Interventional endoscopy

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CHAPTER 7 Interventional endoscopy

7.1 Stricture dilation

Mouen Khashab, François Cessot, Sanjay Jagannath

Summary

Introduction 155
1. Clinical and endoscopic assessment 155
2. Equipment 157
3. Endoscopic techniques 157
4. Complications 161

Key Points

• Apply the ‘rule of 3’ as a guideline when using bougie dilation to dilate esophageal strictures.
• Do not perform pneumatic dilation in achalasia patients who are not fit for surgery because if perforation occurs, it may require surgical management. Alternative therapeutic options, such as Botox injection, may be better choices.
• Esophageal dilation in the setting of eosinophilic esophagitis (EE) carries a high risk for deep tears and esophageal perforation. Dysphagia due to EE is best treated with topical steroids.
• Use an upper endoscope for high-grade left-sided colonic strictures and a pediatric colonoscope for more proximal strictures.

Introduction

Strictures, both benign and malignant, occur in all regions of the gastrointestinal (GI) tract, but are most common in the esophagus. Dilation of benign strictures is considered definitive therapy, while dilation of malignant strictures is considered palliative therapy, primarily because the response to dilation is short-lived. Malignant strictures are dilated primarily to aid in the successful completion of other endoscopic procedures such as palliative stent placement or endoscopic ultrasonographic tumor staging.

An understanding of the various tools and techniques used to perform safe and effective GI stricture dilation is essential because: (1) strictures are commonly encountered in daily practice and (2) potential serious complications can occur when performing stricture dilation.

1 Clinical and endoscopic assessment

1.1 Esophageal strictures

• Esophagogastroduodenoscopy (EGD) should be the initial diagnostic test in patients who (1) present with dysphagia consistent with an esophageal obstruction; (2) are at least 40 years of age with new onset dysphagia, and (3) in any patient with dysphagia and alarm symptoms (e.g. odynophagia, weight loss, anemia, etc).
• Box 1 depicts the etiologies of mechanical esophageal obstruction.

Box 1 Causes of esophageal strictures

• Peptic injury.
• Schatzki’s ring.
• Esophageal webs.
• Esophageal cancer.
• Corrosive injury.
• Radiation therapy.
• Esophageal surgery.
• Eosinophilic esophagitis.
• Sclerotherapy.
• Photodynamic therapy (PDT).
• Endoscopic mucosal resection (EMR).
• Radiofrequency ablation (RFA).
• Cryotherapy.
• Sclerotherapy.
• Infectious esophagitis.
• Pill-induced esophagitis.

• Anticoagulants should be discontinued for the procedure, based on existing recommendations (see Ch. 1).
• The risk of bacteremia after esophageal bougienage is 12–22%, which is less than that associated with brushing of teeth. Antibiotic prophylaxis solely to prevent infectious endocarditis is not recommended prior to luminal stricture dilation.
• Patients should fast for at least 4 h prior to the procedure, and ideally 8 h for patients who have eaten food. In certain clinical scenarios, such as achalasia dilation, patients should fast for longer time periods (see below).
• Strictures are anatomically classified into simple or complex strictures. Complex strictures have at least one of the following features: asymmetry, diameter ≤12 mm, or inability to pass the endoscope. Complex strictures that are long or too tight to allow passage of an endoscope can be safely dilated under fluoroscopic guidance.
• The esophageal mucosa should be examined for endoscopic features of eosinophilic esophagitis (EE). Esophageal dilation in the setting of EE carries a high risk for deep tears and esophageal perforation. Dysphagia in the setting of EE responds well to topical steroid therapy, and dilation may not be necessary.
• For patients who complain of dysphagia, but do not have an endoscopically visible stricture, empiric esophageal dilation is discouraged. This technique has not been shown to be clinically effective. In addition, the patients may have undiagnosed EE, and dilation in this clinical scenario carries an extremely high risk of complication.

image Clinical Tips

• Patients with achalasia may need a prolonged fast prior to dilation because of a higher risk of aspiration due to esophageal stasis.
• Look for endoscopic features of eosinophilic esophagitis: ringed esophagus and mucosal furrows. If EE is suspected, a total of five biopsy specimens must be obtained from the proximal and distal esophagus.
• Do not perform empiric dilation for esophageal dysphagia when a stricture is not identified: it is clinically ineffective and has the potential risk of serious complications.
• Biopsy specimens of the stricture should be obtained to exclude malignancy when the clinical presentation (such as rapid progression of dysphagia or significant weight loss) or the endoscopic appearance (such as the presence of a mass) is suggestive.
• Biopsy specimens of a stricture to rule out occult malignancy should be obtained in patients with strictures that are refractory to dilation.

1.2 Gastric, pyloric, and small bowel strictures

• Non-esophageal upper GI (UGI) strictures occur most commonly at the pylorus and manifest as gastric outlet obstruction. Etiologies of gastric or pyloric strictures are illustrated in Box 2. Peptic ulcer disease (PUD) is the most common cause of gastric outlet obstruction.

Box 2 Causes of non-esophageal upper GI strictures

• Peptic ulcer disease.
• Corrosive injury.
• Crohn’s disease.
• Radiation therapy.
• Postoperative.

• Endoscopic dilation of UGI strictures due to Crohn’s disease often do not respond long term due to the high recurrence rate.
• The use of fluoroscopy is advocated for strictures that cannot be traversed with the scope.
• Roux-en-Y gastrojejunal bypass (RYGB) is one of the most common surgeries performed today for the treatment of morbid obesity. Gastrojejunal stomas are generally 10–12 mm in diameter. Anastomotic strictures are defined as stomas with diameter <10 mm and occur in 3–28% of these patients.

image Clinical Tips

• History of non-steroidal anti-inflammatory drugs (NSAIDs) intake needs to be elucidated in these patients and Helicobacter pylori infection needs to be ruled out.
• Prolonged gastric outlet obstruction may result in gastric atony. Response to endoscopic therapy is not immediate in these patients.
• Suspicious strictures must be biopsied to rule out malignancy.

1.3 Ileocolonic and colonic strictures

• Etiologies of ileocolonic and colonic strictures are depicted in Box 3. The most common site for these strictures is at surgical anastomoses.

Box 3 Causes of ileocolonic and colonic strictures

• Postoperative.
• Crohn’s disease.
• Radiation injury.
• NSAID colopathy.
• Diverticular disease.
• Ischemia.
• Malignancy.

• Dilation of colonic strictures should only be performed if the patient is symptomatic.
• NSAID colopathy most commonly manifest in the right colon and may lead to colonic strictures with a pathgnomonic ‘diaphragm type’ appearance.

2 Equipment

• Diagnostic upper endoscope
• Pediatric colonoscope (for proximal colonic strictures)
• Dilators (Table 1)
• Guidewires
• Fluoroscopy
• Achalasia Rigiflex balloon dilator.

Table 1 Esophageal dilators

image

3 Endoscopic techniques

3.1 General principles

3.1.1 Dilation using bougies

• Bougies exert both shearing and radial force and dilate progressively from the proximal to the distal end of the stricture (Fig. 1).
• The initial dilator size chosen should equal the estimated diameter of the stricture.
• Apply the ‘rule of 3’: Use no more than three dilators successively larger than the first dilator to meet moderate resistance when passed. This rule is a general guideline, and physicians should use their clinical discretion when dilating strictures.
• Savary dilation involves passage of spring-tipped guidewire via the working channel of the endoscope, followed by withdrawal of the endoscope while leaving the guidewire in place (Fig. 2).
• If the stricture is not traversable by the endoscope, then the guidewire is passed through the stricture under fluoroscopic guidance, with the tip of the endoscope placed just above the stricture. The endoscope is then withdrawn leaving the guidewire in place. One should not advance the guidewire if firm resistance is met.
• A conservative approach to dilation is recommended to reduce the risk of perforation. Patients are usually brought back in 1–2 weeks for repeat sessions to achieve sufficient dilation.
image

Figure 1 Radial and longitudinal forces. Bougies are associated with longitudinal dilation forces (A), while balloon dilation is associated with radial dilation forces (B).

image

Figure 2 Bougies.

image Clinical Tips

• Do not try to accomplish too much dilating in one setting.
• Apply the ‘rule of 3’ as a guideline when using bougie dilation. Use no more than three dilators successively larger than the first dilator to meet moderate resistance when passed.

3.1.2 Dilation using balloons

• Balloons exert radial force only and the force is applied simultaneously to the entire length of the stricture (Fig. 1).
• The ‘rule of 3’ does not apply to balloon dilators.
• There are multiple TTS balloons that are available in either single or multiple diameters. The balloons may be passed with or without wire guidance (Fig. 3).
• The balloon is advanced through the working channel of an endoscope and then through the stricture under direct endoscopic visualization (Figs 4, 5).
• The balloon should remain inflated for 30–60 s although the optimal duration is not known.
• Fluoroscopic and wire guidance may be used for tight strictures that are not traversable with the endoscope.
• Most widely used balloons are the controlled radial expansion (CRE) TTS balloons, which have three different inflation steps that achieve graded dilation.
image

Figure 3 Ballon dilation. Balloons can also be placed on a guidewire outside the endoscope (A). Through the scope (TTS) esophageal balloonscan be non-wire guided (B) or wire guided (C).

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Figure 4 Balloon dilation. Syringe gun, manometer and balloon (A).Through the scope (TTS) balloon (B), and following inflation (C). TTS balloon is inserted into the operating channel (D).

image

Figure 5 Dilation of an esophageal stricture with a balloon. (A) Peptic stricture. (B) The balloon is placed across the stricture – note the ‘waist’ (arrow). (C) Note the obliteration of the waist following successful dilation. (D) Endoscopic image of the stricture during balloon dilation. (E) Following dilation: note the presence of several mucosal tears (white arrows).

image Clinical Tips

• It is of the utmost importance to maintain balloon position through the stricture during balloon inflation. The proximal portion of the catheter remaining outside of the endoscope should be held firmly against the endoscope using the endoscopist’s left little finger in order to prevent the balloon from slipping out of the stricture as it is inflated. Failure to do so may cause the balloon to slip out of the stricture and only part of the stricture may be dilated. In general, a slow inflation of the balloon to anchor to its initial diameter will secure it in the stricture and minimize the risk of migration. In addition, use of the longer balloon will help to minimize slipping out of the stricture.
• You cannot apply the ‘rule of 3’ to balloon dilation.
• Inflate the balloon using water and with radiologic product of contrast rather than air, because liquid is less compressible than gas in tight strictures.

3.2 Esophageal strictures

• No difference in outcome has been observed between bougie and balloon dilation.
• Schatzki’s rings are best treated with passage of single large diameter bougie (16–20 mm) to achieve rupture of the ring. Although most patients experience symptom relief after dilation, dysphagia recurs in 90% of patients within 3 years. Repeat dilation is advised on a needed basis. There is some evidence that acid suppression may prevent recurrence of Schatzki’s rings.
• Webs occur in the upper and mid-esophagus and respond well to bougie dilation.

image Warning!

Do not mistake eosinophilic esophagitis for multiple esophageal webs. These are different pathologies. Eosinophilic esophagitis carries a high risk of perforation, especially if dilation is performed with a single large diameter bougie.

• Peptic strictures may be treated with bougienage (using the ‘rule of 3’) or balloon dilation. Patients should be placed on proton pump inhibitor (PPI) therapy and strictures will recur in as few as 30% of these patients.
• Corrosive strictures require more dilation sessions and are associated with a higher recurrence rate as compared to peptic strictures. The use of bougies seems most suitable for these strictures.
• Anastomotic strictures are common after esophagectomy, and are most commonly treated with balloon dilation.
• Radiation-induced strictures are best treated with bougie dilation.
• Injection of steroids into benign recurrent or refractory esophageal strictures may improve the outcome of dilation.

image Clinical Tips

Steroid injection technique

The procedure involves using 200 mg of triamcinolone (40 mg/mL). Using a standard sclerotherapy catheter, 1 mL aliquots are injected into the distal margin of the stricture in a four-quadrant fashion.

• Dilation of malignant strictures provides only temporary relief of dysphagia that lasts from a few days to 2 weeks and it may be performed using either bougie or balloon dilation. Dilation is usually performed to allow passage of echoendoscope to perform tumor staging, stent placement, or laser therapy.
• ASGE guidelines for the performance of esophageal dilation are summarized in Box 4.

Box 4 ASGE guidelines for the performance of esophageal dilation

• Fluoroscopy can be used when using non-wire guided dilators during dilation of complex esophageal strictures or in patients with a tortuous esophagus.
• Bougie and balloon dilators are equally effective in patients with esophageal strictures.
• The ‘rule of 3’ should be followed when dilation of esophageal strictures is performed with bougie dilators.
• Steroid injection into recurrent or refractory benign esophageal strictures may improve the outcome after esophageal dilation.
• Administration of PPIs is effective in preventing recurrence of esophageal strictures and the need for repeat esophageal dilation.

image Clinical Tips

• If you are not sure if the stricture is peptic or a Schatzki’s ring, treat it as a peptic stricture by using the ‘rule of 3’.
• Remember that you only need to dilate the stricture to 13–15 mm diameter to relieve dysphagia.
• PPI therapy improves outcome of peptic stricture dilation. This may also apply to Schatzki’s rings.

