Maneuvering the Endoscope

The novice often has difficulty passing the endoscope from the bulb into the descending duodenum. To understand the necessary maneuvers, note that the endoscope as a whole forms a U-shaped loop and that the flexible tip lies within the bulb in a more or less straightened position. The bulb is located cranial and slightly lateral to the pylorus and extends posteriorly to the junction of the bulbar and descending duodenum at the superior duodenal angle. From there the duodenum descends in the familiar C-shaped arch.

Retroflexing, Rotating, and Advancing the Scope

The endoscope is advanced through the bulb to the superior duodenal angle. From this vantage point, the first valvulae conniventes can be seen. To pass into the descending duodenum, the endoscope is advanced just until it abuts on the distal bulb wall. Now three things must occur simultaneously. The endoscope is:

1. Retroflexed at the tip by turning the control wheels,

2. Rotated clockwise, and

3. Slightly advanced.

This has the following effects: The retroflexion maneuver raises the endoscope tip out of the plane of the diagram (1 in Fig. 2.66). Rotating the shaft to the right (2) angles the deflected tip into the introitus of the descending duodenum, and simultaneously advancing the shaft (3) moves the endoscope farther down the descending limb.

This maneuver can be reproduced with the hand (Fig. 2.67). Hold your left arm in front of you in a supinated position and look at the palm. Now angle the palm toward you (retroflexion) and rotate the forearm to the right (clockwise rotation) while moving the arm forward (advancing). The hand now points into the descending duodenum.

Fig. 2.67 Passage through the duodenal bulb. The left hand demonstrates the spiraling motion around the superior duodenal angle

Fig. 2.67 Passage through the duodenal bulb. The left hand demonstrates the spiraling motion around the superior duodenal angle

Fig. 2.66 Passage into the descending duodenum. The necessary maneuvers are shown: 1 retroflexing the tip, 2 rotating to the right, 3

advancing p = pylorus db = duodenal bulb ded = descending duodenum a = antrum

- Fig. 2.68 Anterior and posterior walls of the duodenal bulb

- Fig. 2.68 Anterior and posterior walls of the duodenal bulb

View 7

View 7

The instrument tip is in the pylorus. The view is the same, regardless of whether the instrument is advanced or withdrawn: The duodenal bulb appears as a "bulbous" or cylindrical structure of variable length. With a standard instrument position, the junction of the bulb with the second part of the duodenum will be located below and to the right. Try to distinguish between the anterior and posterior walls of the bulb. This is aided by knowing the position of the patient and that the endoscope forms a U-shaped loop in the stomach, turning the image "upside down" (analogous to bending the head far backward and seeing the edge of the upper eyelid at the bottom of the visual field).

- Fig. 2.69 Entrance to the descending duodenum

- Fig. 2.69 Entrance to the descending duodenum

View 8

On reaching the entrance to the descending duodenum, you can see the first valvulae conniventes. The lumen of the duodenum continues downward and to the right from the endoscopist's perspective. The deflection/rotation/advance maneuver for entering the descending duodenum was

described above. When this maneuver is completed, the instrument tip should be within the descending duodenum. Evaluation was not possible during insertion of the scope. In the next step, the instrument is slowly withdrawn.

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  • marco
    How do you maneuver an endoscope?
    9 months ago

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