Figure 6.12 Rectal intubation techniques. This illustration demonstrates the three common methods of inserting the scope through the anal canal: (a) tangential approach, (b) along‐side finger, and (c) straight insertion.
(Copyrighted and used with permission of Mayo Foundation for Medical Education and Research.)
1 Tangential approach: The scope is held in the right hand at about 10 cm with the index finger down near the tip. The scope tip is then positioned at the anal canal at roughly a 45° angle. The index finger then gently pushes the tip of the scope though the anal canal and the scope is then advanced. This technique gives better control of the tip during insertion. With this technique and the next, the second (outer) glove on the right hand remains on until after scope insertion and can then be removed and discarded.
2 Along‐side finger: The right index finger is inserted into the anal canal and the scope is inserted alongside this as the finger is withdrawn.
3 Straight insertion: The scope is held with the right hand at about 20 cm from the tip and is positioned perpendicular to the anal canal. The scope tip is then inserted straight into the rectum. This is probably the most direct approach and most commonly used method.
Scope advancement
Once in the rectum, the objective is to advance the scope quickly and safely to the cecum. In order to accomplish this, the endoscopist needs to be able to steer the scope tip in the direction desired. This is done with a combination of the scope dials as well as torque of the scope. Being able to locate the colonic lumen when lost is also a mandatory early skill. Barring looping of the scope or tight angulations, the cecum can sometimes be reached with these simple techniques alone. Other skills such as loop reduction, navigation of angulated turns, and terminal ileum (TI) intubation will be covered later in this chapter.
Tip control
The large (up/down) dial is controlled with the thumb. The scope's camera is fixed in relation to the scope's axis, hence the up or down deflection described earlier is always in relation to the image on the video monitor. “Up deflection” of the camera (or “thumb down” on the dial) will always deflect the scope toward the top of the image displayed on the video screen and “down deflection” (or “thumb up”) will always aim the camera toward the bottom of the screen. For the teacher and student alike, it helps for the training center to conform to a single use of terms describing the desired action such as always using the terms “steer up” and “steer down” vs. “thumb down” and “thumb up.” Most find that describing which direction you want the camera to steer in relation to the video image as the most intuitive method as opposed to advising which way to turn the wheel with their thumb.
Torque
As trainees will quickly find, reaching the thumb to the smaller right/left dial can be difficult and awkward. Many trainees early in their training will be tempted to remove their right hand from the scope shaft and use this hand to turn the small dial. By correctly placing the scope's umbilical cable on the outside of the left arm (rather than running between the left arm and flank of the endoscopists), the scope handle rotates slightly bringing the control knobs slightly closer to the users thumb. However, with correct technique, the need for this small dial can be minimized. The most efficient method of steering is combining torque with use of the up/down dial. In general, experienced endoscopists would agree that, rather than using excessive right/left dial control, it is better to teach the use of scope torque in either direction to reorient the right or left turns in the lumen so that they are oriented toward the top or bottom of the screen. This is accomplished with the right hand rotating the shaft of the scope. Firm torque of the scope's shaft in the desired direction can rotate the entire shaft of the scope inside the patient and realign a horizontal turn in the lumen to one that is vertically oriented (Figure 6.13). Once in this position, the large up/down dial can be used to steer in the direction desired.
Scope advancement techniques
There are three techniques used to handle the scope. The “one‐handed” technique is the one most commonly used by experienced colonoscopists as it provides the most uninterrupted control of the scope shaft and is best suited to the predominant use of torque to maneuver the instrument (Figure 6.14). In this method, the dials are controlled with the left hand alone, relying primarily on the up/down dial. The right hand remains on the shaft of the scope providing torque, advancement, and withdrawal of the scope. A useful way to conceptualize this technique is to imagine flying a plane through a tunnel. If the pilot wishes to turn right, one cannot simply fishtail the plane to the right, instead the plane must roll right and then pull back on the stick (up). Occasionally, the right hand may still need to be brought up to control the smaller right/left dial but only with particularly tight turns, such as the splenic or hepatic flexure, where torque and up/down deflection may not be sufficient.
Figure 6.13 Torque to change from horizontal to vertical. The two images depict the same turn but in different orientations. In the first image (a), the turn goes off to the right and would require the use of the small left/right dial to navigate. However, after torque of the scope shaft 90° clockwise, this turn is now oriented vertically (b) and can now be navigated with the large dial alone.
Figure 6.14 One‐handed technique. With the one‐handed advancement technique, all of the dial control is done by the left hand, primarily using the large dial. The right hand is responsible for providing torque and advancement, and generally does not leave the scope shaft.
The “two‐handed” technique is favored by some experts who feel that when the thumb is used to cross over to the small dial, fine control of the large dial is not possible. Additionally, the left thumb cannot maximally deflect the small dial in either direction. Once the right hand has turned the small dial, it can be temporarily locked in this position
