Endoscopy: From Diagnosis to Therapeutics

Abstract

Two decades ago, gastroenterologists used endoscopy for the diagnosis of Gastrointestinal (GI) lesions, thereby helping surgeons to localize lesion that necessitated resection and treatment with surgery. Today, the gastroenterology field has advanced beyond the diagnostic era and now, a large number of GI lesions can be treated via endoluminal procedures performed by the gastroenterologist with no need for surgical intervention.In recent years, the improvement of endoscopic imaging and tools, such as snares, clips and needles which can be delivered through the endoscope channel, have helped to change the field of gastroenterology. This allowed for the development and advancement of Endoscopic Mucosal Resection (EMR) and Endoscopic Submucosal Dissection (ESD). The pioneers of EMR and ESD were from Japan and the first articles describing these techniques were published in the 1990s. 1,2Two classification systems are used for describing GI lesions to be considered for EMR and ESD. One system is the Japanese classification 3 and the second is the Paris system, which was proposed in 2002. 4 The Japanese classification was originally developed for early gastric cancer management, but it can be applied to lesions throughout the GI tract. Once lesions are classified, EMR can be performed in different GI locations, including the esophagus, stomach, colon and rectum. When lesions are more complex and beyond the mucosa, ESD can be performed with careful dissection.Endoscopic ultrasound (EUS) may be useful in deciding whether to perform EMR or ESD. EUS can aid in determining the penetration of the tumor to layers beyond the mucosa when the lesion is localized in proximal parts of the colon. If the lesion cannot be reached by a regular EUS endoscope special high frequency mini-probes may be used through the colonoscope working channel.Two methods are used in performing EMR. The first method is 'suck and cut' and the second method is 'lift and cut'. Both usually begin with a submucosal injection prior to resection of the lesion the suc and cut method may be used also without submucosal injection especially when being performed in the esophagus. The injection is used to expand the submucosa, separating the deeper muscolaris propria from the more superficial mucosa and submucosa layers. Several solutions may be used as the injectate. These include normal saline with or without diluted epinephrine, hypertonic saline, dextrose solution, sodium hyaluronate, fibrinogen combination, glycerol, and fructose solutions all of those may be mixture with methylene blue depend on the preference of the endoscopist.5-8 Conio, et al. compared the solutions and showed that the disappearing time of normal saline is approximately 3 minutes with or without epinephrine, while the disappearing times of 50% dextrose and 10% glycerol and hyaluronic acid solutions were 4.7, 4.2 and 22 minutes respectively. 9After injection, one of the two resection methods can be applied. The 'suck and cut'