Chapter 71. Rigid Rectosigmoidoscopy

Rigid rectosigmoidoscopy has largely been replaced by the flexible sigmoidoscope for routine elective screening and diagnostic workups. The rigid rectosigmoidoscope is superior to the flexible sigmoidoscope in measuring distances accurately, examining an unprepared patient, and when trying to work within the bowel lumen, for example when removing foreign bodies. The larger lumen of the rigid rectosigmoidoscope allows for a larger biopsy of lesions where pathology is in question. The cost associated with this examination is less than that for flexible sigmoidoscopy. The rigid rectosigmoidoscope can be purchased in a disposable model that performs well. It is important for a physician who evaluates and treats problems related to the colon, rectum, and anus to be familiar with rigid rectosigmoidoscopy.

The significant anatomy of the anal canal that is necessary to understand and to perform rigid rectosigmoidoscopy is covered in Chapter 70 describing the anatomy for anoscopy (Figures 70-1 & 70-2). The gross anatomy of the colon is reviewed in Figure 71-1A. It is important to be aware of the large folds that impinge on the lumen of the colon called the valves of Houston (Figure 71-1B). These folds must be gently flattened to advance the rigid rectosigmoidoscope and clearly see the proximal side of the valve when looking for pathology. It is also necessary to understand the three-dimensional path followed by the distal colon, rectum, and anus. The direction to follow will be toward the patient's umbilicus for 3 to 5 cm initially. The anus then turns posteriorly as it becomes the rectum and follows the curve of the sacrum. The rectosigmoid junction is reached at 10 to 15 cm, at which point the lumen sharply angulates anteriorly and to the left. Because the scope is rigid and straight, it is necessary to angle the tip of the rigid rectosigmoidoscope toward the lumen of the bowel and then gently flatten the haustra or move the patient's colon so that the lumen is in a straight line.

Many of the indications for rigid rectosigmoidoscopy are the same as those for performing flexible sigmoidoscopy. The rigid scope is more useful when the bowel is not properly prepared, if a bigger biopsy is needed, or if a larger instrument needs to be passed to the last 25 cm. The following is a list of such indications.

The rigid rectosigmoidoscope may be used to evaluate the rectum and sigmoid colon in the office or the Emergency Department. Rectal bleeding can be evaluated in the unprepared patient. It is particularly helpful to determine if stool is mixed with blood when evaluating hematochezia and determining if colonoscopy is indicated. Foreign bodies in the rectum or sigmoid colon can be removed. The rigid rectosigmoidoscope will allow a much larger biopsy and grasping forceps to assist in removing foreign bodies. Traumatic injuries can be assessed. Since the rectum is seldom prepared in the evaluation of a traumatic injury and flexible instruments are unable to clear solid or thick stool, the rigid rectosigmoidoscope is superior in this instance. A sigmoid volvulus can be decompressed using the rigid rectosigmoidoscope to pass a tube to splint the volvulus. It is much easier to suction out a large volume of obstructed material in the colon and leave a large tube with the rigid rectosigmoidoscope. It can be used for surveillance of colon or rectal cancer after a subtotal colectomy. It can be used to accurately measure the distance to rectal lesions from the anus prior to surgery.

There are no absolute contraindications to rigid rectosigmoidoscopy.1 Relative contraindications include severe anal pain that may require general anesthesia, recent surgical anastomosis in the distal 25 cm of the colon and rectum, severe stenosis of the anus or rectum, and peritonitis. This procedure should not be performed by anyone unfamiliar with the equipment and technique as significant complications can occur.

• Phosphate soda enemas
• Rigid rectosigmoidoscope with obturator, air insufflator, eyepiece, and light source
• Suction catheter
• Suction machine or wall suction
• Biopsy forceps
• Long cotton-tipped applicator with a silver nitrate applicator on the opposite end
• Proctoscopy table or examination table
• Protective drape with exam fenestration
• 4 × 4 gauze squares
• Water-soluble lubricant
• Exam gloves
• Impermeable gown
• Instrument stand
• Anoscope, should be available to examine the anal canal if indicated

The rigid rectosigmoidoscope and other required instruments are available in preassembled sterile trays. The tray usually contains the rigid scope, an obturator, a suction catheter, polypectomy snare, and biopsy forceps (Figure 71-2). These trays are available from the Operating Room, hospital central supply, or the surgical clinics. The trays may contain disposable single-use instruments or multiuse instruments depending upon the institution. The remainder of the equipment must be gathered from around the Emergency Department.

