Cecal intubation rates can also be influenced by colonoscopist-related factors like individual practitioner experience. A landmark population-based study evaluated over 330,000 patients undergoing index screening colonoscopy in Canada and showed that the endoscopists in the lowest volume quintile had a 29% colonoscopy failure rate [3]. This puts into perspective the impact of individual practitioner experience as it relates to the success of colonoscopy. Other clinician factors relating to cecal intubation rate include skill, manual dexterity, and technique.

Many of the potential problems related to completing a colonoscopy can be avoided by using sound insertion techniques including repeatedly shortening the colon and reducing loops along the shaft of the scope. Hooking a mucosal fold by deflecting the tip of the colonoscope anchors the position of the tip of the scope and then withdrawing the scope with a clockwise torque reduces loops and shortens the colon by telescoping the colon up onto the shaft of the scope. In situations where attempts at clockwise loop reduction are not effective, withdrawing the scope using counterclockwise torque may facilitate scope advancement. This maneuver can be especially helpful in negotiating the proximal transverse colon. As the colonoscopist attempts to pleat the colon over the scope, it is common to first lose some ground as the colon slides off of the scope. With continued efforts to shorten the colon, the colonoscopist should be reassured that this ground will be regained and the scope will advance.

Failing to repeatedly withdraw sufficiently and reinsert is thought to be the most common error made when attempting colonoscopy through a redundant or floppy colon. In a difficult colonoscopy with looping or redundancy, repeated efforts to pleat the colon onto the scope are often required in order to advance the colonoscope. The goal is to achieve at least “one-to-one” transmission of shaft movement to the tip of the device. Deliberate to-and-fro movement of the scope (jiggling) or gentle shaking of the colonoscope (dithering) can also pull the colon onto the shaft of the instrument. In situations where the lumen proximal to the tip of the scope is not well visualized, these movements can also help the colonoscopist find the lumen. The importance of proper technique cannot be overemphasized, especially when you consider that the majority of repeat colonoscopies after a failed colonoscopy are completed using routine colonoscopes and proper technique [4].

Hooking the colon and withdrawing scope, as described earlier to reduce looping, can also be helpful when negotiating an angulated area where the view is limited and the proximal lumen is not seen well. Blind insertion (“slide by”) in this situation should be avoided as this could be traumatic. Recognizing that the colon, to some degree, is mobile; this maneuver manipulates the anatomy and may allow better visualization of the lumen and safe scope advancement. This manipulation is also helpful for finding the lumen along a segment of severe diverticulosis.

Right-handed torqueing of the shaft of the instrument adds additional degrees of freedom of motion to the colonoscope and affords the colonoscopist finer control of the tip of the device rather than relying solely on the control dials to navigate in the “X” and “Y” axes. This is especially useful when negotiating through the rectosigmoid junction or through an area of diverticulosis or tortuosity. This right-handed maneuvering, together with the torqueing used to reduce loop formation, can, over the course of a difficult insertion, cause the colonoscope shaft to assume a contorted shape. The more convoluted the instrument, the more rigid the shaft becomes and the harder it is to control the tip of the instrument and to advance the scope through the colon. Gently rotating the shaft counterclockwise to allow the scope to assume a more neutral configuration relieves the rigidity associated with a misshaped instrument and permits further scope advancement.

Controlling and correcting the degree of gaseous distension is also helpful during insertion. It is important to avoid overinsufflation, as this tends to elongate the colon and make insertion more difficult and may lead to barotrauma. An overly distended colon can be difficult to telescope over the colonoscope while suctioning out excess gas facilitates insertion particularly when coming across the transverse colon.

Liberal use of external pressure can limit loop formation and facilitate cecal intubation and changing out of the left lateral position can expedite advancement of the scope (Fig. 11.2). The benefit of an experienced assistant applying appropriate external pressure cannot be overstated. Supination can help negotiate a difficult hepatic flexure and right lateral positioning, an underutilized maneuver, can help move from the ascending colon into the cecum. Rarely, pronation may permit further advancement of the colonoscope by using the weight of the patient to fix the colon in place.

Another readily available way to potentially increase the success of cecal intubation is changing out the colonoscope. To overcome the looping problem during colonoscopy, variable stiffness colonoscopes have become widely available even though these scopes have not been shown to reliably improve cecal intubation rates . In theory, increasing shaft rigidity transmits the force of insertion to the tip of the scope by reducing bowing and loop formation. In terms of using thinner, more flexible colonoscopes, the literature supports the idea that in patients who fail colonoscopy due to angulation, especially women who have had a hysterectomy, a thinner scope may improve the chances of successful colonoscopy. A pediatric scope with decreased cross-sectional surface area as compared with an adult scope can overcome angulation, fixation, or tortuosity and should be available for use in the setting of a difficult colonoscopy. In cases of severe angulation, a thinner, more flexible upper endoscope may be useful. The shorter length of these upper scopes, however, can limit the extent of insertion. Changing out the upper scope for a longer pediatric colonoscope using a guidewire exchange technique , after traversing the angulation, may be helpful.

In the midst of a difficult colonoscopy, confirming cecal intubation is essential to avoid mistakenly concluding that a complete colonoscopy has been performed. This may be confidently accomplished by inspecting the cecal strap (crow’s foot), appendiceal orifice, and ileocecal valve. Intubating the ileum, while not required for a complete colonoscopy, can further confirm the anatomy and the true extent of the examination performed. Due to the ptosis of a redundant transverse colon, transillumination in the right lower quadrant is not sufficient evidence that the scope has reached the cecum. The colonoscopist should be wary of relying only on pattern recognition of a thickened mucosal fold as evidence of reaching the ileocecal valve as a bend near the hepatic flexure colon can mimic the appearance of the valve and spiraling of the colon due to prior abdominal surgery can cause the wall of the colon to appear like the confluence of the tenia in the caput (the fool’s cecum).

Antispasmodics and using CO₂ insufflation instead of ambient air have also been evaluated and have not been shown to reliably improve cecal intubation rates or scope insertion times during a difficult colonoscopy.

Another consideration that may prove helpful when performing a difficult colonoscopy includes using warm water instead of ambient air insufflation during insertion (“submarine” colonoscopy). Water immersion techniques have been studied to possibly improve colonoscopy success rates and to decrease the discomfort of the exam. In theory, instilling water into the sigmoid colon, with a patient in the left lateral position, uses gravity to straighten the colon and reduce angulation, facilitating insertion with less looping. This method may also minimize the degree of colon elongation associated with conventional air insufflation allowing the colonoscopist to use less length of the colonoscope and, in theory, reduces the spasm associated with air insufflation. Water immersion has been studied mostly in the setting of unsedated colonoscopy. Residual material mixed with the infused water can impair visualization and cause this method to fail. It is important that the immersion is instituted from the onset, as water use once the scope is well underway may not prove to be as effective.