Practical Gastrointestinal Endoscopy

44
CHAPTER 4
Fig. 4.11 The route to the pylorus
anddown the duodenum
is a clockwise spiral around the
vertebral column.
The four walls of the stomach are examined sequentially by a
combination of tip deflection, instrument rotation and advance/
withdrawal. The field of view during the advance of a four-way
angling endoscope can be represented as a cylinder angulated
over the vertebral bodies; the distended stomach takes up an
exaggerated J-shape with the axis of the advancing instrument
corkscrewing clockwise up and over the spine, following the
greater curvature (Fig. 4.11). Thus, to advance through the stomach
and into the antrum
• angle the tip up increasingly;
• rotate the shaft clockwise.
This clockwise corkscrew rotation through approximately
90° during insertion brings the angulus and antrum into endon
view (Fig. 4.12); it may be necessary now to deflect the tip a
little downwards to bring it into the axis of the antrum (Fig. 4.13,
4.14), so that it runs smoothly along its greater curve. The motor
activity of the antrum, pyloric canal and pyloric ring should be
carefully observed. Asymmetry during a peristaltic wave is a
useful indicator of present or previous disease.
Through the pylorus into the duodenum
The pyloric ring is approached directly for passage into the duodenum.
During the maneuver it is convenient to use only the left
Fig. 4.12 The angulus and antrum
comeinto view …
… then angle down to
see the pylorus in the axis of the
antrum.