3.3 Achalasia

• A thorough EGD examination is performed first to clear the esophagus of luminal contents, exclude esophageal or proximal gastric cancer (causing secondary achalasia), determine the extent of esophageal tortuosity, and identify the presence and localization of a hiatal hernia for appropriate localization of the LES fluoroscopically.
• Pneumatic dilation is performed using Rigiflex balloon dilators with balloon diameters of 30 mm, 35 mm, or 40 mm.
• Dilation is generally performed over a guidewire under fluoroscopic guidance initially using a 30 mm balloon. Non-fluoroscopically guided dilation using endoscopic visualization alone is feasible and can be performed safely in expert hands.
• The balloon is first inflated to 3 pounds per square inch (PSI) to confirm appropriate localization of the balloon and looking for a waist in its center. The balloon is then inflated slowly up to a limit of 10 PSI. Complete obliteration of the waist should be noted fluoroscopically.
• A water-soluble contrast esophagram should be obtained after the patient has awakened to rule out procedural perforation.
• Fluoroscopy before and after dilatation should be performed to check for the presence of air in the mediastinum. If this is present it suggests that a perforation has occurred.
• If the initial treatment is unsuccessful, repeat dilation with a larger balloon may be performed at a later setting.
• Patients usually require 2–3 dilations over a 5-year period to remain in symptomatic remission.
• Gastroesophageal reflux disease develops in some patients after pneumatic dilation, but it responds readily to PPI therapy.
• ASGE guidelines for the performance of pneumatic dilation in achalasia are summarized in Box 5.

Box 5 ASGE guidelines for the performance of pneumatic dilation in achalasia

• Pneumatic dilation with large-diameter balloons is effective for the treatment of achalasia.
• Botulinum toxin therapy is the preferred endoscopic treatment for achalasia in poor operative and non-operative patients.

image Clinical Tips

• Do not exceed a balloon pressure of 10 PSI because of an increased chance of perforation above this limit.
• Do not perform pneumatic dilation in achalasia patients who are not fit for surgery because if perforation occurs, it may require surgical management. Alternative therapeutic options, such as Botox injection, may be better choices (see below).

3.4 Gastric/pyloric strictures

• Pyloric strictures are mostly treated with balloon dilation although successful treatment using Savary dilators has also been reported in the literature.
• A non-surgical approach for the treatment of these strictures is associated with high failure or recurrence rate. Repeat dilations every 1–2 weeks may be required to try to avoid surgery.
• Long fibrous Crohn’s strictures are best treated surgically.
• Pyloric strictures that are not traversable and those that are long and extend to the C loop of the duodenum are best dilated by passing the balloon over a guidewire under fluoroscopic guidance.
• Gastrojejunal anastomotic strictures in RYGB patients can be treated effectively by using either balloon or bougie dilators. Dilation to 15 mm only is recommended to avoid weight regain.

3.5 Small intestinal/colonic strictures

• Use an upper endoscope for high-grade left-sided strictures and a pediatric colonoscope for more proximal strictures. Enteroscopy (push or balloon) can be used to access and dilate strictures beyond the reach of an upper endoscope or colonoscope.
• These strictures are usually treated using balloon dilators. Bougie dilation may be suitable for distal colonic or rectal strictures.
• There is data to suggest that dilating colonic strictures to a diameter larger than 51 French is associated with better outcome. Large diameter balloons (up to 25 mm in size) are available for the treatment of colonic anastomotic strictures.

image Clinical Tip

Most Crohn’s strictures occur at previous surgical anastomoses, although de novo stricture may occur and are also amenable to balloon dilation. However, only symptomatic strictures need to be treated!

• Once the stricture is dilated allowing passage of the endoscope, the remaining proximal colon should be examined to evaluate for more proximal strictures. If there is any concern for malignancy, the stricture should be biopsied.
• Colocolonic anastomotic strictures can be dilated to 15–18 mm in one treatment setting. In the setting of ileal or neo-terminal strictures, the initial dilation is taken to 10–12 mm. If there is no symptomatic response, a second dilation to 15 mm is undertaken during a later session. Strictures stemming from Crohn’s disease, diverticulitis, ischemia, or radiation therapy are rarely taken past 10–12 mm during the first treatment session.

image Clinical Tip

If the colonic stricture cannot be traversed with an endoscope, fluoroscopy is used. Placement of the balloon over a guidewire is helpful for high-grade strictures and those associated with an end-to-side anastomosis. If difficulty is encountered in passing the guidewire across the stricture, a more flexible hydrophilic 0.021 or 0.035 mm ERCP guidewire may be helpful. In the case of near total colonic obstruction, a standard ERCP catheter may be placed over the guidewire and standard contrast will be used to determine the length and geometry of the stricture.

4 Complications

• The most serious complication of esophageal dilation is perforation which occurs in 0.1–0.4% of procedures (Box 6).

Box 6 Esophageal perforation

• Occurs in 0.1–0.4% of patients undergoing dilation.
• Risk is higher in complex strictures and radiation induced strictures.
• Perforation should be suspected with symptoms and signs of fever, tachycardia, persistent pain, dyspnea or subcutaneous crepitus.
• Confirm diagnosis with water-soluble contrast esophagram or contrast chest CT.
• Many patients may be managed conservatively with nasogastric tube placement and intravenous antibiotics.
• Some perforations are amenable to treatment with placement of an esophageal stent.

• The published rate of perforation following dilation of malignant esophageal strictures is 10%. However, the actual rate in the hands of experienced endoscopists may be as low as 1–2%.
• The risk of perforation with balloon dilation in achalasia is in the range of 3–4% with a mortality of <1%.
• Perforation rate of 4–7% is reported in small series of balloon dilation of pyloric stenosis.
• Most series describing colonic stricture dilation depicted a complication rate of about 5%.

Further Reading

Borotto E, Gaudric M, Danel B, et al. Risk factors of oesophageal perforation during pneumatic dilatation for achalasia. Gut. 1996;39:9-12.

Hernandez LV, Jacobson JW, Harris MS. Comparison among the perforation rates of Maloney, balloon, and savary dilation of esophageal strictures. Gastrointest Endosc. 2000;51:460-462.

Kochhar R, Makharia GK. Usefulness of intralesional triamcinolone in treatment of benign esophageal strictures. Gastrointest Endosc. 2002;56:829-834.

Kuwada SK, Alexander GL. Long-term outcome of endoscopic dilation of nonmalignant pyloric stenosis. Gastrointest Endosc. 1995;41:15-17.

Lemberg B, Vargo JJ. Balloon dilation of colonic strictures. Am J Gastroenterol. 2007;102:2123-2125.

Pereira-Lima JC, Ramires RP, Zamin IJr, et al. Endoscopic dilation of benign esophageal strictures: report on 1043 procedures. Am J Gastroenterol. 1999;94:1497-1501.

Sgouros SN, Bergele C, Mantides A. Eosinophilic esophagitis in adults: what is the clinical significance? Endoscopy. 2006;38:515-520.

7.2 Emergency endoscopy in benign gastrointestinal obstruction

Mouen Khashab, Anne Le Sidaner, Sanjay Jagannath

Summary

Introduction 162
1. Volvulus 162
2. Acute colonic pseudo-obstruction 165

Key Points

• Patients with acute gastric volvulus may present with Borchardt’s triad of pain, unproductive retching, and the inability to pass a nasogastric tube.
• Acute endoscopic reduction of gastric volvulus can be performed using the alpha-loop maneuver.
• An initial attempt at endoscopic detorsion can be followed in stable patients with sigmoid volvulus. Placement of a decompression tube decreases early recurrence.
• Majority of patients with acute colonic pseudo-obstruction (ACPO) respond to neostigmine therapy. Placement of a decompression tube decreases recurrence.
• Patients with ACPO who fail medical and endoscopic therapy should undergo surgical therapy.

Information about the emergency management of gastroduodenal or colonic obstruction due to stricture or malignancy can be found in Chapter 7.3.

Introduction

Gastroduodenal and colonic obstructions are common clinical entities treated by gastroenterologists and surgeons. It is critical to recognize those disease states that are better treated endoscopically and thus avoid the morbidity and mortality of a more invasive approach, e.g. surgery. Gastrointestinal obstruction may result from either mechanical cause or failure of intestinal motility in the absence of obstructing lesions (ileus, pseudo-obstruction). The obstruction should be classified as simple or strangulated, depending on whether there is absence or presence of intestinal ischemia, respectively. Strangulated obstructions have worse outcomes and treatment is generally surgical. Interventional gastroenterologists play a crucial role in the management of simple obstructions.

1 Volvulus

1.1 Gastric volvulus

Gastric volvulus is a rare, potentially life-threatening entity that occurs when the stomach twists upon itself (Fig. 1). By definition, gastric volvulus is rotation of the entire or part of the stomach more than 180°. It is supra-diaphragmatic and associated with a paraesophageal or a mixed diaphragmatic hernia in two-thirds of the cases, and is subdiaphragmatic in the remaining one third. The volvulus is organoaxial in 60% of cases where the axis passes through the gastroesophageal and gastropyloric junctions, and mesenteroaxial in 40% of cases where the axis bisects the lesser and greater curvatures.

image

Figure 1 Barium contrast study showing organoaxial gastric volvulus (arrow).

Gastric volvulus can present as: (1) transient event with mild short-lived upper abdominal symptoms; (2) chronic volvulus with mild and non-specific symptoms such as dysphagia, hiccups, early satiety, bloating, heartburn, and upper abdominal discomfort, with symptoms being worse after meals; or (3) acute gastric volvulus which presents with sudden onset of severe pain in the upper abdomen or lower chest and unproductive retching. Some patients present with Borchardt’s triad of pain, unproductive retching, and the inability to pass a nasogastric tube.

Although strangulation is more common in organoaxial volvulus, it only occurs in 5–28% of these cases due to the rich blood supply of the stomach. Mesenteroaxial volvulus usually causes incomplete obstruction that may be intermittent in nature.

If gastric volvulus is associated with a diaphragmatic hernia, physical examination may reveal evidence of the stomach in the left chest. Chest X-ray will reveal a gas-filled viscus in the chest. The diagnosis is usually confirmed with a barium upper gastrointestinal study. Upper endoscopy will show twisting of gastric folds at the point of torsion.

image Warning!

• EGD should be avoided if there is suspicion of gastric ischemia or perforation, such as in patients with rebound abdominal tenderness.
• If EGD is performed, the endoscope should be advanced forward gently and air insufflation should be kept to a minimum.

Acute gastric volvulus carries a high mortality risk if not recognized early. Early diagnosis and surgical correction remain the mainstays of therapy. Nonetheless, gastroenterologists still play a crucial role in the diagnosis and management of acute and chronic gastric volvulus.

• Chronic gastric volvulus presents with mild and non-specific symptoms. The endoscopist performing the EGD can recognize the presence of twisted gastric folds, which establishes the diagnosis.
• An endoscopist may diagnose acute gastric volvulus when performing upper endoscopy on a patient with more severe and acute symptoms. Stomach decompression with a nasogastric tube may be attempted. Reduction of an acute volvulus may be achieved with this intervention alone.

image Clinical Tip

Placement of a nasogastric tube in acute gastric volvulus may be unsuccessful in patients with organoaxial rotation due to complete obstruction at the cardia.

• The gastric mucosa should be inspected carefully for signs of ischemia and necrosis. The examination should be aborted if these signs are present because such patients are at higher risk of perforation with air insufflation.
• If signs of gastric infarction are not present, acute endoscopic reduction of the volvulus may be considered using the alpha-loop maneuver, which should be performed under fluoroscopic guidance.

image Clinical Tips

The alpha-loop maneuver (Fig. 2)

• The endoscope is slowly advanced through the narrow lumen formed by the twisted gastric folds of the fundus or body into the antrum. Once the antrum is entered, a J-turn maneuver is performed to confirm the passage of the endoscope through the gastric volvulus.
• The endoscope is then withdrawn back into the fundus. The endoscope is retroflexed and advanced with gentle pressure in the proximal stomach to form an alpha-loop. The tip of the endoscope is passed anterior to the retroflexed portion and re-advanced through the narrowed lumen into the antrum.
• The endoscope is then torqued in a clockwise manner to allow untwisting of the alpha-loop and reduction of the gastric volvulus.
image

Figure 2 Alpha-loop maneuver. (A) An Olympus magnetic imager showing an alpha loop and (B,C) the reduction of the volvulus, with straightening of the colonoscope.

• In surgically fit patients, semi-elective laparoscopic gastropexy should follow the reduction of gastric torsion after the patient is stabilized. Associated diaphragmatic hernias should also be repaired.
• In surgically unfit patients, simple endoscopic gastropexy may be performed by placement of one or two percutaneous gastrostomy (PEG) tubes.
• A management algorithm for patients with gastric volvulus is illustrated in Figure 3.
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Figure 3 Management algorithm for patients with acute gastric volvulus.

1.2 Colonic volvulus

Colonic volvulus is the third most frequent cause of large bowel obstruction after neoplasms and diverticulitis. Whereas colonic neoplasms and diverticulitis usually result in an open-loop obstruction where the lumen is occluded at a single point along the bowel segment, colonic volvulus occurs when a colonic segment becomes twisted on its mesenteric axis and occludes both ends of the bowel segment resulting in a closed-loop obstruction (Fig. 4). The mesentery gets trapped and the blood supply to the bowel segment becomes strangulated, potentially leading to gut ischemia, necrosis and perforation. Delay in diagnosis and decompression compromises viability of the bowel and is a major cause of mortality.

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Figure 4 (A) Plain AXR showing grossly distended loop of sigmoid colon. (B) Contrast radiology shows typical ‘bird’s beak’ occlusion at site of volvulus (arrow).