The rigid rectosigmoidoscope is a simple instrument (Figures 71-2A & B). The shaft is approximately 30 to 40 cm in length and has 1 cm increments marked on the outside. Attached to the proximal end are an eyepiece, a handle, and an inflation port. The eyepiece swings to open and close over the proximal shaft of the scope. The handle is used to direct and move the scope. Inside the handle is a fiberoptic light source that transmits into the shaft. The insufflator bulb and tubing attach to the inflation port. These are used to insufflate air through the scope and into the colon. The obturator fits within the shaft of the scope. The distal end of the obturator is smooth, occludes the shaft of the scope, and projects 1 to 2 cm distal to the scope.

Explain the risks, benefits, and potential complications of the procedure to the patient and/or their representative. It is also important to explain to the patient what to expect. Discuss the order of examination, the importance of relaxing, the reason for multiple insertions and withdrawals of the rigid rectosigmoidoscope, and what you expect to find. It is important to explain the reason for insufflating air and how this may produce discomfort. Explain that the procedure should not require procedural sedation and that the patient should inform the physician of any discomfort. Assure the patient that the complaint of pain will at least temporarily stop the examination. Perforations are unlikely with a relaxed, cooperative patient. Obtain a signed informed consent for this procedure.

While it is possible to perform a rigid rectosigmoidoscopy with this instrument on an unprepared rectum, more information about the mucosa will be obtained if the bowel has been prepared. Two 4 ounce phosphate soda enemas given at 2 and 1 hours before the examination will give an adequate preparation in most patients. The use of high-volume PEG preparations, saline, or mannitol should be reserved for colonoscopy. There is no need to clean the entire colon. The preparations used for colonoscopy are expensive, involve too much preparation, and cause patient discomfort for the extent of this examination. The judicious use of intravenous sedation may be required in some patients who are anxious.

It is important to check the equipment prior to its insertion into the patient. Open the tray and place the instruments and supplies on the Mayo stand. The eyepiece on the proximal end of the scope should open easily, close easily, and seal against the rigid rectosigmoidoscope. Open the eyepiece and insert the obturator completely within the rigid sigmoidoscope. The handle, including the light source, must be firmly attached. Turn on the light source. The light must be seen coming from the end of the scope. The bulb of the insufflator must pump air into the rigid rectosigmoidoscope and should reinflate after the bulb is released. Liberally lubricate the distal 5 cm of the rigid rectosigmoidoscope and the obturator. Reinsert the obturator into the rigid rectosigmoidoscope.

Disrobe the patient from the waist down. Place the patient in the prone jackknife position on a proctoscopy table if one is available (Figure 71-3A). If the patient is unable to get in this position, or only a routine examination table or stretcher is available, place the patient in the left lateral decubitus or Sims position (Figure 71-3B). The Emergency Physician should be prepared with an impermeable gown and one glove on the left hand and two on the right hand (if right handed). If possible, it is helpful to have someone assist with the remainder of this procedure. Place the fenestrated drape over the patient so that the buttocks are completely exposed (Figure 71-3). Place a Mayo stand or bedside procedure table within reach of the patient's buttocks.

As in anoscopy, it is important to carefully inspect the entire perineum and anal verge prior to the examination. Many types of pathology such as fissures, fistulas, hemorrhoids, condylomata, and dermatologic conditions may be seen at this time.

Digital rectal examination prior to the procedure with a well-lubricated, gloved finger is mandatory. It gives the following advantages. It allows the examiner to find pathology that is better palpated than viewed. It gives the examiner the size and angle of the anal canal. It will allow the examiner to identify if the patient has tenderness that would preclude the examination. It may identify pathology so that the examiner can focus in a specific area. It prelubricates the anal canal, making insertion of the rigid rectosigmoidoscope easier. If the patient has pain from excoriation, 2% lidocaine jelly can be used as a lubricant and will provide some local anesthesia. This examination is usually performed with the right hand. Remove the extra glove from the dominant hand before picking up the rigid sigmoidoscope. This prevents the contaminated glove from holding the scope near the Physician's face.

Stand to the left side of or directly behind the patient. Place the left, or nondominant, hand on the patient's buttocks (Figure 71-4A). Grasp the handle of the rigid rectosigmoidoscope with the right, or dominant, hand. Place the right thumb on the obturator to keep it properly seated (Figure 71-4B). Spread the buttocks with the left hand (Figure 71-4). Gently and slowly insert the rigid rectosigmoidoscope into the anus and aimed toward the patient's umbilicus. Advance it to the 5 cm mark.

Support the rigid rectosigmoidoscope at the anus with the left hand (Figure 71-5A). This is necessary so that if the patient moves, the instrument will move with the patient. Remove the obturator and place it on the Mayo stand. Close the eyepiece and insufflate air into the rectum.

