CHAPTER 103 Flexible Sigmoidoscopy

The flexible sigmoidoscope has become a standard instrument in the primary care physician’s office to detect and prevent colorectal cancer (CRC). Approximately 150,000 cases of CRC occur each year in the United States, with 55,000 deaths. It is the second-highest cause of cancer deaths in this country. The sigmoidoscope may be used to decrease morbidity and mortality of CRC either through early detection or by preventing it by removing precursor polyps. Well-designed, case-controlled studies have demonstrated the effectiveness of using sigmoidoscopy to screen for CRC, and sigmoidoscopy combined with annual fecal occult blood testing (FOBT) can be expected to yield an 80% reduction in mortality from CRC. In addition to screening for CRC, the sigmoidoscope is a valuable tool in evaluating symptomatic patients.

All major sources of guidelines for preventive medicine recommend screening for CRC, and physicians who fail to perform or recommend screening face medical-legal issues. Debate continues, however, regarding the best method of screening for this cancer. FOBT and sigmoidoscopy continue to be the most commonly used methods of screening for CRC in average-risk patients. Screening colonoscopy is becoming more popular, especially in high-risk patients, but direct evidence of mortality reduction is lacking. An extensive review of the literature (Frazier and colleagues, 2000) concluded that the best and most cost-effective method for CRC screening in average-risk patients was flexible sigmoidoscopy every 5 years, along with FBOT every year. In another screening model, colonoscopy once every 10 years was more cost effective than sigmoidoscopy every 5 years, but this model did not combine sigmoidoscopy and FOBT screening (Sonnenberg and colleagues, 2000). A recent study demonstrated that screening flexible sigmoidoscopy performed only once on people between ages 55 and 64 years, conferred a substantial (31% reduction in mortality) and long lasting protection from colorectal cancer (Atkin and colleagues, 2010).

Studies have concluded that patients will undergo whatever test their physician recommends. Unfortunately, in 2004 only 57% of adults in the United States had been screened by currently recommended methods. It is imperative for physicians to implement and encourage proper screening.

Indications

• Screening: The American Society of Gastroenterology (ASGE), the American Cancer Society (ACS), the American College of Physicians (ACP), the National Cancer Institute (NCI), the American College of Obstetricians and Gynecologists (ACOG), the American Academy of Family Physicians (AAFP), and the United States Preventive Services Task Force (USPSTF) all recommend routine screening of not-at-risk patients 50 years of age and older for colon polyps and colon cancer. Note that no one is considered at “low risk” for screening purposes. The 2008 clinical summary of the USPSTF recommendations for screening for CRC are included in Table 103-1. (Also see “Colon Cancer Screening Options Vary” online at www.expertconsult.com.)

• Surveillance after previous polypectomy.

• Surveillance for effectiveness of treatment for ulcerative colitis/Crohn’s disease.

• Abdominal pain.

• Rectal bleeding (bright red or occult).

• Constipation or diarrhea.

• Persistent change in usual bowel habits.

• Unexplained weight loss, fever, or anemia.

• Suspected inflammatory bowel disease or antibiotic-associated colitis.

• Anorectal symptoms. (Note, however, that hemorrhoids alone are not an absolute indication for flexible sigmoidoscopy or air-contrast barium enema [ACBE] and must be put into the context of the entire patient history and examination. Medicare does not reimburse for an endoscopy procedure with the sole diagnosis of “hemorrhoids.”)

• Evaluation of radiographic abnormality or to confirm a radiologic finding with a biopsy.

TABLE 103-1 Screening for Colorectal Cancer: Clinical Summary of U.S. Preventive Services Task Force Recommendation*

Although flexible sigmoidoscopy may be used for the initial evaluation of some complaints, it is limited by the amount of colon it can evaluate. Certainly with selected symptoms, if the sigmoidoscopy is negative, a more extensive work-up is still indicated. Thus, for many patients, obtaining a colonoscopy as the primary procedure may be more cost effective. On the other hand, availability and cost concerns may lead to sigmoidoscopy as the initial procedure of choice.

Because of redundant loops of sigmoid colon and because the insertion tube that is used for barium enema can obscure a lesion, flexible sigmoidoscopy (or, at the minimum, anoscopy) is generally needed along with ACBE if the entire bowel must be visualized. Individual circumstances dictate whether a flexible sigmoidoscopy alone or in conjunction with an ACBE is needed.

Contraindications

Equipment

The flexible sigmoidoscope is available as either a fiberoptic endoscope or video endoscope. Although the fiberoptic scope has been the most commonly used version, the video sigmoidoscope is state of the art, using computer chip and video technology. The image from the tip of the scope is transmitted to a video monitor. This equipment facilitates videotape recording, sound narration, and other patient information storage.