The sigmoid colon (Fig. 4) and cecum (Fig. 5) are the most frequent sites of colonic volvulus, accounting for 75% and 22% of all cases, respectively. Patients with acute colonic volvulus present most commonly with acute abdominal distension and may have other non-specific symptoms of abdominal pain, nausea, vomiting, and constipation. The diagnosis of colonic volvulus can be made with plain abdominal films (supine and upright) or water-soluble contrast enemas in 85% of the cases.

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Figure 5 Cecal volvulus. (A) Contrast enema study showing a cecal volvulus. (B) Reduction of the cecal volvulus with rectal tube inserted.

image Clinical Tips

• The use of barium as the contrast medium during contrast enema studies in patients with suspected colonic volvulus is discouraged because of risk of severe peritonitis in case of bowel perforation.
• A contrast-enema study may occasionally cause volvulus detorsion.

Acute colonic volvulus should be managed on an emergent basis. Patients with colonic necrosis/perforation should be managed surgically. A more conservative approach with an initial attempt at endoscopic detorsion and decompression can be followed in more stable patients (Fig. 6). The benefits of such a strategy are:

• Avoid emergency surgery on an un-prepped colon with risk of field contamination
• Avoid colostomy and its associated morbidity and mortality
• Improve quality of life by avoiding colostomy
• Allow a one stage semi-elective surgery with the possibility of a laparoscopic approach
• Assess the viability of colonic mucosa.
image

Figure 6 Endoscopic view of a sigmoid volvulus. (A) Before reduction. (B) Following endoscopic reduction.

image Clinical Tips

Endoscopic treatment of colonic volvulus

• Consult with your surgical colleagues before any attempt at endoscopic management of colonic volvulus.
• Avoid excessive air insufflation to minimize risk of perforation.
• Consider using carbon dioxide, if available, for colonic insufflation.
• Examination should be aborted if there is any evidence of colonic gangrene (e.g. the presence of bloody effluent in the colonic lumen is an indication of bowel gangrene); detorsion should be avoided in these cases as it can precipitate an irreversible septic shock.
• The volvulus should be traversed slowly with a flexible endoscope in the usual manner. A gush of stool is expected after successful detorsion.
• Place a decompression tube over a guidewire to decompress the distended colon and to decrease the early recurrence risk. Early recurrence rate is unacceptably high without tube placement. The tube should be placed on low intermittent suction and should be flushed with 20–30 mL of water or normal saline solution every 6 hours to maintain patency.
• Perform supine and upright abdominal radiography to confirm successful detorsion and to exclude pneumoperitoneum.
• Endoscopic treatment of colonic volvulus is only a temporizing measure.

image Warning!

Endoscopic management of cecal volvulus is less well defined than sigmoid volvulus because of a lower success rate (<33%) and a heightened cecal perforation rate because of the thinned-wall cecum.

Colonic segmental resection and primary anastomosis is considered the treatment modality of choice of colonic volvulus after successful endoscopic detorsion. Non-resectional techniques such as colonopexy and colonostomy carry a substantial risk of recurrence, but may be considered in high-risk patients.

2 Acute colonic pseudo-obstruction

Acute colonic pseudo-obstruction, also known as Ogilvie’s syndrome, is a disorder characterized by massive colonic dilation in the absence of colon obstruction. This definition excludes toxic colitis, which occurs in the setting of severe colitis secondary to inflammatory bowel disease or infection. It occurs most often in the setting of surgery and severe medical illnesses, and thus is a disorder of institutionalized patients. Acute colonic pseudo-obstruction is believed to result from autonomic imbalance with suppressed large bowel parasympathetic tone. This results in decreased colonic motility, accumulation of gas and fluid in the colon, increased intraluminal pressure, colonic distension and rising wall tension. Wall tension is highest in the cecum where the colonic diameter is the largest. This may result in the impediment of cecal capillary circulation and lead to ischemia, gangrene, and subsequent perforation. Plain abdominal radiographs show diffuse dilatation of the colon. A cutoff in the colonic gas is often seen at the hepatic flexure, splenic flexure, or sigmoid region with minimal air distal to the cutoff (collapsed left colon). Unlike toxic colitis, preserved haustral markings, smooth inner colonic contour, and thin colonic wall are present. In contrast to mechanical obstruction, air fluid levels are absent and distension is gaseous (Figs 7, 8). Water-soluble contrast enema is usually needed to rule out a true mechanical obstruction.

image

Figure 7 Acute colonic pseudo-obstruction. (A) A large dilated loop of bowel (white arrows). (B) A colonic decompression tube (white arrow) has been inserted as far as the splenic flexure.

image

Figure 8 Acute colonic pseudo-obstruction. (A) A plain abdominal film with evidence of large bowel dilation due to pseudo-obstruction. (B) A rectal decompression tube. (C) Insertion of the tube parallel to the colonoscope.

image Clinical Tips

• Radiographic contrast enemas are frequently needed in patients with acute colonic pseudo-obstruction to rule out mechanical obstruction.
• Avoid using barium as the contrast medium because of peritonitis risk if perforation occurs.
• The use of water-soluble contrast enema has a therapeutic effect in some patients by stimulating colonic motility, which sometimes speeds recovery.
• There is a small risk of colonic perforation with the use of enemas in patients with acute colonic pseudo-obstruction.
• Computed tomography scan may be needed in some patients to rule out a true mechanical obstruction.
• Clostridium difficile infection should be excluded with appropriate stool testing.

Therapy of acute colonic pseudo-obstruction can be divided into conservative treatment and active interventions. Conservative measures should be tried for 24–48 h, after which the condition usually resolves in most patients (at least in 75% of cases). Active interventions should be implemented if the disease progresses or does not respond to conservative measures.

Box 1 Treatment of acute colonic pseudo-obstruction: conservative measures

• Patients should be kept nothing by mouth.
• Nasogastric decompression should be initiated.
• Test for and correct any electrolyte imbalance (in particular potassium, magnesium, calcium, and phosphorus).
• Test for and treat thyroid dysfunction.
• Discontinue or minimize offending drugs, such as narcotics and anticholinergics, if possible.
• Mobilize patients out of bed if feasible.
• Manage concurrent illnesses.
• Obtain abdominal radiographs once every 12–24 h to follow cecal diameter.
• Serial abdominal examinations should be performed to assess for tenderness, worsening abdominal distension and signs of peritonitis.
• Water-soluble contrast enemas may be tried to liquefy the stool and stimulate colon motility.

image Warning!

• Conservative treatment alone should only be implemented when pain and abdominal distension are not extreme, and cecal diameter is <12 cm.
• Conservative treatment alone should be tried for a maximum of 48 hours in patients with tolerable symptoms because perforation risk increases significantly after 4–5 days.

Active interventions, including treatment with neostigmine and/or colonoscopic decompression, should be considered in patients who do not respond to a maximum of 48 h of conservative therapy, those with extreme abdominal pain, and those with cecal diameter >12 cm.

Neostigmine, an anticholinesterase parasympathomimetic agent, is usually the first medical agent tried in patients who do not have any contraindications to its use.

Box 2 Facts about neostigmine

• Three placebo-controlled double-bind randomized trials have documented the effectiveness of neostigmine.
• The majority of patients (80–90%) will respond to neostigmine with prompt evacuation of flatus and/or stool and a reduction in abdominal distension.
• It is given as a 2 mg intravenous dose. The dose may be repeated every 3 (or more) hours in case of recurrence.
• It has a low side-effect profile but potential serious side-effects, such as bronchospasm, bradycardia, hypotension, and seizures may occur. Side-effects are usually short lasting because of the short half-life of neostigmine.
• Neostigmine should only be given under close cardiac monitoring (continuous EKG monitoring and intermittent blood pressure measurements for 30 min after the dose is given). Atropine should be immediately available and should be given only for severe, prolonged, or symptomatic bradycardia.
• Other side-effects include salivation, nausea, vomiting, abdominal pain, restlessness, tremor, miosis, and sweating.
• The elimination half-life is prolonged in patients with renal insufficiency.
• Absolute contraindications to the use of neostigmine include the following: known hypersensitivity and mechanical urinary or intestinal obstruction. Relative contraindications include recent myocardial infarction, acidosis, asthma, bradycardia, peptic ulcer disease, and therapy with beta-blockers.

Colonoscopic decompression with placement of decompression tube should be performed in patients who fail neostigmine treatment.

Box 3 Facts about colonoscopic decompression in patients with acute colonic pseudo-obstruction

• Colonoscopic examination aids in ruling out mechanical obstruction and signs of colonic ischemia or necrosis.
• Decompression colonoscopy reduces colonic distension and prevents ischemia and perforation.
• Air insufflation should be kept to a minimum and the use of carbon dioxide, if available, for insufflation is advisable.
• Initial colonoscopic decompression is successful in about 70% of patients. In up to 40% of cases, the distension recurs requiring repeat colonoscopy.
• After repeat colonoscopy, the overall clinical success rate increases to 73–85%.
• Placement of a decompression tube in the right colon (proximal to the splenic flexure) increases the success rate to >90%.
• Decompression colonoscopy, although technically demanding, can be preformed safely with a reported mortality rate of 1% and a morbidity rate of 3% (mainly perforation risk).
• It is debatable if colonoscopy should be aborted if signs of colonic ischemia are present.
• Placement of a decompression tube has been shown to decrease recurrence rate.
• Colon preps/enemas are not needed because the stool remaining in the colon is usually liquefied and the colonic lumen is distended.
• Each colonic segment should be decompressed as soon as it is entered with the colonoscope.
• Cecal intubation is desired (if possible) for cecal examination and complete decompression.
• A guidewire is placed through the working channel of the colonoscope and advanced to the cecum (or the most proximal point reached by the colonoscope). The endoscope is then withdrawn and the decompression tube is placed over the wire.
• Fluoroscopy is needed for optimal tube placement to avoid the common problems of coiling of the tube and distal guidewire migration (which usually results in distal placement of the tube in the left colon).
• The tube should be taped securely to the buttocks, placed on low intermittent suction, and flushed with water or saline every 6 hours to prevent clogging.
• Daily abdominal radiographs should be obtained to follow colonic diameter and exclude pneumoperitoneum.

Patients who fail medical and endoscopic treatment and those with signs of colonic perforation/necrosis should be treated surgically with cecostomy or colectomy. Figure 9 illustrates an algorithm suggested by the ASGE for treating patients with ACPO.

image

Figure 9 ASGE algorithm for managing patients with ACPO.

Further Reading

Eisen GM, Baron TH, Dominitz JA, et al. Acute colonic pseudo-obstruction. Gastrointest Endosc. 2002;56:789-792.

Godshall D, Mossallam U, Rosenbaum R. Gastric volvulus: case report and review of the literature. J Emerg Med. 1999;17:837-840.

Loftus CG, Harewood GC, Baron TH. Assessment of predictors of response to neostigmine for acute colonic pseudo-obstruction. Am J Gastroenterol. 2002;97:3118-3122.

Madiba TE, Thomson SR. The management of cecal volvulus. Dis Colon Rectum. 2002;45:264-267.

Ponec RJ, Saunders MD, Kimmey MB. Neostigmine for the treatment of acute colonic pseudo-obstruction. N Engl J Med. 1999;341:137-141.

Renzulli P, Maurer CA, Netzer P, Buchler MW. Preoperative colonoscopic derotation is beneficial in acute colonic volvulus. Dig Surg. 2002;19:223-229.

Tejler G, Jiborn H. Volvulus of the cecum. Report of 26 cases and review of the literature. Dis Colon Rectum. 1988;31:445-449.

Tsang TK, Walker R, Yu DJ. Endoscopic reduction of gastric volvulus: the alpha-loop maneuver. Gastrointest Endosc. 1995;42:244-248.

7.3 Esophageal, duodenal and colorectal stenting

Mouen Khashab, Jean-Christophe Létard, Jean Marc Canard, Sanjay Jagannath

Summary

Introduction 168
1. General principles 168
2. Esophageal stenting 169
3. Duodenal stenting 173
4. Colonic stenting 175

Key Points

• Covered self-expandable metal stents (SEMS) resist tumor ingrowth, may be removable, and have a higher incidence of migration. Uncovered SEMS are non-removable, migrate less often, but tumor ingrowth occurs frequently.
• The various esophageal SEMS are equivalent in technical success, efficacy, and complication rates when used for malignant strictures.
• Patients with malignant gastric outlet obstruction and short life expectancy are best treated with endoscopic stenting.
• Main indications for colonic stenting are bridge to surgery in patients with colorectal cancer who present with colonic obstruction and palliation of inoperable malignant colorectal obstruction.

Introduction

Advances in interventional endoscopy over the last two decades have made an immense impact on clinical care. One such advance is the endoscopic placement of stents for the treatment and palliation of benign and malignant strictures involving the esophagus, duodenum, and colorectal regions of the gastrointestinal tract.

Esophageal cancer is one of the most lethal malignancies in the Western world. The incidence of esophageal cancer is rising at a faster rate as compared to any other GI cancer, and fewer than 50% of cases are curable and the 5-year survival rate is only 5–10%. For these reasons, palliative treatment of esophageal cancer remains an essential part of its management. Palliative esophageal surgery is associated with unacceptably high morbidity and mortality; it has largely been replaced by chemoradiation, brachytherapy, and/or endoscopic therapy. Among the available endoscopic techniques, endoluminal stenting is the most commonly employed because of its efficacy and wide availability.

Tumors involving the gastric outlet or the duodenum cause symptoms and signs of gastric outlet obstruction. Neoplasms that most commonly result in gastric outlet obstruction include pancreatic cancer, gastric cancer, carcinoid tumor, and metastases from other primary malignancies. Multiple studies have shown that palliative stent placement for unresectable tumors, as compared with palliative surgery, is more efficacious, cost-effective, and is associated with less morbidity and mortality.

