Practical Gastrointestinal Endoscopy

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CHAPTER 6
around bends. This is particularly useful if the angle to be traversed
is acute or fixed, because simply trying to push around
will encounter severe resistance (often resulting in looping
rather than progress).
•–Torque steering involves first angulating up or down as appropriate
and, rather than using the lateral angulation control,
torquing (twisting, rotating) the instrument shaft clockwise or
counterclockwise with the right hand. Because the tip is already
slightly angled this rotation should corkscrew it around laterally
(Fig. 6.21), precisely and quickly, and will often make use
of the lateral angulation control unnecessary. Torquing is also
a valuable way of orienting the scope tip and bending section
in order to target lesions accurately, making biopsy-taking or
polypectomy quicker and easier. Torque steering is, inevitably,
affected by the direction in which the tip is angulated, With ‘upangulation’,
clockwise torque moves the tip to the right, whereas
it moves to the left if angulation is down.
•–When torque (maintained twist) is used to control a loop, steering
may have to be with the angulation controls. The principles
of loop control are discussed below, but strong twisting movements
are a key. It is essential to realize that if, in order to steer,
the torque applied to hold a loop straight has to be released, the
loop will re-form. Maintaining the shaft torque but applying the
relevant angulating control avoids this.
•–Steering with the lateral angulation control has least effect when
the tip is already maximally angled (up or down). Try this outside
the patient. When one control is fully angulated, applying
the other one swivels the bending section a little but hardly
affects the degree of angulation (Fig. 6.22). Vicious steering
movements are therefore rarely helpful (and can damage the
angulation control wires).
•–A fully angulated tip will not slide along the colon. It is easy to forget,
in the quest to get a view around bends, that overangulation
Up
Left
Right
Down
Fig. 6.21–With a clockwise shaft twist: (a) an up-angled tip moves to the right … (b)… and a down-angled tip
moves to the left.