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various advantages afforded by deconstructing skill sets in such a manner when designing or adapting their own training programs. Subsequent chapters will cover training in the major endoscopic procedures and in specific techniques using a variety of different perspectives. The reader is encouraged to approach these chapters with their own framework in mind.

      In this section, we will discuss the following skills, which we consider to be constant requisites in the technical performance of any form of gastrointestinal endoscopy. It is assumed that prior to introducing a trainee to the technical components of performing endoscopy, they have already become familiar with the various components of the endoscope, including the function of the air/water and suction buttons, as well as proper holding and handling of the endoscope and other practical aspects such as troubleshooting malfunctioning equipment. Ideally, these basic skills have been introduced to the trainee and practiced in an environment away from the patient until a minimum level of proficiency has been reached.

      1 Introduction of the endoscope: Comfortable and safe introduction of the scope into the GI tract through an orifice (oropharynx, anus, stoma).

      2 Navigation: Navigation of a flexible instrument through a tubular conduit until a goal or end point is reached.

      3 Overcome obstacles: Strategies to navigate across sphincters, around sharp curves, and through areas of resistance.

      4 Inspection: Careful and thorough inspection of the mucosal surface.

      5 Instrumentation: Advancing an instrument through an accessory channel to a specific point, while maintaining a stable view of the target and then subsequently performing the desired task.

      These skills will be discussed in some detail, including the nuances that affect their learning.

Introduction of the scope

      To begin any gastrointestinal procedure, the endoscope must first be inserted into the lumen of the GI tract. Introduction of the endoscope requires a clear understanding of the relevant regional anatomy.

      For upper GI endoscopy, this involves direction of the endoscope down the oropharynx into the esophagus. To avoid gagging, retching, and possible laryngospasm, the oropharynx should be appropriately anesthetized with a local anesthetic agent and the endoscope directed away from the vocal cords and into the esophagus. In some cases, intravenous sedation is useful to supplement the topical anesthesia. Appropriate patient positioning and education to avoid efforts at swallowing further add to the smoothness of this phase of the endoscopy. Patients with large anterior osteophytes of the cervical spine may pose particular risks for perforation, as might Zenker’s diverticula. Attention to these possibilities is mandatory for safe upper endoscopy.

For lower GI endoscopy, the endoscope needs to be introduced into the lumen, most often through the anus, but under some circumstances, through a stoma. Preceding the introduction of the endoscope with a properly performed digital examination is an essential adjunct to safe and comfortable intubation. This provides the opportunity to lubricate the entry, slowly relax the sphincter, and to evaluate the individual anatomy for direction and for any unexpected pathology or sites of potential obstruction.

      Endoscopy through a stoma requires some understanding of stomal varieties. A loop stoma is oriented at right angles to the long axis of the bowel. Imprudent introduction of the scope through the stoma can easily cause perforation through the antimesenteric side of the bowel. This is particularly prone to occur in patients whose bowel has been excluded, resulting in atrophy. End stomas are oriented in line with the long axis of the bowel. Digital examination may disclose angulation or kinks in the intra‐abdominal segment of intestine that must be negotiated when introducing the scope.

      Methods to assess the phase of introduction of the endoscope include rating of patient comfort, time to intubate, the number of attempts to intubate, and any complications related to the endoscope intubation, anesthesia, and sedation.

Navigation

      Once the endoscope is successfully introduced, the next goal is advancement of the scope to a specific extent, as indicated by the clinical reason for the endoscopy. For upper GI endoscopy, this is usually down to the third stage of the duodenum; for colonoscopy, it would be to the cecum, terminal ileum, or to an anastomosis, for example. Scope navigation is accomplished by a series of maneuvers that include tip deflection, scope rotation/application of torque, external compression of the abdomen, adjusting the patient position, insufflation and suction of air or fluids, and insertion and withdrawal of the scope.

      Control of the tip of the endoscope is necessary when navigating to maintain an adequate luminal view, as well as to assist in advancement of the endoscope. Depending on the type of endoscopy being performed, tip control may be done in different ways by nature of the physical characteristics of the endoscopes. Standard esophagogastroduodenoscopy (EGD) (hereafter referred to as EGD, or gastroscopy) requires very different maneuvers than endoscopic retrograde cholangiopancreatography (ERCP) or colonoscopy, for example. In the case of ERCP, the increased endoscope stiffness and oblique viewing angle mandates very different technical skills. Intubation, manipulation of the endoscope tip through the stomach, traversing the pylorus, and positioning in front of the papilla require very different maneuvers and changes in body position than are required for other procedures. It is our preference to train endoscopists to use the left hand to grip the handle of the endoscope and to manipulate the wheels using the thumb of the left hand for all procedures, particularly during colonoscopy. The main advantage of this approach is to reserve the right hand for advancement and withdrawal of the endoscope, and application of torque when necessary. This allows us to focus our trainees’ attention upon the sensation of resistance or torque in their right hand. If additional tip deflection is required, small movements of the wheels using the left thumb is typically sufficient. This awareness of changing resistance, possible impending scope movement/stability or response to torque is particularly important when attempting to perform maneuvers such as shortening the endoscope in ERCP, resolving a loop in colonoscopy, or when performing controlled small repositioning maneuvers in endoscopic ultrasound, for example. It is useful to also train in the use of imaging techniques such as fluoroscopy or scope imaging devices [10] for those situations when the endoscopic image does not provide sufficient information to guide scope navigation. Although some endoscopists prefer to use alternative navigation methods such as controlling tip deflection via two hands on both endoscopy wheels while an assistant advances, rotates, and applies torque to the scope, we feel that this is less than optimal for training purposes for a variety of reasons, particularly for more advanced or difficult endoscopic procedures and maneuvers and techniques.

      With appropriate insufflation (of air, water, or carbon dioxide), the lumen of the GI tract can be identified and the scope advanced to the desired limit of examination. Too much insufflation adds to patient discomfort, may precipitate cardiovascular instability, and can increase the risk of perforation or aspiration. Insufflation is required only to achieve sufficient distension of the bowel for an adequate view of the circumference of the bowel wall, to assist in identifying the lumen or differentiating the lumen from a diverticular opening, and to provide adequate focal distance between the lens of the scope and the object being viewed. The endoscopist should also be trained in the use of pharmacological agents that can assist in maintaining stability of position (e.g., in ERCP) or inspection (e.g., screening for early gastric cancer) by decreasing bowel contractions.

      The endoscopist should be familiar with the unique endoscopic characteristics of the portion of the GI tract being examined. For example, the sigmoid, descending colon, colonic flexures, transverse colon, and ileocecal region all have specific endoscopic appearances. In most cases, knowledge of these appearances is useful feedback for the endoscopist in knowing where he is within the colon and what strategies need to be used if advancement of the scope is not successful. This is particularly relevant during colonoscopy in which different strategies may be employed in the right versus the left colon. Furthermore, it is important to understand the concept of paradoxical movement. In this situation, the endoscope is being advanced, but its distal tip is retracting as a loop is forming within the bowel. Similarly, the endoscopist should recognize both in the endoscopic image

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