Full-thickness electrocoagulation can result in postpolypectomy syndrome or perforation, which will be discussed at length later in the chapter. It is not recommended to perform biopsy with “hot” biopsy forceps to avoid thermal spread. In addition, when it is necessary to use a “hot” snare, the polyp should be retracted away from the bowel wall and into the lumen prior to anticoagulation being applied to maximize the distance between the current in the submucosa and the serosa [6]. Additionally, the saline lift technique , during which saline is injected into the submucosa prior to polypectomy, may aid in preventing thermal spread by expanding the submucosal layer [7].

Looping of the scope in the colon is a major obstacle to successfully completing colonoscopy and a potential cause of colonic perforation. Looping is caused by a mobile mesentery in the sigmoid and transverse colon. When a loop is formed, paradoxical movement of the scope can occur, which is noted when the tip of the scope moves backward while the endoscopist is pushing the scope forward. There are several techniques to avoid looping and to reduce the loop once one has formed. Initially, during scope insertion , the endoscopist should endeavor to use primarily clockwise rotation. In this fashion, the mobile sigmoid is held against the pelvic sidewall. This minimizes the risk that a medially bent sigmoid can loop with a mobile, narrow-based mesentery. In addition, starting at the second rectal valve, the endoscopist can torque the scope clockwise while applying suction and pulling the scope backward. In doing so, the colon is being intussuscepted onto the colon, and rather than a large omega loop forming, the colon is straightened out onto the scope. This maneuver is repeated every 10–20 cm until the hepatic flexure is reached. A similar maneuver can be used to reduce an already formed loop. The scope is torqued clockwise while applying suction and pulling back until the loop is reduced. When the loop is reduced, paradoxical motion is eliminated, and the scope freely advances forward. There is always a potential to lose ground when attempting to reduce a large loop when the scope regresses further than the loop when pulling back. To avoid this, it is important to reduce the loop as the scope is advanced and avoid making a large loop. Additionally, loops in the scope outside the colon can form and can be addressed by rotating the scope outside the colon.

Another method to decrease looping as the scope is advanced is to irrigate and fill the sigmoid colon with water as the scope is advanced. The colon being weighed down with the water makes it less likely to form a large loop. Abdominal pressure can also be important to stabilize an already formed loop and enable the forward passage of the scope, especially in the right colon. The assistant applies pressure in the left abdomen downward toward the stretcher and the patient’s pelvis. This functions by “pinning” the sigmoid colon laterally, preventing torque on a mobile, broad, mesenteric pedicle. Additionally, a second hand can apply pressure upward to stabilize the transverse colon if needed. When a loop forms, it can cause pain or discomfort in the moderately sedated patient. It is important to note this pain and attempt to reduce the loop. Unfortunately, in the heavily sedated patient, this pain is often not apparent, and large loops and painful maneuvers can be underestimated. This underscores the balance of optimizing patient comfort without compromising patient safety and the importance of avoiding over sedation during colonoscopy.

The lumen should be visualized at all times when advancing the scope. There should be no blind pushing of the scope around turns to avoid perforation. When approaching a difficult and tight turn, pulling back on the scope rather than pushing forward can help visualize the lumen and allow the scope to be advanced safely. A pediatric colonoscope can often be advanced around tight turns more easily than a larger colonoscope. Care should be taken to minimize insufflation to avoid barotrauma to the proximal colon while attempting to pass a difficult turn or structure in the distal colon. In addition, difficult turns are often caused by intraabdominal adhesions. Therefore, changing the patient’s position can often make passing the turn easier. The patient position can be changed to supine, prone, or right lateral decubitus depending on the portion of the colon in which the difficulty is arising. Difficulty may be encountered when attempting to traverse the hepatic flexure. This may be due to accumulated loops, or simply due to excessive length of scope in the colon, minimizing efficiency of forward movement. The endoscopist should recall that in the most common position, left lateral decubitus, the scope is trying to advance, not only ahead of a significant length of scope but also against gravity, Thus taking advantage of repositioning the patient in the supine position can alleviate one of the factors contributing to the difficulty in navigating the turn. In some cases prone positioning may be employed so as to use the patient’s own weight to stabilize loops. It should be noted that if all of the above is attempted, the next step should be to abort the colonoscopy and obtain a CT colonography to evaluate the remainder of the colon rather than make further attempts to pass the scope and increase the possibility of perforation.