One must control the insertion and direction of the rigid rectosigmoidoscope with the right hand while stabilizing it with the left hand (Figure 71-5A). Continue to slowly advance the rigid rectosigmoidoscope under direct viewing while simultaneously insufflating air to distend the walls of the colon (Figure 71-5A). The anal canal is approximately 4 to 5 cm in length (Figure 71-6). The rectum will be seen to turn somewhat posteriorly and follow the hollow of the sacrum (Figure 71-5B). Moving the right hand and the rigid rectosigmoidoscope anteriorly will direct the tip posteriorly (Figure 71-6B). Use the left hand as a fulcrum to help maneuver the distal tip of the rigid rectosigmoidoscope to follow the lumen of the rectum (Figure 71-6). The sigmoid colon can also be identified by the presence of transverse folds that are lacking in the rectum. The rectosigmoid junction is approximately 16 cm from the anus and can be seen when the lumen turns anteriorly and to the right (Figure 71-6C). It is necessary to use the rigid rectosigmoidoscope to gently straighten the colon while completely inserting the instrument to a depth of 25 cm. It is important to view the bowel lumen at all times. Never advance the instrument blindly as this may cause a perforation.

Maintain communication with the patient, inform them of what is happening, and elicit the status of their comfort. Open the eyepiece if it becomes clouded with moisture and wipe it with dry gauze so the view is kept clear. Do not keep your face near the eyepiece when opening the eyepiece. The insufflated air may forcefully expel stool and secretions. The bowel must be reinflated when the eyepiece is reclosed.

After the rigid rectosigmoidoscope is advanced to 25 cm, or as far as the patient will allow, slowly remove it with a circular motion (Figure 71-7). View the mucosa while removing the rigid rectosigmoidoscope in a circular motion. This flattens out the haustra and valves of Houston so that the entire mucosal surface can be viewed. Attempt to keep at least 50% of the colonic lumen in view at all times. Open the eyepiece just prior to completely removing the rigid rectosigmoidoscope to release as much of the insufflated air as possible. This will make the patient more comfortable.

The viewing window, which seals in the air, must be opened if it is necessary to biopsy or to grasp something. This will result in the collapse of the rectum and loss of view. It is important to place the tip of the rigid rectosigmoidoscope over the area in question so it will stay in the examiner's view. The obturator should be reinserted if it is necessary to reinsert or readvance the rigid rectosigmoidoscope.

Completely and carefully inspect the colonic mucosa. Note the presence, location (i.e., anterior, posterior, left, and right), and the depth of any bleeding, diverticulum, fistulas, hemorrhoids, lesions, masses, mucosal irregularities, and/or polyps. Document any findings in the medical record.

The patient may be discharged home after the procedure if there are no complications and there is no other reason to admit them to the hospital. They may experience mild discomfort, flatus, and spotting of blood in the stool for several hours. Instruct the patient to immediately return to the Emergency Department if they develop a fever, abdominal pain, nausea, vomiting, bright red blood per rectum, or if they have any concerns. Follow-up should be arranged with a Family Practitioner, Internist, Gastroenterologist, or Surgeon depending upon the findings of the examination.

The primary complication of rigid rectosigmoidoscopy is perforation of the rectum or sigmoid colon. Air insufflation may cause an existing perforation, such as may be associated with diverticulitis, to burst, and is the reason one should not perform this examination if the patient has existing peritonitis. Perforation can occur with forceful insertion of the instrument without viewing the colonic lumen or if the patient moves suddenly and the scope is not supported with the left hand. Perforation may also occur with instrumentation in related procedures, such as a biopsy. Perforation should be almost nonexistent if one supports the scope well, views the colonic lumen while advancing the scope, and listens to the patient about complaints of pain.

Minor complications may occur. Trauma to the mucosa from the rigid rectosigmoidoscope or instrumentation in related procedures, such as a biopsy, can result in minor bleeding that is usually self-limited. Brisk bleeding can be controlled by the judicious use of a silver nitrate matchstick. Bacteremia may occur in up to 10% of patients. Antibiotic prophylaxis for endocarditis should be administered, if indicated, prior to the procedure. Mild abdominal discomfort and flatus can last a few hours.

Rigid rectosigmoidoscopy is inexpensive, easy to perform, and useful in bowels with poor preparation or where a wider access is needed. These characteristics make the instrument useful in many indications. With proper training and understanding of the anatomy, this examination is well tolerated by the patient and will be useful to diagnose and treat many colonic and rectal problems.