Flexible Sigmoidoscopy
In advance of the procedure, check to make sure that all the required equipment is functional, especially the air/water and suction valves. Check the quality of the image on the video monitor, and use the controls on the processor to ensure correct white balance on the display.
Put on gloves and a protective apron. Perform a perianal inspection and a digital rectal examination (DRE) using a water-based lubricant. The DRE should include evaluation for any masses or hemorrhoids, as well as evaluation of the prostate in men.
Lubricate the distal 10-20 cm of the shaft of the sigmoidoscope, taking care not to smear the lubricant on the lens at the distal end, and insert the scope gently into the anus under direct vision. Once the shaft's end is inside, shift attention to the video monitor. Insufflate air, and bring the lumen of the rectum into view, using the control knobs on the handle.
The three semilunar valves are visible in the rectum (see the image below). Advance the endoscope gently, keeping the lumen in view; to navigate, apply torque (by twisting the shaft) and use the up/down knob.
Approximately 20 cm from the anal verge, the rectosigmoid junction comes into view. Negotiate it carefully, taking care not to apply any undue pressure. The sigmoid colon is then entered (see the image below). This structure contains multiple turns; take your time in passing through them. Try to minimize air insufflation. Water infusion from a foot-controlled pedal may be used.
Because of the way in which the colon curves, the endoscope tends to form a loop as it passes through the sigmoid colon toward the descending colon. Excessive loop formation may result in pain or discomfort for the patient and may increase the risk of perforation. To reduce a loop, pull back the shaft of the endoscope while simultaneously suctioning the air from the lumen. Torquing toward the right while pulling back may also help straighten the sigmoid colon.
The descending colon appears as a straight tube with a circular lumen (see the image below). Keep advancing.
The splenic flexure (see the image below) may have a slightly dark appearance because of the adjacent spleen. It may also contain a small pool of fluid (with the patient in the left lateral position). Beyond the flexure, the triangular appearance of the transverse colon is visible. The splenic flexure marks the distal limit of a sigmoidoscopic examination.
Begin to withdraw the endoscope, taking care to examine the colonic mucosa carefully as you do so. Any abnormalities (eg, polyps, erythema, ulceration, masses, or diverticula) should be noted. Depending on the skills of the endoscopist, biopsies or polypectomies may be undertaken; otherwise, these patients may be referred to a gastroenterologist for a full colonoscopy, as well as for therapeutic maneuvers such as polypectomy.
Once the scope is back in the rectum, undertake retroflexion to ensure that no distal rectal lesions have been missed and to look for any internal hemorrhoids. Withdraw the endoscope to the anal canal, which is distinguished from the rectum by the change in the color of the mucosa and the narrowing of the lumen, and take the following three actions simultaneously:
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Turn the big knob all the way to the up position
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Torque the shaft to the right
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Push the shaft in
When these actions have been taken, a retroflexed view should become available as the endoscope's shaft becomes visible on the screen (see the image below). Insufflation of air insufflation and adjustment of the left/right knob can further improve the view.
Next, turn the knobs back to the neutral position; the view should be forward before the endoscope is extracted. In addition, suction as much air as possible before removing the endoscope.
Throughout the examination, take photographs of any abnormal findings. If everything looks normal, take photographs of the most distal extent of the examination, as well as of the retroflexed view in the rectum, for documentation purposes.
The endoscopy report should include details on any abnormalities found. It should also include the indication for the procedure, the medications administered (if any), the extent of the examination, any intraprocedural complications that develop, the details of any diagnostic or therapeutic maneuvers performed, and the follow-up plan.
The videos below depict various disease states visualized via flexible sigmoidoscopy.
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Splenic flexure as shown by flexible sigmoidoscopy.
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Descending colon as shown by flexible sigmoidoscopy.
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Sigmoid colon as shown by flexible sigmoidoscopy.
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Rectum as shown by flexible sigmoidoscopy.
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Rectum (retroflexed view) as shown by flexible sigmoidoscopy.
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Flexible sigmoidoscopy: inflammation due to diverticulitis in sigmoid colon. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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Flexible sigmoidoscopy: inflammation of rectum (proctitis) in patient who had surgery with J pouch created. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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Flexible sigmoidoscopy: pseudopolyps in colon. This is common in inflammatory bowel disease (eg, Crohn disease or ulcerative colitis). Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
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Flexible sigmoidoscopy: segmental colitis associated with diverticulosis (SCAD). Inflammation is apparent in setting of diverticulosis in sigmoid colon. Video courtesy of Dawn Sears, MD, and Dan C Cohen, MD, Division of Gastroenterology, Scott & White Healthcare.
