Bowel endoscopy technique

In the examination of the duodenum, the most widely used are duodenoscopes with lateral optics, which are most convenient for examining such an anatomically complex organ as the duodenum and performing operations on it. Duodenoscopy can also be performed using devices with end-on optics. They have the greatest advantages when examining patients who have undergone gastric resection using the Bilroth-II method.

Duodenoscopy with endoscopes with end optics begins with an examination of the pylorus, which is performed by bending the distal end of the endoscope upward and pushing the device forward. The lower the tone of the stomach and the more it sags, the more the end of the endoscope must be bent. If the endoscope is located at the pylorus, then it is possible to see a large part of the anterior and upper walls of the bulb, and with a slight bend of the intestine to the rear, even the area of the postbulbar sphincter of Kapandzhi can be examined.

By passing through the pyloric ring and changing the position of the distal end of the endoscope, it is possible to examine a large part of the walls of the duodenal bulb and its posterior curvature. With insufficient relaxation, the pylorus is spasmodically contracted, and effort is required to pass the endoscope, which falls deep into the cavity of the bulb and reaches the anterior-superior wall of the duodenum in the area of its upper curvature. In this case, either the field of vision turns red (the endoscope is closely adjacent to the mucous membrane), or the villous pattern of the mucous membrane is clearly visible (the endoscope is in close proximity to it). Sometimes the endoscope reaches the terminal part of the upper horizontal branch of the duodenum and even the descending part. Rapid passage of the pylorus and deep penetration of the endoscope into the intestine can lead to intestinal trauma and even its perforation in the presence of an ulcer.

The bulb of the duodenum after passing the endoscope behind the pylorus has the appearance of a triangular prism, the apex of which corresponds to the superior duodenal flexure. The anterior wall is located at 9 o'clock, the posterior wall at 3 o'clock. When examining the intestinal walls, it is necessary to evaluate their shape, tone, elasticity and extensibility during air insufflation.

When further inserting the endoscope, it is necessary to rotate it around its own axis clockwise and bend the distal end backwards (towards the back). The smooth surface of the bulb is replaced by a folded relief in the distal half of the upper horizontal branch of the duodenum, especially pronounced in the sphincter area. As the endoscope advances, the outer wall of the descending part of the duodenum appears in the field of view, against which it rests when moving forward.

To insert an endoscope with end optics into the descending part and examine the minor and major papillae of the duodenum, it is necessary to move the endoscope forward, rotate it counterclockwise and bend it to the left and downwards.

When using endoscopes with lateral optics, the pylorus is clearly visible from a distance and there is no need to change the position of the distal end. When the device is positioned at the pylorus, only the upper part of the ring is in the field of view and for its complete revision it is necessary to bend the distal end of the endoscope downwards. When passing the pylorus, the end of the endoscope reaches the upper wall of the bulb and its walls are viewed due to rotational movements of the device around its own axis, forward and backward movements and bending of the distal end downwards. The fibroendoscope must be constantly fixed by hand while it is in the bulb of the duodenum, since peristalsis pushes it in the direction of the pylorus. Bile and mucus accumulating in the lumen of the intestine and interfering with the examination are aspirated through the endoscope.

The mucous membrane of the bulb is paler than in the stomach area, with small delicate longitudinal folds that freely straighten out when air is pumped in. The mucous membrane is velvety, has a cellular appearance, juicy, its color is light pink, and a finely looped vascular pattern is sometimes visible on it. An important landmark is the high semilunar fold, located 3-6 cm from the pylorus, which does not disappear when air is pumped in. It seems to separate the bulb from the rest of the duodenum. This place is called the angle of the bulb. Some researchers believe that there is a physiological sphincter in the area of the angle of the duodenal bulb. However, complete closure of the intestinal wall in this place does not always occur, due to which a gap remains through which regurgitation of bile from the descending part of the duodenum occurs. In some cases, during reflux, a small amount of foamy bile is thrown into the ampulla from the distal part of the intestine.

When advancing the endoscope into the descending part of the duodenum, it is necessary to first rotate it clockwise around the axis and bend it downwards, and after reaching the upper angle and bend, on the contrary, rotate it counterclockwise. The cylindrical canal of the descending part of the duodenum is somewhat narrowed in the middle section, where the intestine is crossed by the mesentery of the transverse colon with the middle colic artery located in it. The pulsation of this artery is transmitted through the intestinal wall and can be seen during endoscopy. The mucous membrane of the descending part, like the terminal part of the bulb, forms well-defined circular folds (Kerckring's folds). Closer to the lower bend, they become larger, and the lumen of the intestine expands. The color of the mucous membrane is pink with a yellowish tint, which is due to the bile located on its surface.

Along the posterointernal wall of the descending part of the duodenum there is a longitudinal ridge formed by the common bile duct passing through its wall. This ridge ends in the middle of the descending part with an elevation - a large duodenal papilla of varying size (0.4-1 cm) and shape. Externally, it resembles a polyp on a wide base or resembles a cone or a hemispherical formation. The surface of the papilla is yellow-orange in color, in contrast to the surrounding light pink mucous membrane of the duodenum. In the center of the papilla there is an opening through which the common bile duct and the pancreatic duct open. Sometimes not one, but two papillae are found (minor duodenal papilla). It is not always possible to clearly examine the large duodenal papilla, especially with an endoscope with end optics, since in some cases a fold of the mucous membrane hangs over it. A duodenoscope with a lateral observation tube is more convenient for examining the large papilla. But at the same time, it is inferior in circular examination of the duodenal wall. To move the duodenal papilla from the "profile" to the "face" position, it is often necessary to move the patient to the prone position, and to place the end of the endoscope below the papilla, bending the distal end of the device downwards and to the right.

Examination of the lower horizontal and ascending branches of the duodenum and jejunum is performed by gradually gently moving the endoscope forward and changing the position of the device by rotating it around its own axis and bending the distal end in one plane or another.

At the end of the duodenoscopy, the patient should turn over on his stomach and burp. If a biopsy was performed, then to prevent bleeding from damaged areas of the mucous membrane, 2 ml of a 1% solution of vicasol should be administered intramuscularly. Eating is allowed 1.5-2 hours after the examination.