Practical Gastrointestinal Endoscopy

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CHAPTER 6
(a)
(b)
Fig. 6.44–Rotation of the vessel
pattern (from (a) to (b)) indicates
rotation of the colon, so the
endoscopist needs to change the
steering direction.
when talking to them—in order to concentrate on the monitor
view. It is perfectly possible to hold a conversation or to give
instructions without eye contact, and it can be very important
to do so. Some acute bends or small polyps, for instance, may
slip from view in the moment that the endoscopist looks away,
and then take a surprising time to find again. Intense concentration,
on both mechanical and visual aspects of the procedure,
makes colonoscopy quicker and more efficient. It takes all the
endoscopist’s faculties to assess the view, predict the correct
action, keep a running mental log of decisions taken and their
result, while constantly optimizing the situation or reversing
ineffective actions rapidly when necessary. Colonoscopy is an
algorithm of small responses to ever-varying situations. It takes
a surprising degree of alertness, motivation and concentration
to do it efficiently.
Push-through
Fig. 6.45–A very long sigmoid
may allow the scope to loop
enough to avoid a hairpin bend
(and lateral imager view may
show spiral configuration).
Gentle ‘push through’ the sigmoid colon, using careful steering
combined with ‘persuasive pressure’ may allow the scope
to slide successfully in a spiral around the sigmoid and up into
the descending colon. This typically occurs in long colons with
longer, more mobile, mesenteries which allow the instrument
to loop upwards but then adapt to allow spiral passage into
the descending colon, without the acute hairpin bend usually
formed by N-loop stretch (Fig. 6.45). Paradoxically, shorter sigmoid
loops tend to require more subtlety and cause more pain,
since their shorter mesenteric attachments are more aggressively
stretched.
Pain on passing the sigmoid colon indicates looping and potential
danger of damage to the bowel or mesentery. Having to use force
or cause pain is inelegant as well as potentially dangerous, and
should be avoided as far as possible. Before using force, and at
any stage during colonoscopy when pushing in may cause pain
due to looping, the patient is warned beforehand (e.g. ‘this will
hurt for a few seconds, but there is no danger’). Inward push
should also be applied gradually, avoiding any sudden shoves
and should be limited to a tolerable time—no more than 20–30
seconds. Looping pain stops at once when the instrument is
withdrawn slightly. There is no excuse for long continued periods
of pain, even in those miserable examinations when recurrent
looping cannot be avoided. However, as a last resort, it may
be preferable to persuade the instrument around a sigmoid spiral
into the descending colon quickly and successfully, rather than
to struggle on with repeated failed attempts at straightening it
within the sigmoid. Stretch pain is distressing for the patient and