Colorectal cancer, the third leading cause of new cancer diagnoses in the USA, often presents with partial or complete colon obstruction. Colorectal stenting has been used effectively for both palliation of malignant obstruction and as a bridge to curative surgery.

This aim of this chapter is to describe the general principles of GI luminal stenting and to focus on the use of endoscopically placed stents to treat benign and malignant obstruction of the esophagus, duodenum, and colon.

1 General principles

• Two broad categories of stents exist currently: self-expandable metal stents (SEMS), and self-expandable plastic stents (SEPS). In the past, semi-rigid plastic stents were used, but were associated with a higher complication rate, longer hospital stay, and worse clinical outcome when compared to SEMS and SEPS. Semi-rigid plastic stents are no longer used.
• Several manufacturers retail SEMS designed specifically for esophageal, duodenal, biliary, or colonic placement. These products differ in their physical properties and characteristics (length, diameter, flared endings, shortening during expansion, rigidity, material, radial expansive force, removability, and delivery systems).
• Covered and uncovered SEMS are available. Covered SEMS are designed to resist tumor ingrowth, while uncovered SEMS embed into the stricture and surrounding tissue. Fully covered SEMS (Fig. 1) may be removable, but have a higher incidence of migration. Uncovered SEMS are non-removable, migrate less often, but tumor ingrowth occurs frequently.
• Covered stents offer better long-term palliation for malignant disease than uncovered stents.
• One self-expandable plastic stent (Polyflex, Boston Scientific, Natick, MA) is available for esophageal use. This stent does not embed into the tissue and is approved by the US Food and Drug Administration (FDA) for benign disease and removability.
• All self-expandable stents may be placed with high rates of technical success with fluoroscopic guidance.
image

Figure 1 Fully covered SEMS. (A) Patient with multiple esophageal strictures, which were resistant to repeat dilation. (B) Fully covered esophageal stent inserted across the stricture. (C) Fluoroscopic image.

2 Esophageal stenting

2.1 General concepts

• Of patients with esophageal cancer, 50–60% present with surgically unresectable disease
• Dysphagia is the most distressing symptom
• Dilation only transiently improves dysphagia and carries a significant risk of perforation
• Dilation is primarily used as an adjunct treatment for stenting
• Stenting provides rapid relief of dysphagia
• All esophageal SEMS are covered
• The three most commonly studied SEMS are: Ultraflex, Wallstent, and Z-stent. Other stents exist
• The Polyflex stent is FDA-approved for the palliation of malignant diseases and for the treatment of benign diseases of the esophagus
• Currently available esophageal stents are not placed through the scope.

2.2 FDA-approved expandable esophageal stents (Table 1)

2.2.1 Ultraflex stent

• Ultraflex stent is partially coated (with a polyurethane membrane lining the middle of the stent while the proximal and distal 1.5 cm is uncovered).
• It has an easy-to-use delivery system which is 5.3 mm in diameter and can be deployed from the proximal to the distal end or vice-versa.
• The flared proximal end reduces the risk of food pocket formation between the stent and the wall and anchors the stent to the esophageal wall.
• The stent can theoretically be repositioned, if necessary, by means of a wire at its upper end.
• It is slow to expand (encouraging the patient to start eating again cautiously and gradually).
• Expansion is occasionally incomplete, requiring balloon dilation, which is not always effective. Perforation is rare.
• The Ultraflex stent has no bare metal edges and is less traumatic to the mucosa compared to the Wallstent.

Table 1 FDA-approved expandable esophageal stents

image

image Clinical Tips

Among all SEMS, the Ultraflex stent produces the least radial expansive force which, in theory, may be clinically relevant:

• Decreased risk of fistula formation
• Decreased risk of perforation
• Diminished efficacy (less relief from dysphagia).

2.2.2 Wallstent II

• This stent is partially coated with bare proximal and distal ends (2 cm on each end).
• It is easy to place and can be repositioned during the procedure. The stent can be recaptured as long as <50% of the stent has been deployed.
• The stent may foreshorten after deployment.
• The stent exerts a high radial force which may translate into better dysphagia relief, but increased post-procedural pain.
• It appears ideal for patients with advanced lesions.

2.2.3 Z-stent

• This stent is available as fully coated or partially coated with exposed flanges.
• The delivery system is rigid, and stent assembly is more complicated than other commercially available SEMS.
• A Z-stent with a ‘Dua’ antireflux valve is available for lesions that extend across the gastroesophageal junction (GEJ). The antireflux valve is an 8 cm extension of the polyurethane coating beyond the distal stent border. This polyurethane ‘windsock’ creates a one-way valve that shuts, with a rise in intragastric pressure, by collapsing on itself. With further increase in intragastric pressure, the valve can invert to allow vomiting or belching and returns, following a sip of water, to the intragastric position.

2.2.4 Alimaxx-E stent

• This is a relatively new stent and data are limited.
• The delivery system (7.4 mm in diameter) is easy to use.
• It is the only SEMS that is completely covered with a biocompatible membrane.
• The Alimaxx-E stent is the only SEMS in which removability is included in the guidelines for use (not FDA-approved yet).
• To remove the stent, grasp with suture, which is located at the proximal end of the stent, with a rat-tooth forceps. Then, apply firm, continuous traction by pulling on the endoscope in order to ‘peel’ the stent off the esophageal wall, and thus facilitate relatively atraumatic repositioning or removal.

2.2.5 Polyflex stent

• This is the only available SEPS (Fig. 2).
• The delivery system (diameter of 13 mm) is cumbersome. As such, Polyflex deployment frequently requires predeployment stricture dilation to 12–14 mm.
• It is the only stent approved for treatment of benign diseases of the esophagus and for removability (up to 9 months after placement).
image

Figure 2 Polyflex. This is the same patient as in Figure 1, with multiple esophageal strictures (A). The strictures were dilated (B) and a Polyflex stent inserted (C). However, this migrated into the stomach (D) necessitating removal and insertion of an fully covered removable SEMS.

2.3 Technique of stent placement

• The Ultraflex, Alimaxx-E, and Polyflex stents may be placed endoscopically without fluoroscopic guidance; however, fluoroscopic guidance is commonly used.

image Clinical Tips

• If a stricture is not traversable with a standard endoscope, a pediatric endoscope (6 mm diameter) may be used, if available.
• If the stricture is not traversable with the endoscope, stent placement must be performed under fluoroscopic guidance.
• The stricture needs to be dilated to allow passage of the delivery system (usually to a diameter of 9–10 mm and not exceeding 12–14 mm).
• If an endoscope cannot be passed beyond the stricture, the length and geometry of the stricture can be defined using a balloon and water insoluble contrast.

• The proximal and distal borders of the tumor are marked by endoscopic clips, injection of contrast material using sclerotherapy needle, or placement of external radio-opaque markers (Fig. 3).

image image

Figure 3 Insertion of esophageal stent. (A) Placement of radio-opaque marker and guide wire. (B) Measure distance of proximal and distal tumor margins from the teeth. (C) Delivery system through the stenosis. (D) Distal stent deployment. (E) The system is withdrawn. (F) Stent deployed.

image Clinical Tip

It is best to have the patient in supine position when external markers are placed, for optimal fluoroscopic visualization. Keep patient in same position during stent deployment.

• A stiff guidewire is positioned in the stomach through the stenosis.
• The scope is withdrawn.
• The delivery system with the stent is passed to the stomach over a stiff guidewire. The system is then withdrawn and the stent deployed with the assistance of fluoroscopy, so that the markings on the stent indicate that placement will be with at least a 2 cm margin proximal and distal to the marked tumor margins.
• Repeat endoscopic examination may be done to confirm the proximal end of the stent is above the proximal tumor margin.

image Clinical Tips

• Avoid traversing the stent after deploying it because of migration risk, as the stent has not fully expanded. Full stent expansion takes about 48 h.
• It is crucial to choose the proper stent length that will bridge the entire tumor. This may be accomplished by measuring the tumor length endoscopically or fluoroscopically.
• Remember that the chosen stent should be 2–4 cm longer than the stricture to allow for a 1–2 cm margin above and below the stricture proximal and distal margins. This allows for the covered portion of the stent to cover the stricture, thus reducing tumor ingrowth.

• More than one stent may be needed to cover long strictures. The second stent is placed in the same manner and positioned such that the two stents overlap for a distance of about 1–2 cm.

image Clinical Tip

Do not leave an excessive length of stent in the stomach because of the risk of gastric ulceration and bleeding when the stent rubs against the opposite gastric wall.

• If deployment is suboptimal based on fluoroscopic appearance, the stent may be dilated using a TTS balloon.
• Prescribe pain medications and proton pump inhibitor therapy before patient is discharged. Patients should also be advised on specific nutritional guidelines (Box 1).

Box 1 Nutritional guidelines following esophageal stent placement

• Have liquids for the first 24 h as the stent has not fully expanded.
• Chew all food properly and avoid dense and fibrous foods.
• Eat 5–6 small meals per day if needed.
• Eat slowly and take small bites.
• Sit upright while eating.
• Drink fluids in between meals if one feels ‘full’ with meals.
• Remain in an upright position at least 30–60 min after eating.
• If food ever feels ‘stuck’ in your throat, take sips of Coca-Cola. One may repeat this throughout the day, especially before and after meals.

2.4 Stent retrieval techniques

• The most commonly used method for retrieving stents is to grasp the proximal end of the stent with forceps or endoscopic snares, and then to pull out the endoscope, stent, and forceps/snare as one unit. Injury to the gastric or esophageal mucosa may occur and an overtube or a retrieval hood can be used to minimize this.
• The stent may be removed using a regular upper endoscope. Some endoscopists prefer using the double-channel therapeutic endoscope with two rat-tooth forceps or a rat-tooth forceps and a snare for stent removal.

2.5 Outcome data (efficacy)

• Technical success rates for placement of esophageal SEMS is close to 100%. Placement of SEPS (Polyflex) is more cumbersome and the technical success rate is reportedly lower than that of SEMS (approximately 85%).
• Rapid and prolonged improvement of dysphagia occurs in the majority of patients.
• Polyflex has higher migration rates compared to SEMS, especially when placed across the GE junction.
• Migration rates are higher with benign disease (30–70%) and efficacy is significantly lower. Some studies report long-term improvement in as few as 6% of patients.
• Although the Alimaxx-E stent is not FDA-approved for removability, it is the only SEMS that has an indication for removability. It is currently being widely used to treat both malignant and benign diseases of the esophagus. The stent appears easier to remove if it has been in place for a shorter period of time (e.g. 4–6 weeks).

Box 2 Take home points

• Newer stents (SEMS and SEPS) are superior to the obsolete semi-rigid plastic stents.
• The various SEMS are equivalent in technical success, efficacy, and complication rates when used for malignant strictures.
• The choice of a particular SEMS depends on device availability, familiarity and personal preference.
• SEPS is approved for removability.
• Benign strictures of the esophagus may be treated with either the Polyflex or the Alimaxx-E stents.
• Migration rates are higher when treating benign strictures.

2.5.1 Fistula formation

• This typically occurs between the esophagus and the respiratory tract. Most common etiologies include esophageal carcinoma, bronchogenic carcinoma, radiation therapy, laser therapy, and esophageal stents. This latter occurrence is due to pressure necrosis at the edge of a previously placed SEMS (due to high radial expansive force).
• Endoscopic placement of a covered SEMS is currently the primary and preferred form of therapy of malignant esophagorespiratory fistula with clinical success rates of 80–100%.
• Patients with persistent ERF may benefit from parallel stent placement: placement of a stent in the esophagus in combination with another stent in the trachea and/or bronchi.

2.5.2 Parallel stent placement

• As mentioned above, this may be performed for non-healing esophagorespiratory fistula.
• Esophageal cancer may invade/encroach the trachea causing dyspnea. In addition, mediastinal tumors causing extrinsic esophageal compression may also cause tracheal/bronchial compression. These patients are best treated with parallel stent placement because of risk of respiratory compromise. Place the tracheal or bronchial stent first.
• Proximal esophageal stents may compress the trachea. A low index of suspicion for tracheal compression is advocated in these patients, especially if they develop dyspnea.
• Complications, including fatal complications, occur more commonly with parallel stent placement because of tissue necrosis caused by the radial expansive force of both stents.

2.5.3 Proximal esophageal carcinoma

• Several small studies have shown that placing esophageal stents very close to the upper esophageal sphincter is feasible. The rate of efficacy is decreased, and there is a greater incidence of foreign body and globus sensation (8%) compared to more distal stents.
• If one chooses to place a stent in the cervical esophagus, close to the upper esophageal sphincter, choose a stent with the following favourable characteristics:

image Minimal to no foreshortening and a proximal release system to ensure precise deployment
image Small body diameter of 18 mm or less to minimize globus sensation
image Compliant characteristics in order to conform to the proximal esophageal anatomy
image 1–2 mm should be left between the upper esophageal sphincter and the proximal margin of the stent.

2.5.4 Extrinsic compression

• Esophageal stents have been used for palliation of malignant esophageal obstruction due to extrinsic lesions with favorable results.
• The degree of clinical improvement in such is significantly less than that in patients with malignant esophageal obstruction due to intrinsic lesions.

