LITMIR.BIZ

Figure 6.26 Transverse colon loop. Like the sigmoid, the transverse colon is also typically very mobile and can result in an assortment of loops. Reduction techniques vary but often require a combination of torque with slow shaft withdrawal. The direction of torque required will depend on the nature of the loop.

      (Copyrighted and used with permission of Mayo Foundation for Medical Education and Research.)

The other mobile section of the colon, the transverse colon, also frequently requires loop reduction. Looping here is mainly caused by redundancy of this section of the colon looping down, resulting in multiple changes in the force vector of the scope. The reduction technique is similar to loop reduction in the sigmoid. If possible, the flexible tip of the scope should be advanced around the hepatic flexure and hooked around this turn by holding the scope dials in place. With appropriate torque and withdrawal, the transverse colon will be straightened out. The scope tip may advance considerably down the right colon during this maneuver (Figure 6.26) (Video 6.8). The direction of torque here can vary, however, like the sigmoid; the correct direction of torque should result in a sensation of decreasing resistance and modest scope tip advancement.

      Angulated turns

Acute turns can be encountered predominately in the sigmoid colon and flexures but can occur in any colon segment. These pose a significant problem to early trainees because they often cause the fellow to develop significant loops of the scope shaft as well as overinflation of the colon as they struggle to round the turn. This overinflation can lead to increasing the acuity of the angulation. The difficulty by trainees is predominately due to incorrect technique of overusing the dials to accomplish these turns. Attempting to use the dials to steer around turns results in acute angulation of the scope shaft at the junction between the steerable tip and the less flexible scope shaft. With this acute bend in the scope, the force vector with advancement will be directed along the scope shaft at the outside wall of the turn rather than where the scope tip is pointing (Figure 6.27a). This resistance to scope advancement will be transmitted back along the scope shaft to the endoscopist's hand or to an area of mobile colon where a loop will develop. In acute turns such as these, the one‐handed technique of using torque as the primary means of opening up the fold of a turn often results in less acute angulation of the scope tip and avoidance of this problem. This is accomplished by advancing the scope tip just beyond the fold on the inside portion of the acute turn. Up or down defection is used just enough to begin hooking the turn. The scope is then gently pulled back just keeping the scope tip off of the wall of the outside turn while just enough deflection or torque is used to keep the scope hooked around the fold on the inside of the turn (Figure 6.27b) (Video 6.9) . This hooking and slight withdrawal maneuver pulls this first (inside turn) fold out of the way until the lumen beyond the turn can be visualized (Figure 6.27c). Now with scope shaft still relatively straight, the force vector from pushing will translate directly into scope tip advancement.