What is a double balloon small bowel microscope? What is the difference between it and the ordinary propulsion small intestine microscope? Why can it detect the deep part of the small intestine that cannot be detected by ordinary colonoscopy and diagnose and treat the diseases that cannot be diagnosed by ordinary colonoscopy? This starts from the special anatomical structure of the small intestine. The small intestine is the longest digestive tube in our body, and the total length of the small intestine in adults can reach 5~7 meters, it is located in the middle of our digestive tract, so it is far from the mouth and anus, and it is tortuous and free in the abdomen, which greatly increases the difficulty of entering the mirror and observation during endoscopy. The double balloon small intestine microscope is actually an outer tube with an airbag at the tip in addition to the original advancing small intestine microscope. The use of the outer tube increases the stiffness of the small bowel scope to a certain extent and facilitates access to the scope. Just like the elastic band we wear for pants, the elastic band is soft, so it is difficult to put in, but if you use a chopstick to help, you can easily send the elastic band in. When the two airbags are inflated, it can make the endoscope head and the outer casing fixed relative to the intestinal wall and not easy to slide. Slowly straightening the endoscope and the outer casing can shorten the intestinal canal, just like when we stretch our arms into a sleeve and roll up the intestinal canal like a cuff, in order to facilitate deeper probing of the lens into the small intestine. Through a series of operations of repeated inflation and deflation of the two balloons, advancing the cuff and pulling backward to shorten the intestinal canal, the lens can generally reach the middle and lower ileum, and part of it can reach the terminal ileum, a depth of examination that cannot be reached by ordinary small bowel scopes. This depth of examination cannot be reached by ordinary small intestine microscopy. By entering the microscope through the mouth and through the anus respectively, the whole small intestine can be examined comprehensively, thoroughly and without blindness. The double-balloon small intestine microscope is called the Sherlock Holmes of intestinal examination, which not only has a wide range of examination, a direct view of the entire small intestine, and a clear understanding, but also has the common advantages of ordinary electronic endoscopy: clear images, controlled operation, the ability to take biopsies under the endoscope, clarify the nature of the lesion, and carry out treatment. In cases like Mr. Liu’s, direct hemostasis through titanium clips and electrocoagulation under the microscope has obvious advantages over drug and surgical treatment. Regular review and polypectomy of patients with multiple polyps in the small intestine can also be performed under double balloon small intestine microscopy, which can prevent complications such as intestinal adhesions, intestinal bleeding and tumors after surgery and avoid multiple open surgeries. In addition, double-balloon small intestinal microscopy can also provide a clear diagnosis and treatment of intestinal stenosis caused by Crohn’s disease or intestinal stenosis due to other etiologies. Since the acquisition of the double-balloon small bowel microscope in 2007, the Gastrointestinal Endoscopy Center of CUH of Southeast University has performed examination and treatment for nearly 1,000 patients. Compared with other endoscopic examinations, the time of small intestine examination is relatively long, about 2~3 hours, but the examination is well tolerated by patients under conscious sedation or general anesthesia, and the safety is positive.