2.6 Complications

Early (or procedure-related) complications of esophageal stent placement occur in 10% of procedures and consist of chest pain, aspiration pneumonia, stent misplacement (can be minimized by choosing a stent 4 cm longer than the length of the stricture) and perforation. Late complications occur in 35–45% of patients and consist of gastrointestinal bleeding, development of ERF, stent migration, food bolus impaction, gastroesophageal reflux, and tumor overgrowth at either end of the stent. Stents placed across the gastroesophageal junction have higher complication rates when compared to stents placed in the mid-esophagus. In like manner, there is a statistically significant increased rate of life-threatening complications and associated increased mortality rate when placing stents in patients with a prior history of chemotherapy or radiotherapy. It appears that tissue integrity is compromised with administration of chemotherapy or radiation therapy, and this predisposes SEMS patients to a higher risk of life-threatening complications. Tumor ingrowth is a late complication that has been reduced with the advent of silicone or polyurethane covering, but unfortunately at the risk of increased stent migration (16% migration rate for covered SEMS vs 4% for uncovered SEMS). Treatment options for management of tumor ingrowth include laser therapy, injection therapy, electrocoagulation, photodynamic therapy, argon plasma coagulator, and placement of an overlapping second SEMS.

image Clinical Tips

• When placing a stent across the gastroesophageal junction, choose a large diameter stent to decrease migration risk.
• An antireflux stent may be useful.

3 Duodenal stenting

3.1 General concepts

• Patients with gastric outlet obstruction were historically treated with gastrojejunostomy with or without choledochojejunostomy.
• A recent systematic review of palliative stent placement versus open or laparoscopic gastrojejunostomy for the treatment of patients with malignant gastric outlet obstruction suggested that endoscopic treatment is the preferred modality in patients with short life expectancy (<6 months).
• The two FDA-approved duodenal stents are uncovered and can be placed through the working channel of a therapeutic endoscope (need a working channel ≥3.8 mm).
• It is frequently not possible to traverse the stricture with the endoscope since a therapeutic endoscope is usually warranted.
• Duodenal stents are best placed under fluoroscopic guidance.
• There is usually no need to aggressively dilate the stricture in order to minimize risk of perforation.
• Duodenal stents are not used for benign disease.
• Patients with malignant duodenal obstruction often have or are at risk for biliary obstruction. Consider placing a biliary SEMS prophylactically before placing a duodenal SEMS.
• Duodenal strictures are dilated (18–22 mm) only if biliary drainage is to be performed, since access to the papilla requires the use of a large diameter therapeutic duodenoscope.

3.2 FDA-approved expandable duodenal stents

See Table 2.

Table 2 FDA-approved expandable duodenal stents

image

3.3 Technique of stent placement

• The insertion procedure of a duodenal stent is similar to that of an esophageal stent (Figs 4, 5).
• Patients with gastric outlet obstruction have high gastric residuals and suction of gastric contents should be performed if possible, to minimize aspiration risk and optimize visualization.
• Patients should be in supine or prone position to optimize fluoroscopic visualization.
• If a patient is deemed high risk for aspiration, consider endotracheal intubation prior to stent placement.

image

Figure 4 Insertion of duodenal stent.

image

Figure 5 Duodenal stenting. Tumor ingrowth in a previously placed duodenal stent. A wire is placed across the stent under (A) endoscopic and (B) fluoroscopic guidance. A second, followed by a third stent is deployed (C). (D) The final radiographic image with three duodenal stents.

(Courtesy of Dr Ian Penman.)

image Clinical Tips

• The status of the biliary tree should be assessed before gastroduodenal stent placement.
• Placement of SEMS across the papilla will render endoscopic biliary access difficult, if not impossible.

• If the tumor is located in the proximal duodenum without involvement of the papilla, a stent that is long enough to cross the lesion should be chosen, but not excessively long which will prevent access to the papilla. Therefore, accurate assessment of the length and location of the malignant stricture is important.
• The stricture may then be accessed with a standard biliary balloon catheter over a guidewire under fluoroscopic guidance. Injecting dye through the stricture may help delineate the length, geometry, and extension of the stricture.
• The selected stent should be about 4 cm longer than the stricture.
• Prior to discharge, patients should be advised to advance from liquids to solids as tolerated and to avoid leafy vegetables, which may result in stent occlusion.

image Clinical Tips

• An expandable metal biliary stent should be placed before the duodenal stent is placed if there is known or impending biliary obstruction.
• To treat biliary obstruction after placement of a duodenal stent, a percutaneous transhepatic approach is usually required.
• Stenting of both the duodenum and the bile duct is the non-surgical equivalent of a traditional double surgical bypass (gastrojejunostomy and choledochojejunostomy).

3.4 Outcome data (efficacy) and complications

One systematic review that included 606 patients summarized the published evidence of the effectiveness and safety of gastroduodenal stenting. Technical success and clinical success were achieved in 97% and 89% of patients, respectively. There was no procedure-related mortality and serious complications (bleeding and perforation) were observed in 1.2% of patients. In addition, migration and obstruction (primarily due to tumor ingrowth) occurred in 5% and 18% of patients, respectively.

Jejunal stents may also be placed. These can sometimes be placed with a pediatric colonoscope; however, augmented enteroscopy with double balloon, single balloon or spiral enteroscope (Fig. 6) provide a stable platform for stent insertion.

image

Figure 6 Jejunal stent insertion using spiral enteroscopy. (A) Small-bowel obstruction with tumor. (B) Deployment of SEMS using Endo-Ease Discovery overtube. (C) Endoscopic image of deployed SEMS. (D) Radiographic image of deployed SEMS.

(Courtesy of Dr Anne Marie Lennon, from Lennon AM, Chandrasekhara V, Shin EJ, Okolo PI. Spiral-enteroscopy-assisted enteral stent placement for palliation of malignant small-bowel obstruction. Gastrointestinal Endoscopy 2010; 71(2): 422-425.)

4 Colonic stenting

4.1 General concepts

• All four FDA-approved colonic stents are SEMS.
• All colonic stents currently in use are uncovered because the use of covered stents in the colon is associated with an unacceptably high migration rate.
• Two SEMS can be placed through the scope (TTS) and the other two are non-TTS.
• Few data exist on the use of colonic stents for the treatment of benign diseases of the colon.
• Main indications for colonic stenting are:

image Bridge to surgery in patients with colorectal cancer (CRC) who present with total or subtotal colonic obstruction.
image Palliation of inoperable malignant colorectal obstruction.

Box 3 Rationale for colorectal stenting as a bridge to surgery

• Of patients with CRC, 7–29% present with or develop colorectal obstruction.
• Field contamination hazard exists with emergency surgery.
• Patients are usually malnourished and have dilated colons, both of which increase the surgical risk.
• Avoid colostomy: colostomy management is cumbersome to some patients, it worsens QoL, and its closure has significant morbidity and mortality of 37% and 7%, respectively.
• Avoids multistep surgery.
• Possible laparoscopic approach.
• Preoperative colonoscopy to clear the colon of synchronous tumors and more proximal strictures.

• Smaller diameter stents are appropriate for proximal colonic stenting because the stool is still liquefied and smaller diameter stents may carry a lower perforation risk. Larger diameter stents are more appropriate for distal colonic strictures to prevent solid stool impaction within the stent lumen
• Enema preps suffice for patients with total colonic obstruction or distal colonic obstruction. All other patients require standard colonoscopy preparation.

4.2 FDA-approved expandable colonic stents

Table 3.

Table 3 FDA-approved expandable colonic stents

image

4.3 Technique of stent placement (Figs 7, 8)

• Placement of colonic stents is more technically demanding than esophageal and gastroduodenal stents. Endoscopic placement alone can be performed for traversable strictures. Because of the frequent complexity of colonic strictures, colonic angulations, and the presence of stool, the use of fluoroscopic guidance is advocated.
• For endoscopic placement alone, a small calibre endoscope is used to traverse the stricture. The stricture can be carefully dilated to 12–14 mm if needed. The geometry and length of the stricture are then determined with the endoscope. Subsequently, the guidewire is placed through the stricture and the scope is withdrawn. Only non-TTS stents may be used since TTS stents do not fit into the therapeutic channel of a small calibre endoscope. The stent is then placed over the guidewire, the endoscope is positioned just distal to the lesion, and the stent is deployed under endoscopic guidance.
• Combined endoscopic and fluoroscopic placement obviates passage of the endoscope across the stricture. A therapeutic channel endoscope and a TTS-stent may be used. A biliary balloon catheter is passed through the stricture over a stiff guidewire and water-soluble dye is injected to delineate the geometry and length of the stricture. The stent is then placed under endoscopic and fluoroscopic guidance as described previously.
• The stent chosen should be 4 cm longer than the stricture.
image

Figure 7 Insertion of colonic stent.

image

Figure 8 Colonic stent insertion. (A) Malignant colonic obstruction (B) that was palliated with placement of a self-expandable metal stent.

image Clinical Tips

• If the stricture lies within or close to an angulation, then the ends of the stent may be oriented towards the colonic wall after deployment, preventing adequate passage of fecal material through the stent. If this occurrence is anticipated, then it may be preferable to use a longer stent than expected to ensure that the ends of the stent are directed towards the lumen.
• TTS-stents should be used for right sided lesions.

4.4 Outcome data (efficacy) and complications

• Table 4 summarizes pooled analysis from a 14-year data collection that included 1198 patients.
• SEMS may be used effectively to treat patients with malignant rectal obstruction within 5 cm from the anal verge (anal pain occurs in 62% of patients).
• SEMS may be used effectively to treat patients with malignant proximal colonic obstruction (technical success 95%, clinical success 85%).
• Colonic stents are generally less effective for palliation of colorectal obstruction due to extrinsic malignant obstruction.

Table 4 Pooled analysis of technical and clinical success rates

image

image Clinical Tips

• SEMS may be used effectively to treat benign colorectal obstruction with relief of obstruction in 95% of cases.
• Serious complications occur in about 40% of patients, most of which occur 7 or more days after stent placement.
• If SEMS are used for benign colorectal disease, surgery should be planned soon after stent placement (bridging).
• See Table 5 for colorectal stent complications.

Table 5 Preoperative and palliative colorectal stents complications (n = 826)

Mortality 0.3%
Morbidity 5–10%
Perforation 3%
Migration 9%
Bleeding/pain/tenesmus 10%
Re-obstruction 9% (tumor ingrowth/overgrowth 74%, fecal impaction 20%, migration 6%)

Further Reading

Baerlocher MO, Asch MR, Dixon P, et al. Interdisciplinary Canadian guidelines on the use of metal stents in the gastrointestinal tract for oncological indications. Can Assoc Radiol J. 2008;59:107-122.

Baron TH. Expandable gastrointestinal stents. Gastroenterology. 2007;133:1407-1411.

Baron TH. Expandable metal stents for the treatment of cancerous obstruction of the gastrointestinal tract. N Engl J Med. 2001;344:1681-1687.

Dormann A, Meisner S, Verin N, et al. Self-expanding metal stents for gastroduodenal malignancies: systematic review of their clinical effectiveness. Endoscopy. 2004;36:543-550.

Eloubeidi MA, Lopes TL. Novel removable internally fully covered self-expanding metal esophageal stent: feasibility, technique of removal, and tissue response in humans. Am J Gastroenterol. 2009;104:1374-1381.

Mougey A, Adler DG. Esophageal stenting for the palliation of malignant dysphagia. J Support Oncol. 2008;6:267-273.

Nathwani RA, Kowalski T. Endoscopic stenting of esophageal cancer: the clinical impact. Curr Opin Gastroenterol. 2007;23:535-538.

Sebastian S, Johnston S, Geoghegan T, et al. Pooled analysis of the efficacy and safety of self-expanding metal stenting in malignant colorectal obstruction. Am J Gastroenterol. 2004;99:2051-2057.

Tierney W, Chuttani R, Croffie J, et al. Enteral stents. Gastrointest Endosc. 2006;63:920-926.

7.4 Argon plasma coagulation

Vikesh K. Singh, Jean Marc Canard

Summary

1. General principles 179
2. Equipment 179
3. Technique 179
4. Clinical applications 181
5. Complications 183

Key Points

• Argon plasma coagulation (APC) is a non-contact monopolar electrocoagulation technique.
• APC probes can direct high frequency current towards tissue in a parallel or perpendicular fashion.
• The depth of coagulation is dependent on the properties of the target tissue, the generator power setting, the distance between the probe and tissue, and duration of current application.
• Power settings of 40–60 W and gas flow rates of 1 L/min are used for superficial hemostasis and ablation of vascular ectasias. Power settings of 70–90 W are used for tissue ablation.
• APC is used for the treatment of gastric antral vascular ectasia, angiodysplasia, radiation proctopathy, and residual adenomatous tissue seen after piecemeal colonic polypectomy.

1 General principles

Argon plasma coagulation (APC) is a non-contact monopolar electrocoagulation technique, initially used for endoscopic applications in the digestive tract in 1994 by Grund and Farin. APC is used primarily for superficial hemostasis and tissue ablation.

The probe of the delivery catheter contains a tungsten electrode through which a high frequency electric current is delivered to the target tissue using ionized argon gas (argon plasma). This results in the coagulation of the target tissue. The depth of coagulation is dependent on the power of the electrosurgical generator, the distance between the probe and the target tissue, and the duration of application. The physical properties of the treated tissue also affects the depth of tissue injury. Treated tissue demonstrates three zones of effect. The outermost zone, closest to the probe, is the dessication zone followed by the coagulation and devitalization zone (Fig. 1).

image image

Figure 1 (A) The argon beam follows the path of least electrical resistance and; therefore, will direct itself away from treated tissue to adjacent areas of untreated tissue. This property allows administration of current in both a perpendicular and parallel manner from the tip of the catheter probe. (B) Three zones of effect: (1) dessication (2) coagulation (3) devitalization.