The following basic equipment is necessary to carry out routine flexible sigmoidoscopy:

• 60- to 70-cm-long submersible scope consisting of the body with controls (Fig. 103-1) and the shaft of the scope with tip and apertures (Figs. 103-2 and 103-3)

• Light source (most have air supply and wash bottle attached; Fig. 103-4)

• Suction apparatus (Fig. 103-5)

• Biopsy forceps (Fig. 103-6)

• Water-based lubricant (e.g., K-Y Jelly)

• 4 × 4 gauze pads

• Nonsterile gloves

• Shielded glasses

• Anoscope (Ives slotted anoscope preferred; see Chapter 98, Anoscopy)

• Basin of soapy water (immediately on completion of the procedure, suction water through the scope, then place the scope in the basin)

• Formalin jars

• Disinfecting cleanser

• Nursing assistant (to assist with equipment and procedure)

• Video unit and monitor (for video endoscopes only)

Figure 103-1 Control head and body of the fiberoptic sigmoidoscope.

Figure 103-2 A, Tip of the sigmoidoscope. B, Tip lubricated with K-Y Jelly.

Figure 103-3 Schematic diagram of a fiberoptic sigmoidoscope.

Figure 103-4 Light source with air supply.

Figure 103-5 Suction apparatus.

Figure 103-6 Biopsy forceps. A, Relative size of forceps. B, Control handle. C, Stabilizing needle. D, Biopsy forceps protruding from end of scope, closed on a piece of paper.

(Courtesy of John L. Pfenninger, MD, The Medical Procedures Center, PC, Midland, Mich.)

Preprocedure Patient Preparation

A good history (present and past) is essential before performing any procedure. Not only should the patient’s overall medical risk status be determined, but the risk for CRC and any associated symptoms must be assessed to ensure that flexible sigmoidoscopy is indeed the proper procedure and that there are no contraindications to performing it.

Flexible sigmoidoscopy in most patients is easily performed in less than 15 minutes. However, for some patients the very thought of a tube in the rectum provokes anxiety, apprehension, and reluctance. This makes it necessary for the clinician to reassure the patient and allay apprehension and anxiety with a thorough explanation. Use simple words with the aid of charts and figures. Explain the procedure to be performed, why and how it will be done, and the possible complications. The components of this patient education process include the following:

1 Bowel cleansing instructions (usually two enemas; see the sample patient education handout online at www.expertconsult.com)

2 Equipment used

3 Anatomy of the colon

4 Explanation of procedure

5 Discomfort experienced during the procedure (“crampy distention,” especially at the second curve around 40 cm and with insufflation of air)

6 Complications that are remotely likely (e.g., perforation, bleeding)

7 Possible diseases likely to be detected

8 Biopsy technique, if needed

9 Whether photography or videotape will be used

10 Management of any findings

11 The need to continue all prescribed medications

It is highly advisable to have the patient sign the informed consent form for this procedure after reading the patient information materials. (See the sample patient education handout and consent form online at www.expertconsult.com.)

Flexible sigmoidoscopy is well tolerated by the vast majority of patients. Mild analgesia or sedation, whether given orally or intramuscularly, is rarely needed. Oral diazepam or ibuprofen can be used as needed in the individual situation. Atropine 0.5 mL intramuscularly can be given for those who have a tendency to faint or experience vasovagal symptoms.

Patient Bowel Preparation

Simple enemas (tap water, Phospho-Soda) administered until clear fluid is passed is the only requirement. This usually entails two enemas (occasionally three) 30 to 60 minutes before the procedure. Patients are allowed to take their medications and eat normally. If the patient tends to be constipated, a laxative should be given the day before the procedure. Keeping the regimen simple is more likely to ensure compliance.

In one study (Sharma and Chockalingham, 1997), two Fleet enemas given on arrival to the endoscopy suite were compared with one bottle of magnesium citrate and two Dulcolax tablets the evening before the procedure. Both patients and endoscopists preferred the oral method. Another study (Manoucheri and colleagues, 1999) showed no difference in results comparing four bowel preparation regimens.

Antibiotic Prophylaxis

Antibiotics for subacute bacterial endocarditis prophylaxis are no longer recommended for lower endoscopy procedures with or without the performance of biopsies, even in high-risk patients (see Chapter 221, Antibiotic Prophylaxis).

Technique

A specific terminology has developed around the procedure of flexible sigmoidoscopy. Box 103-1 summarizes this “language” that must be understood before learning the procedure.

