can be obtained by the use of bipolar coagulation or heater probes. Perforation rates with these devices range from 0 to 2%, and are increased when treatment is repeated.38,39 Monopolar probes have higher rates of perforation and have largely been abandoned.
Endoscopic tools available to treat esophageal variceal bleeding include band ligation, variceal obliteration, and sclerotherapy. Endoscopic band ligation is as effective as sclerotherapy with fewer and less severe complications (perforation rates: < 0.7 vs. 2–5%; superficial ulceration rates: 5–15 vs. 70–90%, respectively) and a major impact on overall mortality. It has become the preferred technique for acute bleeding, and primary and secondary prophylaxis of variceal bleeding.40,41,42 Injection of cyanoacrylate is more effective than endoscopic band ligation for gastric variceal bleeding but is not without risks, such as embolization, which occurs in 2 to 5% of cases.43 Pulmonary embolism is usually limited and with marginal clinical consequences. Paradoxical embolism may occur (especially in unsedated patients who have transient opening of the foramen ovale) with lethal outcome.
Removal of Foreign Bodies
Adverse event rates encountered during the removal of foreign bodies can reach 8%.44 The most common complication is aspiration pneumonia, which can be prevented by endotracheal intubation, sometimes difficult in an emergency situation. Another major complication is mucosal tearing, which occurs during retrieval of sharp objects through the esophagus. Tearing can be prevented by using a protector hood at the distal extremity of the scope or by the use of an overtube. However, an overtube itself can induce mucosal tearing and perforation of the esophagus. Its use should be restricted to patients placed in the left lateral decubitus position in order to ensure neck overextension during overtube insertion.
10.3.3 Management of Upper Gastrointestinal Perforation
While perforation is a feared and well-known complication of upper GI endoscopy, its management has evolved and is no longer considered an absolute indication for surgery. Endoscopic closure of small perforations (< 2 cm) recognized during the procedure can be achieved using through-the-scope (TTS) clips. Larger over-the-scope closing devices may be useful in selected situations.45,46 SEMSs (partially or fully covered) have also been used to treat large perforations, especially those occurring after dilatation.24,26 An algorithm for the management of upper GI perforation is presented in
In the case of suspected delayed esophageal perforation (characterized by persistent or increasing pain, fever, respiratory distress, and hemodynamic instability), a water-soluble contrast radiographic study is the examination of choice. Alternatively, computed tomography (CT) scan of the neck and chest can be used. Endoscopic closure can be performed in concert with drainage of any fluid visualized collection, when possible.24
In the case of gastric or duodenal perforation, the same principles are applicable, but endoscopic closure mainly relies on the use of clips combined with gastric aspiration.45
10.3.4 Management of Upper GI Bleeding
Bleeding during therapeutic endoscopy is part of the procedure especially during polypectomy, EMR, or ESD. Immediate and late bleeding can be managed using coagulation forceps (preferred during EMR or ESD) or clips. Bleeding occurring after esophageal stenting, especially when occurring late after the initial procedure, should always be evaluated by proper imaging, given the potential risk of esophago-aortic fistulas.48
10.4 Small Bowel Endoscopy
Various endoscopic techniques can be used to explore the small intestine. These include push enteroscopy, single and double-balloon enteroscopy (SBE and DBE, respectively), spiral enteroscopy, and video capsule endoscopy. The most widely available published data concern DBE and video capsule endoscopy. The most common adverse events associated with DBE include perforation, bleeding, pancreatitis, and adverse events related to sedation. The rate of adverse events associated with DBE ranges from 0.4 to 0.8% for diagnostic procedures and 3 to 4% for therapeutic procedures.49,50 The rate of pancreatitis associated with the antegrade DBE is consistently reported to be around 0.3%. The mechanisms of pancreatitis remain poorly understood. Pancreatitis may be prevented by avoiding inflation of the balloon at the duodenal level.51 Management of perforation following enteroscopy usually requires prompt surgical intervention.
Fig. 10.1 Perforation during colonoscopy may occur after polypectomy (a, c) or may be due to direct trauma of the endoscope (b, d). When limited in size, most are amenable to immediate treatment with endoscopic clip placement.
The main complication of video capsule endoscopy is capsule retention (frequency 1–2%).52 Retention is more common in cases of stenosis, especially those associated with Crohn’s disease. The identification of a radiological abnormality of the small bowel is associated with a risk of capsule retention of 15.4%, usually requiring surgical or DBE exploration for retrieval.53
10.5 Colonoscopy
Colonoscopy is the gold standard for diagnosis of colorectal cancer and treatment of colorectal polyps. The rate of significant adverse events for diagnostic colonoscopy ranges from 0.02 to 0.07%.54 The bowel preparation itself, if performed with sodium phosphate, may be associated with hypovolemia, hyperphosphatemia, and eventually death. Age, preexisting renal failure, and the use of nonsteroidal anti-inflammatory drugs (NSAIDs) are risks factors for this complication.55
10.5.1 Perforation
The reported frequency of this most feared complication varies in the literature. In a multicenter, prospective survey of 9,223 colonoscopies performed in England, the perforation rate was 0.11% for diagnostic and 0.21% for therapeutic colonoscopy.54
Three different mechanisms exist by which colonic perforation might occur during endoscopy: pneumatic perforation of an already weakened colonic wall; mechanical perforation owing to excessive pressure by the scope against the colonic wall; and posttherapeutic colonoscopy perforation, which can occur when the colonic wall has been made fragile by polypectomy, EMR, ESD, and/or coagulation during therapeutic colonoscopy. Following the results of a report of 183 colonic perforations, the most predominant site of perforation was the sigmoid colon (72%), followed by the ascending and descending colon (8.6% each), the rectum (6.9%), and the transverse colon (3.4%).56 Risks factors for perforation during colonoscopy include the following: therapeutic colonoscopy (polypectomy, EMR, stricture dilation, and argon plasma coagulation use), age > 75 years, diverticular disease, previous intra-abdominal surgery, colonic obstruction, and female gender.57
Intraprocedural perforations occurring during EMR or ESD (the latter in approximately 30% of cases)58 are frequently recognized immediately, with the “target sign” on the resection specimen useful.