2 Equipment

APC requires a monopolar electrosurgical generator, argon gas source, gas flow meter, flexible delivery catheter, foot activation pedal, and grounding pads.

There are two manufacturers of APC generators (Conmed, Utica, NY and ERBE Electromedizen, Tubingen, Germany). Power can be adjusted between 0 and 150 W and gas flow rates between 0.5 and 7.0 L/min. The flexible delivery catheters are disposable and are available in a 1.5 mm, 2.3 mm, and 3.2 mm diameters with lengths of 220 cm and 300 cm. The most commonly used is the 2.3 mm diameter, 220 cm long catheter. The wider diameter catheters are used if a larger treatment area is required. The 300 cm catheters are used for treatment of lesions in the small bowel during push enteroscopy. Catheters can direct current in a parallel or ‘forward firing’ versus perpendicular or ‘side firing’ manner, in relation to the longitudinal axis of the catheter. The ‘side firing’ probe can be used for lesions which are difficult to access, such as those located behind a fold or around a sharply-angled corner (Fig. 2). The foot activation pedal synchronizes delivery of the current and argon gas which ionizes the argon gas and allows current to be delivered to the target tissue.

image image image

Figure 2 Role of APC in areas which are difficult to access. (A) APC is very useful for treating areas in the retroflexed position. It has the advantage over other modalities of not damaging the endoscope. (B) APC of the cardia. (C) APC is useful for inaccessible blind areas, e.g. behind a fold.

Grounding pads are required as APC is a monopolar coagulation technique necessitating that the current circuit is completed via a return electrode.

3 Technique

• Patients requiring colonic APC should be given a full bowel preparation prior to the procedure, even if therapy is to only be directed to the rectum because there is a risk of explosion. It is also imperative to aspirate the gas that is released in the colon during an APC procedure as failure to do so can result in colonic distension.
• Apply the grounding pad. Care must be taken in patients with cardiac pacemakers and defibrillators when using APC. The grounding pad should always be placed away from these devices.
• Check the generator and gas flow settings are appropriate for the desired indication prior to administering APC (Table 1).
• Flush the probe before firing. This should be followed by test firing the probe before inserting the probe into the operating channel of the endoscope.
• Insert the probe until it protrudes slightly from the operating channel with at least one black mark on the probe visible to prevent injury to the tip of the endoscope.
• The probe should be kept 1–2 mm from the target tissue. If the probe is at a distance greater than this, ionization of the argon gas will not occur. Probe should initially touch the target tissue and then withdrawn prior to firing to ensure the proper distance.
• Take care to make sure that an actively firing probe does not touch the mucosa, as this increases the risk of perforation and allows for the passage of non-ionized gas into open blood vessels.
• Avoid repeatedly firing in the same area as this increases the risk of perforation.
• If an increased distance is required between the probe and the target lesion, increasing the power, as opposed to the gas flow rate, will increase the length of ionized argon gas arc. Alternatively, a ‘side-firing’ probe can be used, particularly if the target lesion is located lateral to the probe or is behind a fold.
• Avoid contact with the mesh from a metal stent as the wire may melt.
• Avoid contact with a clip, as conduction of current can cause secondary perforation (particularly in the duodenum).

Table 1 APC setting

image

image Clinical Tips

How to decrease risk of perforation

• Always apply APC under direct visual control.
• Start with multiple, short activations before using long activations.
• Direct contact of the probe with the mucosa increases the risk of perforation and should be avoided.
• Avoid repeated treatment of the same area.
• Avoid excessive insufflation by asking the nurse to monitor for abdominal distension and suctioning regularly.
• Limit the power of the generator to the level required for adequate coagulation of the target tissue.
• Patients undergoing APC in the colon, even on the rectum, MUST have a full bowel preparation.
• Avoid contact with clips to avoid secondary perforation.

4 Clinical applications

4.1 Radiation proctopathy

APC has been shown to be an effective treatment for gastrointestinal bleeding associated with radiation proctopathy in several case series studies (Fig. 3).

• Patients must have a full bowel preparation, even if only treating the rectum, as there is an increased risk of explosion in an unprepared colon.
• Care should be taken to avoid treatment close to the dentate line.
• Power settings of 40–60 W and gas flow rates of 1–1.5 L/min have been evaluated.
• Treatments are repeated every 1–2 months, with between 1 and 3 sessions usually required.
image

Figure 3 Radiation proctopathy. (A) Rectum with active bleeding from radiation proctopathy. (B) Following APC.

Complications include post procedure pain, particularly when treatment is administered close to the dentate line. Rare complications which have been reported include transient urinary retention, rectovaginal fistula, and rectal strictures. There are currently no randomized prospective trials comparing APC with laser and medical therapies.

4.2 Vascular lesions

APC is an effective treatment for gastric antral vascular ectasia (GAVE) (Fig. 4) and angiodysplasia (Fig. 5), and prevents recurrent bleeding associated with these lesions.

image

Figure 4 Classic appearance of gastric antral vascular ectasia.

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Figure 5 APC treatment of angiodysplasia. (A) Small angiodysplastic lesion before coagulation. (B) Following APC.

GAVE (Fig. 4) is an uncommon cause for upper gastrointestinal blood loss associated with cirrhosis and other chronic diseases (Box 1). Involvement of the antrum can be patchy or diffuse. Patients often present with iron deficiency anemia. Improvements in hemoglobin levels and a decrease in transfusion requirements are seen in most patients. However, recurrence can be seen in 30–40% of patients between 20 and 30 months after therapy, which often requires further APC treatment.

• Power settings between 40 and 100 W have been used.
• Treatments are repeated every 1–2 months, with between 2 and 3 sessions usually required.

Box 1 Conditions associated with GAVE

• Cirrhosis.
• Collagen vascular disease (e.g. scleroderma).
• Ischemic heart disease.
• Chronic renal failure.
• Pernicious anemia.
• Bone marrow transplant recipients.

Angiodysplasias (Fig. 5) can be found throughout the gastrointestinal tract and are effectively treated with APC. Angiodysplasias can be found throughout the gastrointestinal tract and are effectively treated with APC.

• The 300 cm probes will often be required to ablate angiodysplasias of the mid and distal small bowel during push enteroscopy.
• Successful ablation of angiodysplasia(s) is indicated by the presence of a white coagulum after treatment.
• APC treatment of diffuse angiodysplasias require moving a probe in an side-by-side and up-and-down arc which is commonly referred to as ‘painting’ the lesion with short, 1–2 s applications.
• For cecal angiodysplasias, consider submucosal injection with saline and/or dilute epinephrine prior to treatment to reduce the risk of perforation.
• APC therapy significantly improves hemoglobin values and is associated with lower rates of overt bleeding in about 85–90% of patients.

4.3 Treatment of remnant polypoid tissue after piecemeal resection of large colonic polyps

APC has been shown to be effective in devitalizing any remnant polypoid tissue at the rim and base of a piecemeal polypectomy site. Polyps which are large (>1.5 cm), flat, extended, and/or located behind a fold or an angulated area of the colon often require piecemeal resection techniques. Patients undergoing APC have been shown to have significantly fewer recurrences. Treatment should be focused along the rim of the polypectomy site but short applications at the base can also be used. However, there has only been one small randomized study demonstrating these results.

4.4 Other applications

APC has been used for palliative debulking of obstructive tumors of the esophagus (Figs 6, 7), stomach, ampulla, and rectum (Figs 8, 9). While symptomatic improvement is seen in >90% of patients, multiple treatment sessions are often required. While there have been few randomized studies, a large series of patients with obstructive esophageal and cardia tumors underwent APC with maintenance of luminal patency in 64% of patients until death.

image

Figure 6 APC for the palliative treatment of an esophageal tumor. Start at the most distal extent of the tumor and work proximally.

image

Figure 7 (A) Esophageal cancer pre-treatment. (B) APC treatment of the tumor. (C) Esophageal cancer following treatment.

image

Figure 8 Palliative treatment of a tumor in the sigmoid colon. Start at the most distal extent of the tumor to avoid coagulation in the wrong direction.

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Figure 9 APC treatment for palliation of rectal cancer. (A) Rectal cancer pre treatment. (B) After the first session of APC. (C) Prior to commencing second session of APC. (D) Following second session. (E) Appearance during treatment. (F) Appearance after the session. (G) Appearance before the last session. (H) Last session of APC. (I) Scar with complete destruction. As a result of this example, YAG laser has been replaced with APC.

APC has also been studied as therapy for bleeding peptic ulcers but concerns center on its inability to seal a bleeding vessel and the risk of precipitating further bleeding, especially from arteries >1 mm. Another potential role for APC in the future may be for shortening or trimming metal stents which have become displaced over time to prevent perforation or bleeding.

5 Complications

• Perforation can occur with APC (0.2% in one large study), particularly when treating lesions in the right colon. It is associated with increased power setting, long duration of application, and short probe to tissue distance.
• Abdominal distension is not uncommon as even a few minutes of application can lead to significant quantities of argon gas release.
• Colonic explosion has been described in patients who had not undergone a full bowel preparation or if a fermentable, sugar-containing laxative is used prior to the procedure.
• APC can also cause a neuromuscular stimulation which can sometimes be painful.
• Rare complications include transient urinary retention, rectovaginal fistula, rectal strictures and subcutaneous empyema.

Further Reading

Canard JM, Fontaine H, Vedrenne B. Electrocoagulation par plasma d’Argon: première expérience française rapportée [Argon plasma electrocoagulation: first French experience reported]. Gastroenterol Clin Biol. 1997;21:A36.

Canard JM, Vedrenne B. Clinical applications of Argon plasma coagulation in gastro-intestinal endoscopy: has the time come to replace the laser? Endoscopy. 2001;33(4):353-357.

Canard JM, Vedrenne B, Bors G, et al. Résultats à long terme du traitement des rectites radiques hémorragiques par la coagulation au plasma d’Argon [Long-term results of the treatment of hemorrhagic radiation proctitis by argon plasma coagulation]. Gastroenterol Clin Biol. 2003;27:455-459.

Farin G, Grund KE. Technology of argon plasma coagulation with particular regard to endoscopic applications. Endosc Surg Allied Technol. 1994;2:71-77.

Dumot JA, Greenwald BD. Argon plasma coagulation, bipolar cautery, and cryotherapy: ABCs of ablative techniques. Endoscopy. 2008;40:1026-1032.

Ginsberg GG, Barkun AN, Bosco JJ, et al. The argon plasma coagulator. Gastrointest Endosc. 2002;55:807-810.

Manner H. Argon plasma coagulation therapy. Curr Opin Gastroenterol. 2008;24:612-616.

Morris ML, Tucker RD, Baron TH, et al. Electrosurgery in gastrointestinal endoscopy: principles to practice. Am J Gastroenterol. 2009;104:1563-1574.

Postgate A, Saunders B, Tjandra J, et al. Argon plasma coagulation in chronic radiation proctitis. Endoscopy. 2007;39:361-365.

Selinger CP, Ang YS. Gastric antral vascular ectasias (GAVE): an update on clinical presentation, pathophysiology, and treatment. Digestion. 2008;77:131-137.

Suzuki N, Arebi N, Saunders BP. A novel method of treating colonic angiodysplasias. Gastrointest Endosc. 2006;64:424-427.

Vargo JJ. Clinical applications of the argon plasma coagulator. Gastrointest Endosc. 2004;54:81-88.

7.5 Management of ingested foreign bodies

Jean-Christophe Létard, Marcel Happi Nono

Summary

Introduction 186
1. Clinical assessment 186
2. Imaging 186
3. Timing of endoscopy 187
4. Equipment 187
5. Endoscopy technique 188
6. Complications 190
7. Ingestion of toxins 190

Key Points

• 80–90% of foreign bodies and food bolus impactions pass spontaneously.
• Always assess for perforation.
• Drug packets should never be removed by endoscopy.
• Have a low threshold for seeking anesthetic input to protect the airway.
• Test the instrument you are going to use to remove the foreign body before performing endoscopy.

Introduction

Removal of foreign bodies is a common procedure for gastroenterologists. In the majority of cases the type of foreign body ingested can be determined by a careful history or by speaking to relatives or friends.

The majority (80%) of foreign bodies are ingested by children, with a peak between the ages of 6 months to 3 years. Prisoners, psychiatric patients, alcoholics, patients with a history of digestive surgery or malformations (rings or webs) and edentulous elderly patients are at risk of foreign body ingestion.

The commonest sites for obstruction are the glottis, valleculae, larynx, cricopharyngeal muscle, aortic arch, lower esophageal sphincter, pylorus, ileocecal valve or anus or at areas associated with pathology (i.e. esophageal stricture).

Once in the stomach, most foreign bodies pass through the GI tract without complication within 1–2 weeks (Box 1). Exceptions to this rule are objects longer than 5 cm or wider than 2 cm, which may not pass through the pylorus or duodenum.

Box 1 Outcome of ingested foreign bodies

• 80–90% pass spontaneously.
• 10–20% require endoscopy.
• <1% require surgery.

If endoscopy is required it is successful in greater than 95% of cases. The majority of series report morbidity rates of less than 5% and usually 0%.

1 Clinical assessment

1.1 Foreign body lodged in the respiratory tract

This should be suspected if the patient has difficulty breathing or has wheezing.

1.2 Foreign body in the upper gastrointestinal tract

The ingestion of a foreign body can cause retrosternal pain, odynophagia, dysphagia, hypersialorrhea and sometimes vomiting in the case of large, obstructive objects. Subcutaneous emphysema can occur with esophageal perforation, while peritonitis suggests small or large bowel perforation. Sharp objects, such as toothpicks, meat or fish bones, razors, lapel badges, dentures or needles, can cause bleeding or perforation.

