosis is preferred. Postoperatively: for those with diarrhea symptoms, compound phenelzine can be given orally for an average of 67 days (61 days with ileocecal preservation and 69 days without ileocecal preservation). The duration of administration of live bacteria drugs to promote intestinal motility is 21 to 35 days after surgery. Complications: mainly abdominal distension and pain and intestinal obstruction, the incidence of intestinal obstruction can reach (8%~69%), reoperation rate 10~100%. Efficacy: The cases are strictly screened, and the total efficiency can reach more than 90%.