Total colonoscopy has become common practice, and it is less frequently difficult to complete a total colonoscopy by inserting an endoscope into the cecum. In some patients, however, even skilled endoscopists give up inserting the endoscope into the cecum because of its difficulty.
As described in Chapter 5, what makes insertion of a colonoscope and other endoscopes difficult is the stretching of the intestine that has formed bends or loops. The endoscope tip does not advance because endoscope insertion is translated into stretching the intestine. Moreover, intestinal stretching causes discomfort to the patient (Fig. 12.1.1).
Representative conditions that make insertion of a colonoscope difficult include adhesions in the sigmoid colon and the transverse colon. The presence of an adhesion does not necessarily mean an obstacle to colonoscopic insertion. When an adhesion complicates the anatomy, however, it makes insertion difficult.
Adhesions in the sigmoid colon often result from appendectomy, gynecologic surgery, peritonitis, and colonic diverticulum; and insertion of a colonoscope is difficult when an adhesion of the sigmoid colon to the right lower abdomen precludes straightening the sig-moid colon. The endoscope tip may be advanced into the descending colon with difficulty but not beyond the splenic flexure because the sigmoid colon is only stretched and not straightened (Fig. 12.1.2a).
Adhesions in the transverse colon are often associated with cholecystectomy, gastrecto-my, or peritonitis; and colonoscope insertion is difficult when adhesion of the transverse colon to the lower abdomen precludes straightening the transverse colon. The endoscope may be advanced into the middle of the transverse colon but not beyond the hepatic flexure because the sagging transverse colon cannot be lifted up to straighten it, resulting in stretching of the transverse colon (Fig. 12.1.3a).
When adhesions in the sigmoid colon or transverse colon preclude straightening the intestine through which the double-balloon endoscope has advanced, the balloon at the tip of the overtube grips the intestine from inside, and the intestinal tract over the overtube may form a loop or bend but not stretch. For this reason, insertion of the endoscope shaft is effectively transmitted to the endoscope tip without stretching the intestine and allows deep
Fig. 12.1.2. Adhesion in the sigmoid colon a b
Fig. 12.1.2. Adhesion in the sigmoid colon a b b advancement of the endoscope (Figs. 12.1.2b, 12.1.3b). Inhibiting any stretching of the intestine substantially reduces the patient's discomfort.
The following is a specific method of insertion in the presence of an adhesion in the sigmoid colon (Fig. 12.1.4). First, the endoscope with a deflated balloon at the tip is inserted through the anus without specific efforts for straightening. The endoscope is advanced until further insertion is difficult (in most cases, up to the sigmoid-descending colon junction). Then the balloon at the endoscope tip is inflated to secure the endoscope, and an overtube with a balloon attached is inserted along the endoscope. After the balloons on the endoscope and the overtube are inflated, the entire endoscope is pulled back with the endoscope tip left in position. This procedure does not necessarily require straightening of the sigmoid colon. Because the overtube with the balloon prevents stretching, an angulated sigmoid colon does not interfere with the endoscope insertion. After the balloon at the endoscope tip is deflated, the endoscope is advanced again, and similar procedures are repeated before the splenic flexure and the hepatic flexure. This strategy allows the endoscope to reach the cecum without unnecessary stretching of the sigmoid colon that is impossible to straighten.
The following is a specific method of insertion in the presence of adhesions in the transverse colon (Fig. 12.1.5). As described for the presence of an adhesion in the sigmoid colon, the balloon is used to insert the endoscope until it reaches the splenic flexure. After the tip of the overtube with the balloon attached is secured just before reaching the splenic flexure, the endoscope is advanced beyond the splenic flexure until further insertion is difficult. Then the balloon at the endoscope tip is inflated to secure the endoscope, and the overtube with the balloon attached is inserted along the endoscope. After both balloons (at the endoscope and the overtube) are inflated, the entire endoscope is pulled back with the endoscope tip left in position. Thereafter, the balloon at the endoscope tip is deflated, and the endoscope is further advanced. When insertion is difficult at the hepatic flexure or other locations, a similar procedure may be attempted. This strategy allows the endoscope to reach the cecum without stretching the transverse colon that is impossible to straighten.
An actual case is presented here. A 70-year-old man with previous cholecystectomy was found to have polyps in the ascending colon and the transverse colon on barium enema examination. A skilled endoscopist performed conventional colonoscopy but failed to advance the scope beyond the splenic flexure because the sigmoid colon with an adhesion was not straightened but only stretched. On another day, a second experienced endoscopist performed unsuccessful colonoscopy. The double-balloon method later allowed us to advance the endoscope beyond the splenic flexure into the transverse colon, with the sig-moid colon left angulated. Although an adhesion again precluded straightening the transverse colon, the overtube with a balloon attached was inserted into and secured in the trans-
verse colon, enabling the endoscope to advance beyond the hepatic flexure into the cecum and finally the terminal ileum (Fig. 12.1.6). The polyps in the ascending colon and the transverse colon found on barium enema were successfully resected, and the examination and treatment were completed without patient discomfort.
Fig. 12.1.6. A case with adhesions at the sigmoid colon and the transverse colon
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