1 Before beginning the procedure, all functions of the endoscope must be checked. The light source should be turned on and clarity of view confirmed. White balance must be performed for videoscopes. The “button” to insufflate air and the water button are the same (see Fig. 103-2). Just covering the air/water button introduces air, whereas pushing it down all the way ejects a small amount of water to clean the lens. This button is the one closest to the patient. The second button, closer to the eyepiece, is for suction. Remember: the button closest to the patient puts things in and is usually colored blue, the button closest to the endoscopist “sucks” things out and is usually colored red. Air function is confirmed by inserting the scope tip in water and seeing bubbles when the air port is occluded. Suction is confirmed by suctioning a small amount of water through the endoscope. Tip deflection is checked by rotating both control wheels fully in both directions while observing and feeling for free movement. After checking all functions, the fiberoptic unit may be turned off temporarily. Many video endoscopes have to be white balanced each time they are turned off, so leaving them on is preferable.

2 If sedation is to be used, record the patient’s temperature, pulse, respiration, blood pressure, and results of heart/lungs auscultation and abdominal examination.

3 Position the patient in the left lateral Sims’ position (see Chapter 97, Clinical Anorectal Anatomy and Digital Examination, Fig. 97-2).

4 The endoscopist and assistant should wear nonsterile gloves on both hands. Double glove the right hand. (Remove the extra glove after the tip has been lubricated, the rectal examination performed, and the scope initially inserted.) Place the body and shaft of the scope on the cart. Lubricate the distal 3 to 4 cm of the shaft tip with K-Y Jelly (avoid the lens). Notice where the dials are positioned when the shaft is completely straight.

5 Separate the gluteal folds laterally with the hands to expose the anal area and the anal aperture for inspection. Perform a digital rectal examination with K-Y Jelly or lidocaine ointment to ensure there is no obstruction or stool in the anal canal. In male patients, examine the prostate carefully. A painful examination should alert the endoscopist to a fissure, proctitis, or colitis. The examination is uncomfortable but should not be painful if it is done gently. The digital examination helps to relax the sphincter and lubricates the anal canal. (See Chapter 97, Clinical Anorectal Anatomy and Digital Examination.)

6 Now hold the body of the scope in your left hand (Fig. 103-7). Hold the end of the scope shaft in the right hand, and, with the index finger alongside and stabilizing the very end, gently insert it. Hold the tip at an oblique angle pointing posteriorly, and stretch the sphincter as the tip is slipped into the anal canal. The shaft tip can be blindly inserted 10 to 20 cm. Stop when resistance is felt. Remove the second glove on the right hand.

7 With the distal 10 cm or more of the scope in the anal canal, switch on the light source, air, and suction, if these had been turned off. Check the view in the eyepiece or on the video screen.

8 Keep holding the body of the scope in your left hand so that your thumb controls the large dial and your index finger controls the suction, irrigation, and air valves. Hold the shaft and advance it with your right hand, which is also available to control the small dial. Alternatively, an assistant may advance the scope, and you may use your right hand to manipulate the dials. The assistant must be cautioned never to advance the scope against resistance and to advance the scope only when told to do so. This latter method is easier and faster for some physicians, but solo operation may allow better coordination of movements of the shaft and deflecting tip. Use the technique that accomplishes the procedure in the fastest manner with minimal patient discomfort.

9 Insufflation advance technique

• Air is needed to maintain patency of the lumen and to obtain a clear view adjacent to the tip and a few centimeters beyond. Remember, the air button and water button are the same. Just covering the button introduces air, whereas pushing it down all the way diverts air into the water bottle and ejects a stream of water across the lens to clean it. A sufficient amount of air must be used to expand the bowel, but too much air may cause cramping or, in extreme cases, even perforation. Excess air also lengthens the bowel and may cause sharper bends. Use patient comfort as a guide. With a clear view ahead, gently advance the shaft forward. The scope is usually advanced up to 15 to 18 cm without difficulty. There are three “valves” that are encountered in the rectum: the valves of Houston. These are semilunar in shape, are not really “valves,” and are located 6, 9, and 12 cm from the anal verge. Negotiating advancement into the rectosigmoid can be hampered by these folds, and the tip needs to be deflected away from the fold and toward the lumen to avoid redout or whiteout. The clinician can get “lost” in the vast arena of the rectal vault and have difficulty in locating the rectosigmoid orifice. This is more likely if too much air is insufflated, which causes the ampulla to expand upward.

• There is always a question of how much air to use. The answer: enough! Generally, as long as the patient is not sedated, he or she will tell if too much pressure is being generated. Some clinicians are too timid and will never see the lumen if “enough” air is not used.

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