Practical Gastrointestinal Endoscopy

COLONOSCOPY AND FLEXIBLE SIGMOIDOSCOPY 141
sciously de-angulate a little so that the instrument runs around
the outside of the bend (see Fig. 6.23), even if this means worsening
the view somewhat.
3–Deflate the colon slightly to shorten the flexure and make it
malleable.
4–Apply assistant hand pressure over the sigmoid colon. Any
resistance encountered at the splenic flexure is likely to result
in stretching upwards of the sigmoid colon into an ‘N’-loop or
spiral loop, which dissipates more and more of the inward force
applied to the shaft as the loop increases (Fig. 6.62). It is immediately
obvious to the single-handed endoscopist that such a loop
is forming, because the ‘one-to-one’ relationship between insertion
and tip progress is lost—in other words, the shaft is being
pushed in but the tip moves little or not at all. Pull back again to
restraighten the shaft if this occurs.
5–Use clockwise torque on the shaft. As explained above, the clockwise
spiral course of the sigmoid colon from the pelvis to its
point of fixation in the descending colon means that applying
clockwise torque to the colonoscope shaft tends to counteract
any looping tendency in the sigmoid colon while pushing in (Fig.
6.63). Clockwise torque will only be effective to keep the shaft
straight if any significant looping has been removed and if the
descending colon is normally fixed. Because the tip is angulated,
applying clockwise shaft torque may affect the luminal view into
the transverse colon, and readjustment of the angulation controls
may be needed to redirect the tip.
6–Finally, push in, but slowly. The instrument tip cannot advance
around the splenic flexure without some degree of inward push.
So, as well as clockwise twist, continued gentle inward pressure
is needed (aggressive pushing simply re-forms the sigmoid
loop). All that is needed for success is firm inward pressure
on the shaft—which causes gradual millimeter-by-millimeter
inward slippage of the tip into the transverse colon. While pushing
in it may be possible to deflate again, or it may be necessary to
make compensatory movements of the steering controls. A combination
of these various maneuvers, together or in sequence,
using the angulation controls to ‘squirm’ the bending section, or
the suction valve to aspirate a little more, may help the tip and the
stiffer shaft behind it to slide around the splenic flexure.
7–If it does not work, pull back and start again. If the tip is not progressing
but, from the amount of shaft being inserted, it is obvious
that a sigmoid loop is re-forming, pull back and run through
all the above actions again before pushing in once more. It may
take two or three attempts to achieve success.
8–If a variable scope is being used, stiffening it—once the splenic
flexure is reached and the instrument is straightened—may stop
shaft re-looping in the sigmoid, and let inward push slide the tip
straight around into the transverse with remarkable ease.
Fig. 6.62–Control sigmoid looping
by hand pressure to help pass
the splenic flexure.
Fig. 6.63–Twist the shaft clockwise
while advancing to keep the
sigmoid straight.