Blind Loop Syndrome

　　The blind loop syndrome is mainly caused by intestinal stenosis. The stenosis of the intestinal lumen is caused by tumors and inflammation in the colon, and the diseased tissue cannot be removed due to systemic or local reasons. To solve the problem of colonic obstruction, only a short-circuit anastomosis between the ileum and the colon can be performed to resolve different degrees of intestinal obstruction. During the anastomosis, when performing a transverse colon loop anastomosis or a bilateral anastomosis between the ileum and sigmoid colon, the ileum is not twisted or crossed, and it is directly anastomosed with the colon, resulting in a retrograde peristalsis anastomosis. That is, a part of the proximal ileum contents enter the旷置的colon first, and then enter the distal colon. If it is not a complete obstruction, a part of it passes through the stenosis into the proximal colon, causing a series of pathological changes.

　　In patients with blind loop syndrome, because part of the content in the proximal ileum enters the unused distal colon, causing this part of the colon to have peristalsis, sending most of the content into the distal colon; and another part passes through the narrow area into the adjacent proximal colon. This part of the content has two pathways for excretion: one is to pass through the narrow area in the direction of peristalsis and re-enter the distal colon; the other is to enter the distal colon from the unused distal ileum through retrograde peristalsis.

　　The above process of ileal content movement repeatedly stimulates the unused intestinal tube and accumulates content, leading to the expansion of the unused colon, especially at the narrow proximal end. Over time, the colon wall thickens, forming a mass. When the peristalsis passes through the narrow area, or produces pain during peristalsis, it can cause a series of symptoms such as nausea and vomiting. The purpose of the bypass anastomosis is to allow the lesion site to rest, or to reduce the stimulation of tumors and slow down their growth, or to promote the early elimination of inflammation in lesions such as inflammation. If the anastomosis is in the opposite direction of peristalsis, the growth of tumors accelerates, and the healing of inflammation slows down.

　　Blind loop syndrome is prone to complications such as colon tumors and inflammation. In addition, excessive proliferation of bacteria in the small intestine can damage the small intestinal mucosa, affecting the absorption of nutrients in the intestines. At the same time, a large amount of vitamin B12 is consumed by bacteria, causing vitamin B12 deficiency. A large number of bacteria can decompose conjugated bile salts into unconjugated bile salts, affecting the formation of fat micelles, thus affecting the absorption of fat substances. Unconjugated bile salts can also stimulate peristalsis, so almost all cases of blind loop syndrome are accompanied by steatorrhea and diarrhea.

　　The clinical symptoms of blind loop syndrome mainly include abdominal pain and distension, accompanied by nausea, vomiting, and bowel sounds, as follows:
　　1. Abdominal pain
　　Accompanied by nausea and vomiting, symptoms can occur after the recovery of intestinal peristalsis after surgery, pain can be abdominal distension, dull pain, and severe cases can have colicky pain.
　　2. Abdominal distension
　　Abdominal distension and discomfort at the site of the primary intestinal obstruction, as well as bowel sounds may also occur.
　　3. Signs
　　The main signs are the signs of primary intestinal obstruction at the lesion site, such as tumors and tenderness, followed by intestinal dilation and peristaltic waves at the proximal site of intestinal obstruction, and palpable sausages and dilated intestinal tubes.

　　The prevention of blind loop syndrome lies in colonic obstruction surgery. During colo-rectal anastomosis, it is essential to follow the direction of peristalsis, consistent with the direction of large intestine peristalsis, and to reinforce the suture near the anastomosis with 2 to 3 stitches, and to suture the seromuscular layer to make the peristalsis direction more consistent. If the distal ileum and the proximal colon are anastomosed at both ends of the ileocecal anastomosis, and the proximal ileum and the distal colon are anastomosed, the two anastomotic orifices should be about 5 cm apart to prevent reflux. If the lesion does not cause complete obstruction of the intestinal lumen, it is a major error to seal the distal ileum and perform an end-to-side anastomosis at the proximal ileum near the colon lesion. Because as the lesion develops into complete obstruction, the secretion of intestinal mucosa between the sealing orifice and the lesion increases, gradually expands, and can rupture to form peritonitis, which is a surgical error, and should be vigilant.

　　The examination items for blind loop syndrome mainly include X-ray and B-ultrasound, as follows:
　　1. X-ray Examination
　　Abdominal X-ray film shows dilated bowel (near the obstruction site), small bowel contrast study shows that barium enters the distal bowel in retrograde from the anastomosis, and a portion of it passes through the narrow site in retrograde into the proximal bowel, which is then pushed into the distal anastomosis by antegrade peristalsis, or retrograde to the anastomosis site.
　　2. Type B Ultrasound
　　The original site of the colonic lesion and the proximal dilated bowel can be palpated.

　　Patients with blind loop syndrome should pay attention to dietary balance. Eat more vegetables and fruits, supplement vitamins, and mainly choose light and high-fiber foods, such as spinach, celery, winter melon, luffa, pumpkin, mung beans, soybeans, rapeseed, cauliflower, mushrooms, kelp, radishes, and lotus root.

　　The Western medicine treatment for blind loop syndrome mainly includes drug treatment and surgical treatment, as follows:
　　1. Drug Treatment
　　1. Refrain from eating for 3 to 5 days and observe for changes in the condition.
　　2. Administer intravenous fluids to correct electrolyte and water balance disorders.
　　3. Administer antibiotics to prevent infection.
　　2. Surgical Treatment
　　Change the reverse peristalsis of the colonic anastomosis back to antegrade peristalsis after conservative treatment is ineffective. The intestinal loop anastomosis can be removed and the direction reversed for suture. If bilateral anastomosis, the proximal ileum and colonic anastomosis should be removed, the colonic anastomosis closed, and an ileocolonic anastomosis performed 5 cm or so away from the distal ileum and colonic anastomosis.