A high degree of suspicion is required in children or mentally impaired adults as 20–38% of children are asymptomatic, while up to 40% of children or non-communicative adults have no history of foreign body ingestion.

2 Imaging

Plain radiographs in two planes should be performed promptly. Anteroposterior and lateral radiographs of the chest and abdomen should be performed. This allows for localization of the foreign body and will also detect the presence of pneumomediastinum, pleural effusion or subcutaneous air, which are associated with perforation. Anteroposterior and lateral films of the neck and chest should be performed if there is a suspicion of a foreign body in the esophagus versus the trachea (Fig. 1).

image

Figure 1 Anteroposterior CXR with characteristic image of a battery in the esophagus. Note the ‘Halo’ sign which is seen because the two sides have a different diameter. If the battery is in the trachea, it would be seen in profile.

image Clinical Tip

Respiratory tract or esophagus?

A coin with a round face on AP film is usually in the esophagus; if it has a linear surface, it is most likely the trachea owing to the orientation of the vocal cords (see Fig. 1).

Not all foreign bodies are visible on a plain radiograph. Radio-opaque objects are visible; however, non-radio-opaque objects will not be seen (Table 1). Thus, plain radiographs will miss 50–80% of swallowed bones later identified on endoscopy. Computerized tomography is superior to plain radiographs, and will identify the location of 80–100% of foreign bodies. Barium studies should not be performed due to risk of acute pulmonary edema if aspiration occurs.

Table 1 Radiolucency of foreign bodies

Radiolucency Foreign body
Radio-opaque Metal (such as coins), batteries, needles and pins
Not always visualised Cartilage, meat or fish bones, pieces of plastic and occasionally glass or alloy are not always visualized on plain films
Radiolucent Food

3 Timing of endoscopy

Most foreign bodies pass spontaneously and do not require endoscopic intervention. Patients who are symptomatic usually require endoscopy.

Foreign bodies obstructing the hypopharynx, sharp or pointed foreign bodies and batteries located in the esophagus should be removed as an emergency.

The majority of foreign bodies which reach the stomach can be watched. Exceptions to this rule are:

• Foreign bodies >2 cm thick or >5 cm long, as they are unlikely to pass through the pylorus and ileocecal valve, and will require endoscopic removal.
• Sharp objects.

4 Equipment

• Diagnostic and therapeutic upper endoscopes should be available
• Rat-tooth or crocodile type forceps (Fig. 2)
• Tripod forceps (Fig. 2)
• Biopsy forceps (Fig. 3)
• Polypectomy snare
• Dormia and Roth baskets
• Overtubes (Fig. 4)

image Standard (extend past the upper esophageal sphincter)
image 45–60 cm (extend past the lower esophageal sphincter)
• Rubber hood (Fig. 5).
image

Figure 2 Instruments used for removal of foreign bodies. (A) Removal of an esophageal foreign body using tripod forceps. (B) Crocodile forceps. (C) Removal of a coin using rat-tooth forceps.

image

Figure 3 Extraction of a ring using a thread and biopsy forceps passed through the ring.

image

Figure 4 Removal of a sharp foreign body. An overtube should be used to withdraw a sharp foreign body.

image

Figure 5 Removal of long foreign body. A rubber hood or overtube should be used to remove objects which are longer than 45 cm.

image Clinical Tip

Endoscopic ‘dry run’

Simulate foreign body removal outside the body prior to endoscopy with the object to determine what technique and equipment work best.

5 Endoscopy technique

General anesthesia is required in pediatric patients or in those with complex or multiple foreign bodies.

Endoscopic strategy depends on the size of the foreign body ingested, its shape, the material it is made of, the anatomical location of the obstruction, the experience of the endoscopist and the technical resources available. Foreign bodies located above the cricopharyngeal muscle should be removed by laryngoscopy. Foreign bodies below this level should be removed with endoscopy.

Overtubes can be used to extract foreign bodies whose removal could cause bleeding or perforation, such as pointed, sharp or long foreign bodies (Fig. 4). Standard overtubes extend past the upper esophageal sphincter, while longer overtubes (45–60 cm) pass the lower esophageal sphincter and are used to remove sharp objects from the stomach. Overtubes are also useful where there is a risk of aspiration or where multiple attempts will be made to remove a foreign body (i.e. food bezoars in non-intubated patient). Overtubes are rarely used in children, given their diameters.

5.1 Food bolus obstruction

Food impaction occurs in patients with anatomical anomalies such as web, ring or stricture or in patients with esophageal cancer. In the absence of esophageal obstruction, an endoscopy should be performed within 24 h. Endoscopy is successful in 95–99% of cases. An attempt should be made to pass the endoscope between the esophageal wall and the food bolus and into the stomach. The angle of the gastroesophageal junction and the cause of the obstruction should be noted. The food bolus will sometimes pass into the stomach with this maneuver. If this fails, the endoscope can be repositioned and the food gently pushed into the stomach. This should not be attempted if there are bones within the food bolus, as these can perforate if pushed into the mucosa. If this is unsuccessful, the food bolus can be broken into smaller pieces. These smaller pieces can sometimes be gently pushed into the stomach or can be removed using a Roth net.

5.2 Bezoars

These are usually encountered in adults without teeth or with anatomical anomalies such as atresia, stenosis, diverticulum or cancer of the esophagus, hiatus hernia or Schatzki ring. They may cause nausea, vomiting or loss of appetite. There are three types of bezoars. Trichobezoars are concretions of hair found in women aged 10–19 years who practice trichophilia or trichophagy. Phytobezoars consist of vegetable matter. Lactobezoars occur in premature, low-birth-weight babies or infants fed for the first week of life with concentrated milk.

In the absence of bowel obstruction, wait 24 h before performing endoscopy. Fizzy drinks can be tried. Intravenous glucagon causes relaxation of the lower esophageal sphincter, and is effective in 30–50% of cases.

When endoscopy is required, an attempt should be made to pass the endoscope between the esophageal wall and the bezoars and into the stomach. The bezoar will often follow the endoscope into the stomach (Fig. 6). If this fails, or if the bezoar is large, it should be broken into smaller fragments, which can then be extracted with a basket or Roth net.

image

Figure 6 Bezoar in the stomach.

5.3 Round blunt foreign bodies

These are commonly swallowed in children aged between 6 and 12. Ingestion is asymptomatic in 16% of cases. In the remaining cases, the object will lodge at the level of the cricopharyngeal muscle (60–80% of cases), at the aortic arch (10–20%), or at the lower esophageal sphincter (5–20%).

The management of round, blunt foreign bodies (i.e. coins) depends on their size, the patient’s symptoms and the location. Objects which measure 2.5 cm or less will pass through the pylorus and may be watched (Table 2). If they are located in the esophagus, they should be removed if they have not passed within 24 h. If they are located in the stomach, they should be removed if they have failed to pass after 4–6 days. If the foreign body has passed through the pylorus, patients may be placed on a regular diet, with plain radiographs every week to confirm passage through the gut. Prokinetic medication has not been proved to be effective.

Table 2 Classification of lesions seen up to 24 h after caustic burn

Stage Endoscopic findings Management and outcome
0 Normal mucosa Excellent
I Mucosal erythema and edema Spontaneous recovery in 1–3 days
IIa Ulceration of the mucous membrane with exudates and bleeding Commence liquid diet and progress to solid after 48 h
No endoscopic follow-up necessary
IIb Circumferential or deep ulceration Major risk of stricture formation
Initiate nasoenteric feeding after 24 h with liquid at 48 h if clinically well
III Extensive necrosis High risk of perforation
Monitor carefully for 10 days
Surgery indicated

If endoscopy is required, most round, blunt objects can be removed using a Dormia basket, a Roth net, a polyp snare or forceps (Fig. 7). It is essential to ensure that the airway is protected from aspiration or inadvertent loss of the foreign body into the upper airways (i.e. coin).

image

Figure 7 Removal of a round metal object located in the stomach using a Roth net.

5.4 Batteries

Batteries are blunt objects which yield a ‘halo’ image on standard radiographs (Fig. 1), because they have two sides with different diameters. Their ingestion requires emergency treatment, as there is a high risk of perforation. Mucosal damage can occur in the esophagus in 1 h, muscular damage in 2–4 h, with perforation occurring in 8–12 h.

Batteries can be removed in a similar manner to round objects described in section 5.3. The airway should be protected by intubation or by using an overtube. The battery itself can be removed with a Roth net or basket. Graspers and forceps should be avoided to avoid puncturing the battery. Once they have passed into the stomach, approximately 85% pass spontaneously. In these cases, passage should be confirmed with serial radiographs. Surgery is indicated if the battery fails to pass within 3 days, or the patient develops severe abdominal pain.

5.5 Sharp foreign bodies

Sharp objects require emergency treatment if they are impacted in the esophagus, owing to the risk of perforation (15–35%) and hemorrhage. If they have passed through the pylorus, daily radiographs should be performed. Surgery is indicated if the sharp object has remained in the same place for more than 3 days.

To extract a sharp object, ensure that the blunt end of the object is closest to the endoscope, with the sharp end following. This is done to avoid damaging or perforating the mucosa while extracting the foreign body. These objects can usually be removed using a forceps, polypectomy snare, Dormia basket or Roth net. If there is significant risk of trauma, an overtube or rubber hood should be used (Fig. 4). An alternative that has been described uses a simple latex glove: the tip is cut off and secured with a thread to the distal end of the endoscope. The foreign body is grasped and the latex glove inverts around the foreign body as it comes through the lower esophageal sphincter.

image Clinical Tip

Always remove sharp objects blunt end first to avoid perforation.

5.6 Long foreign bodies

Long objects (>5 cm) need urgent endoscopy if they are in the esophagus or stomach. They are usually pens, spoons or toothbrushes. These should be maneuvered using a polypectomy snare so that the widest part is adjacent to the endoscope. The endoscope and the long foreign body should then be withdrawn. This should be done in combination with either an overtube or a rubber hood. An overtube is recommended if the object is >45 cm long (Fig. 5).

5.7 Body packages containing drugs

Body-packing involves the use of condoms filled with drugs such as cocaine or heroin. No attempt should be made to extract these drug packets since they may burst, causing a fatal overdose. Radiographs should be obtained daily, and surgery considered if perforation is suspected or if the packets remain for >48 h in the intestine.

5.8 Parasitic foreign bodies

Parasitic foreign bodies can occur, e.g. Ascaris lumbricoides trapped in the bile ducts or Anisakis impacted in the stomach wall. Endoscopic extraction is performed using forceps, a basket or occlusion balloon. It is important to ensure that the worm is completely extracted from the bile duct as remnants can lead to stone formation.

6 Complications

• Perforation

image Fever, pain, distension, crepitus in the neck or chest, swelling, guarding or rebound on abdominal examination should prompt investigation for perforation.
image Risk increases if objects are left in the esophagus for >24 hour.
image In patients with symptoms, the perforation rate is up to 5%, increasing to 35% for sharp foreign bodies.

• GI bleeding
• Fistulae
• Aspiration
• Abscess formation.

7 Ingestion of toxins

7.1 Ingestion of caustic toxins

Take a detailed history and examine the patient to assess:

• The type of product ingested, quantity, contact time and whether it is a recent acute event.
• Examine the patient to assess for laryngeal damage (hoarseness or dyspnea with stridor) or severe esophageal damage (odynophagia, hypersialorrhea or refusal of food) or perforation.
• Patients should be managed in an intensive or high dependency unit.
• Patients should be kept fasting and have serial chest and abdominal films.
• Proton pump inhibitors should be prescribed.

Basic (caustic cleaners, dishwasher products or hair conditioner), acidic products or bleaching agents are caustic to the pharynx, larynx, esophagus and also the stomach and duodenum (Fig. 8).

image

Figure 8 Caustic injury to the esophagus. (A) Caustic injury to the esophagus after ingestion of tetracycline. (B) Repeat endoscopy 3 weeks later.

7.2 Timing of endoscopy following ingestion of caustic substances

Upper endoscopy should be performed as soon as possible, and within 24 h of ingestion of a caustic substance. If upper endoscopy has not been performed within 48 h after ingestion, endoscopy should be deferred for 2 weeks due to the increased risk of perforation.

7.3 Contraindications and requirement for upper endoscopy

• Upper endoscopy is contraindicated if a perforation is suspected.
• In the absence of burns to the lips, buccal mucous membrane or oropharynx, caustic ingestion is rarely responsible for severe esophageal or gastric lesions and upper endoscopy is therefore unnecessary.
• The ingestion of certain metals (antimony, arsenic, barium, cadmium, chromium salts, copper salts and thallium) is not associated with caustic lesions and upper endoscopy is not indicated.

image Clinical Tip

Nasogastric intubation and emetics are contraindicated due to the risk of re-exposing the esophagus to caustic substance.

7.4 Endoscopy

• Endoscopy provides information on the early risk of perforation and on the late risk of stenosis.
• There is no requirement for antibiotic prophylaxis for endoscopy.
• There is currently no role for prophylactic esophageal stenting.
• Steroid injection is not recommended.
• Introduction of the endoscope should only be performed under visual control to minimize the risk of perforation.
• Note the appearance, location, extent and depth of caustic lesions (Table 2).

7.5 Post-endoscopy

• Prescribe proton pump inhibitors.
• Corticosteroid therapy at 2 mg/kg per day for 21 days seems effective for stage 2 burns and is believed to reduce the risk of stenosis due to scarring.
• Penicillamine or N-acetylcysteine may reduce collagen formation.

