The remaining 40 centimeters after small bowel resection may be caused by necrosis of the small bowel or due to factors such as injury to the small bowel. If intestinal obstruction, mesenteric artery embolism, or intestinal torsion occurs in the small bowel, it may lead to ischemia and necrosis of the small bowel, which requires surgical treatment and complete removal of the necrotic small bowel. If the necrosis of the small bowel is relatively extensive, the small bowel may be left at only 40 centimeters after surgery. If trauma has occurred in the abdomen and the trauma is relatively severe, it may lead to extensive damage to the small bowel and surgery is needed to remove the damaged small bowel. The removed small bowel may be relatively long, and only 40 centimeters of the small bowel may remain after the surgery. The remaining 40 centimeters of the small intestine after removal must follow the doctor’s instructions for treatment, medication and daily diet, otherwise other complications may occur, which will seriously affect the quality of life.