Diverticulosis presents a peculiar perforation risk either from pushing the scope through a diverticulum while mistaking the diverticulum lumen for the colonic lumen or mistaking an inverted diverticulum and taking an inadvertent full-thickness biopsy of colonic wall. Special care should be taken to be aware of the challenge of identifying diverticula, and a high level of suspicion should be applied to the lumen or polyp that does not have a typical appearance .

Bleeding is more commonly associated with therapeutic colonoscopy and is rare with diagnostic colonoscopy [8]. Bleeding occurs in 1–2% of polypectomies, and this rate increases for polyps that are larger and more difficult to remove [8–12]. The risk of bleeding is also higher in patients with known coagulopathies, history of thrombocytopenia , or patients taking anticoagulant or antiplatelet therapy .

Bleeding complications can be categorized relative to the time of presentation: immediate or delayed. Immediate bleeding can usually be recognized at the time of polypectomy. This occurs secondary to biopsy or snare without the use of cautery or the use of blended current for electrocoagulation. If identified during colonoscopy, bleeding can be treated immediately with epinephrine injection or endoscopic clipping. If recognized in the recovery room or the same day as the procedure, repeat colonoscopy with clipping can be undertaken. Figure 20.2 demonstrates a visible vessel associated with a diverticulum (a) and the vessel after clip placement (b).

Delayed bleeding is typically seen several days to a week after the colonoscopy, but has even presented up to 1 month after the colonoscopy. Delayed bleeding is typically associated with the use of endoscopic electrocoagulation. Approximately 1 week after the use of cautery with polypectomy, the eschar sloughs off and may result in bleeding, especially in those patients who had previously had their anticoagulation prior to the procedure and have since restarted their medication. An alternative mechanism proposed involves delayed thermal injury from the electrocautery with subsequent necrosis and erosion into a nearby vessel. Patients typically present with hematochezia or melena, but can also present with symptoms from the effects of anemia and hypotension. If the patient is hemodynamically stable and the bleeding appears to have stopped, they can be admitted to the inpatient unit for close monitoring of vital signs, signs of ongoing bleeding, and hemoglobin levels. If the patient is hemodynamically unstable, the patient should be resuscitated prior to any attempt to stop the bleeding. If the patient is hemodynamically stable with signs of ongoing bleeding, colonoscopy can be undertaken with clip placement or epinephrine injection if the site of bleeding can be identified. Unlike the performance of colonoscopy in a patient with bright red blood per rectum from an unknown source, the polypectomy sites should be known to the endoscopist, and special attention to identify the bleeding at biopsy sites can be taken. If significant clot has accumulated in the colon, large-volume irrigation may be necessary to identify the bleeding site [13]. Figure 20.3 displays a treatment algorithm for treatment of postpolypectomy bleeding.

Postpolypectomy syndrome (postpolypectomy anticoagulation syndrome ) is a constellation of symptoms that may be characterized by abdominal pain, fever, leukocytosis, and localized peritonitis. These symptoms can occur without associated bowel perforation or pneumoperitoneum and occur after polypectomy with electrocoagulation. Because of the overlap with many symptoms of bowel perforation, clinicians should be aware of this syndrome to avoid unnecessary emergent surgery.

The incidence in the literature varies from 0.3 to 50 per 10,000 colonoscopies. As with bleeding, the incidence of postpolypectomy syndrome is increased when larger, more complicated polyps are removed [11, 14–16]. In fact, signs of postpolypectomy syndrome have been reported in up to 40% of cases involving endoscopic submucosal dissection [17, 18].