Practical Gastrointestinal Endoscopy

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CHAPTER 6
Fig. 6.41–A reversed alpha spiral
loop due to a persistent descending
mesocolon.
basis that ‘the view is good’—in spite of the protests of the patient.
Pain is the commonest warning of loop formation, but it is more
subtle to recognize a loop from loss of ‘one-to-one’ relationship between
the amount of shaft being inserted and inward progress
of the scope tip. ‘Paradoxical movement’ , the instrument apparently
sliding out as the shaft is pushed in (or vice versa), indicates
that there is a substantial loop.
There may be more than one loop, resulting in the instrument feeling
‘jammed up’. As the shaft loops more and more it becomes
progressively less responsive to manipulation. Because of the
increasing friction in the wires leading down to the bending
section, the angulation controls also feel stiffer and stiffer—but
have less and less effect. The difficulty is that inexperienced and
tense endoscopists don’t notice this and all too easily become
deaf to protest, overgenerous with sedation and liable to think
that forceful management of the colonoscope is ‘normal’. It is
important to be aware that colonoscopy can be a deft and gentle
procedure, to expect to hold and feel the instrument in the fingers
(Fig. 6.19), and to be aware that most loops can (and should) be as
rapidly removed as they have formed.
Avoiding or minimizing sigmoid loops
Sigmoid looping of some degree is unavoidable as the scope pushes
toward the apex of the sigmoid colon. It helps to warn the patient
when ‘stretch pain’ will be felt, and to try to keep this to 20–30
seconds. In this time the scope should slide around the whole
of a short sigmoid loop but, in longer colons, pull back to give
the patient relief and to try to reduce whatever loop has started
to form. It may be worth pointing out that the typical sigmoid
colon is entirely passive, tortuous perhaps and subject to gravity.
It is the force of colonoscope insertion that creates loops, and the
challenge to the colonoscopist is to minimize or modify looping
in any way that makes insertion easier.
Abdominal hand-pressure often helps a little during sigmoid insertion,
since the sigmoid loop frequently loops anteriorly close
to the abdominal wall (see Fig. 6.34)—especially in those with a
protuberant abdomen. The assistant compresses non-specifically
over the lower abdomen, which opposes the sigmoid loop, may reduce
stretch pain and can make the scope slide around more easily
because the loop is made smaller. Assistant hand pressure is
only relevant during the (?20–30·seconds or so) needed for inward
scope-push. There is no need to fatigue the assistant by asking for
more prolonged hand pressure, especially as in around 50% of
patients the sigmoid loop is not near the abdominal surface.
Push little and slowly; pull often and fast. The challenge in a longer
and tortuous sigmoid is to progress the instrument tip through
without repeatedly losing the view, minimizing colon and colonoscope
looping as far as possible. Pushing movements should