7.6 Special cases

7.6.1 Dilute bleach

Ingestion of dilute bleach (5–6% sodium hypochlorite) has a good prognosis. Endoscopy is performed only if there are ENT symptoms.

7.6.2 Formaldehyde

Formaldehyde does not destroy tissue; it acts as a fixative but the architecture of the tissues is preserved. Motility disappears and the mucous membrane gradually becomes grayish, discolored, rigid, and atonic. The examination needs to be repeated to assess the lesions.

7.6.3 Paraquat

The appearance of esophageal and gastric lesions after ingesting Paraquat (weed killer) indicates a poor prognosis and may precede sometimes fatal pulmonary fibrosis.

7.6.4 Meprobamate

The formation of gastric masses of meprobamate may cause prolonged poisoning, and even recurrences. They can be broken up endoscopically and removed via the upper route.

7.6.5 Potassium permanganate

The ingestion of potassium permanganate tablets involves a high risk of perforation for several hours afterwards. An emergency plain abdominal X-ray is useful as the tablets are radio-opaque. The mucous membrane is colored dark purplish-black, which may erroneously suggest digestive necrosis and in this case endoscopy will not allow correct evaluation of the lesions which are usually localized.

7.7 Complications from ingestion of caustic toxins

The ingestion of caustic substances can be complicated by perforation, mediastinitis or peritonitis. One of the commonest complications dealt with by an endoscopist is stricture formation.

• Stenosis appears in 10–15% of cases.
• Dilation should be deferred until 3–6 weeks after ingestion of caustic substance due to the risk of perforation.
• Treatment with temporary plastic stent insertion has been described.
• Pyloric stenosis with gastric outlet can develop months to years later.
• Surgery is necessary in some cases with replacement of the esophagus with colonic or jejunal interposition, or gastroplasty.
• There is a 1000-fold increase in the risk of squamous esophageal cancer in these patients.

Surveillance, commencing 15–20 years after caustic ingestion, and repeated every 1–3 years, is recommended.

Further Reading

Cotton PB. Overtubes (sleeves) for upper gastrointestinal endoscopy. Gut. 1983;24(9):863-866.

Kay M, Wyllie R. Pediatric foreign bodies and their management. Curr Gastroenterol Rep. 2005;7:212-218.

Webb WA. Management of foreign bodies of the upper gastrointestinal tract: update. Gastrointest Endosc. 1995;41:39-51.

Wells CD, Fleischer DE. Overtubes in gastrointestinal endoscopy. Am J Gastroenterol. 2008;103(3):745-752.

7.6 Endoscopy in obesity

Jean-Christophe Létard, Pierre-Adrien Dalbies, Ian Penman

Summary

Introduction 193
1. Endoscopy and bariatric surgery 193
2. Preoperative endoscopy 193
3. Postoperative endoscopy 193
4. Gallstone disease and ERCP following bariatric surgery 194
5. Endoscopic placement of intragastric balloons 195

Key Points

• Endoscopic or surgical management of obesity is only indicated after medical therapy has failed for patients with a BMI ≥40 (or 35 with co-morbidity).
• All patients with upper GI symptoms should undergo preoperative upper endoscopy.
• Endoscopy should also be performed in all patients in whom gastric bypass is planned irrespective of symptoms.
• A large hiatal hernia is a relative contraindication to gastric banding.
• Endoscopists should understand the different types of bariatric procedures, the resulting anatomy and the different complications that may arise from these.
• ERCP is technically difficult following Roux-en-Y gastric bypass and alternative means of diagnosis (MRCP) or treatment (percutaneous transhepatic cholangiography) should be considered. ERCP should be undertaken selectively and in specialist centers.

Introduction

Obesity is excess body fat and has a harmful effect on health resulting from an increased risk of cardiovascular disease (hypertension and cerebrovascular accidents), hyperlipidemia and type 2 diabetes. All cause mortality is also significantly higher in obese people. It is defined in clinical practice by the body mass index (BMI) which is calculated as weight/height2 (kg/m2). The WHO classification of obesity is shown in Table 1.

Table 1 WHO definitions of obesity

BMI Description Obesity grade
<18.5 Thin  
18.5–24.9 Normal  
25–29.9 Overweight  
30–39.9 Obese I (30–34.9), II (35–39.9)
≥40 Morbidly obese III

In the USA, 32% of the population are obese and 5% are morbidly obese. The treatment of obesity requires multidisciplinary management (nutritionist, endocrinologist, and psychiatrist) and it is only after dietary, pharmacological and behavioral therapy have been unsuccessful that endoscopic or surgical treatment should be offered.

image Clinical Tip

Endoscopic or surgical therapy may be indicated when medical management has failed in patients with a BMI of ≥40, or over 35 when there is major co-morbidity. Careful patient selection is vital.

1 Endoscopy and bariatric surgery

Two types of surgical procedures are performed:

• Restrictive procedures aiming to reduce gastric capacity (vertical banded gastroplasty (VBG) and laparoscopic adjustable gastric banding (LAGB)).
• Procedures combining a reduction in gastric capacity with maldigestion/malabsorption (Roux-en-Y gastrojejunal bypass, RYGB) or duodenal switch and biliopancreatic diversion (DS/BPD).

It is important for endoscopists to understand the different types of operation, the resulting anatomical alterations and the different complications that can arise following these procedures (Fig. 1).

image

Figure 1 Different bariatric surgical procedures. (A) Vertical banded gastroplasty. (B) Laparoscopic assisted gastric banding. (C) Roux-en-Y gastrojejunal bypass. (D) Duodenal switch and biliopancreatic diversion.

2 Preoperative endoscopy

All patients with upper GI symptoms should undergo endoscopy to detect and treat underlying conditions such as gastritis and gastric or duodenal ulceration. This may be impossible postoperatively, as the distal stomach and duodenum may be excluded and impossible to visualize endoscopically following RYGB or DS/BPD. A large hiatus hernia is also a relative contraindication to LAGB because of an increased risk of band slippage. Detection and eradication of Helicobacter pylori infection is also important as infection may increase the risk of anastomotic marginal ulcers. In contrast, there is less evidence to justify routine upper endoscopy in asymptomatic patients prior to bariatric surgery but it is still commonly performed.

3 Postoperative endoscopy

Clear understanding of the exact operation that has been performed is essential and personal discussion with the surgeon involved is often useful as the length of the Roux limb or afferent limb may vary from 50 to 150 cm in RYGB procedures and the size of the gastric pouch and the diameter of its outlet may also vary following VBG or LAGB.

image Warning!

Endoscopy should be undertaken with care in the early postoperative period, as excess air insufflation may disrupt newly created anastomoses. Contrast radiology studies may better delineate postoperative anatomy and are preferred when a leak or fistula is suspected.

When undertaking endoscopy, the size of any gastric pouch should be carefully documented, suture lines and anastomoses should be inspected for evidence of fistulation, stenosis or marginal ulceration, the latter occurring most commonly on the intestinal side. Stomas are generally 10–12 mm in diameter and stenosis is defined as a diameter <10 mm. The possibility of band slippage or erosion following LAGB should always be considered and looked for as these occur in 5–10% of patients. Anastomotic stenoses can be safely and gradually dilated without difficulty, either by bougienage or using balloon dilators. Dilatation should probably not be performed to >15 mm, as this may be associated with future weight gain.

image Warning!

Following RYGB the Roux limb may be tunnelled through the transverse mesocolon and can stricture at this point. Dilatation here is associated with a high risk of perforation and should be avoided.

4 Gallstone disease and ERCP following bariatric surgery

Both obesity and rapid weight loss are independent risk factors for cholelithiasis. After LAGB, ERCP can be performed normally but after gastric bypass procedures, it can be technically difficult or impossible. The likelihood of success is lower if the Roux and/or afferent limbs are long. Highly skilled endoscopists can achieve success in up to two-thirds of patients with experience, time and using a range of equipment including side-viewing duodenoscopes, forward-viewing gastroscopes or colonoscopes or even a double balloon enteroscope. A variety of specifically designed ERCP accessories is often also necessary to achieve cannulation, sphincterotomy and/or stent placement. Alternatives should be considered in patients with suspected biliary tract disease following bariatric surgery including the use of MRCP or percutaneous transhepatic cholangiography (PTC).

5 Endoscopic placement of intragastric balloons

This is undertaken in some countries as an alternative to bariatric surgery but has become less popular in recent years as bariatric surgery has developed. They have not been shown to be a convincing means of achieving major weight loss but offer prospects to non-morbidly obese patients not being considered for surgery, those unwilling to undergo an operation and those awaiting surgery.

Endoscopic insertion of intragastric balloons was introduced in 1985 by Garren-Edwards and Taylor. The balloons were round or oval, made of polyurethane, and filled with 300–600 cc of air or water. The first balloons were a source of numerous complications including migration, gastric perforation or ulceration. The criteria for balloon design were subsequently refined and the ‘ideal’ balloon should be effective as regards weight loss, smooth, radio-opaque, strong and water-filled, its volume should be adjustable and it should be easy to insert and remove. Progress has been made with the water-filled balloon (Bioenterics Intragastric Balloon, BIB, Inamed Health, Santa Barbara, USA); however, its volume is no longer adjustable.

5.1 Equipment and technique

The water-filled balloon is made of silicone, equipped with an antireflux valve, and is round so it is easily positioned after an endoscopic examination of the digestive tract under anaesthesia (Fig. 2). It is released into the stomach after filling with 500–600 mL of physiological saline containing methylene blue (Figs 3, 4). The IGB is released by traction, against the gastric cardia. The covering membrane frees itself gradually, releasing the balloon from its constraint.

image

Figure 2 Insertion of an intragastric balloon.

image

Figure 3 Intragastric balloon in position.

image

Figure 4 Release of a water-filled balloon (unfolding the covering membrane).

5.2 Indications

The use of an IGB depends on the patient’s history of obesity, associated co-morbidity and careful dietary assessment. Endocrinological and psychiatric consultations are not legally required but are recommended. Balloons can also be recommended for very obese patients waiting for surgery. In this setting, evidence of efficacy may influence the decision to operate because patients who have clearly lost weight over 6 months would potentially respond well to surgical treatment (the ‘IGB test’).

5.3 Contraindications

There is no consensus about contraindications (Box 1), but the presence of a large hiatus hernia, malignancy or active gastric or duodenal ulceration, may postpone the procedure or alter the approach. General anesthesia and intubation of the patient is advisable when balloons are inserted, because of the risk of aspiration. Given current knowledge of IGB, their use in adolescents is not recommended at present.

Box 1 Contraindications to use of intragastric balloons

• Severe/untreated psychiatric disease.
• Alcohol or drug addiction.
• Coagulopathy/anticoagulation.
• Pregnancy.
• Varices.
• Hiatal hernia >3 cm.
• Grade C or D esophagitis.

5.4 Monitoring

Patients should undergo clinical monitoring weekly or monthly after insertion of an IGB (laboratory tests in the event of vomiting, X-ray or ultrasound if fracture or migration is suspected), and regular consultations with a dietitian are an essential supplement of therapy for the duration of treatment. A mean weight loss of 10–12% over 6 months can be expected. According to the manufacturer’s recommendations, the IGB is left in position for 6 months and removed by puncture and suction of the physiological saline using a removable trocar mounted in a plastic catheter. Once flattened, the IGB is extracted using tripod forceps or a polypectomy snare (Figs 5, 6). As few perforations as possible should be made in the IGB because this may cause it to empty partially like a watering-can rose, forming pockets of fluid, which make it more difficult to remove.

image

Figure 5 Extraction of an IGB with grasping forceps after removal of its contents by suction.

image

Figure 6 Water-filled balloon after removal.

5.5 Complications

Expected immediate complications after insertion of an IGB are functional, such as vomiting (90% in the first week). This requires readmission to hospital in 5% of cases, because of hypokalemia and dehydration. Vomiting may last 1 week but can persist for more than 3 weeks in 20% of patients. Heartburn is present in up to 15% of patients, with or without esophagitis, and erosive gastritis an also occur. Colicky abdominal pain with diarrhea responds to antispasmodic and antidiarrheal agents. It is only rarely necessary (2–3%) to remove the IGB early because of persistent vomiting or pain. Spontaneous elimination of the balloon may occur in 2.5% of patients, usually without the patient’s awareness, despite the methylene blue. Cases of mechanical obstruction have been reported as a result of this.

5.6 Future developments

Air-filled balloons are still under investigation. Their insertion system is more rigid and removal more difficult because of the size of the valve. In contrast with water-filled balloons, the removal of air-filled balloons requires multiple puncture holes. Other devices including implantable intragastric prostheses, semi-stationary antral balloons and an implantable endoscopic duodenal-jejunal bypass sleeve are under development. In summary, the intragastric balloon is one of a number of methods available to doctors treating obesity and it should be offered only after the medical therapy has failed and a multidisciplinary medical decision has been taken, as in the case for surgery. There are no data on long-term efficacy, outcomes or quality of life and more studies are needed. They do not achieve the degree of durable weight loss that occurs following surgery but may be useful in selected patients, although more evidence of efficacy and safety are required.

Further Reading

ASGE standards of practice committee. Guideline. Role of endoscopy in the bariatric surgery patient. Gastroinest Endosc. 2008;68:1-9.

Coté GA, Edmundowicz SA. Emerging technology: endoluminal treatment of obesity. Gastrointest Endosc. 2009;70(5):991-999.

Feitoza AB, Baron TH. Endoscopy and ERCP in the setting of previous upper GI tract surgery. Part I: Reconstruction without alteration of pancreaticobiliary anatomy. Gastroinest Endosc. 2001;54:743-749.

Feitoza AB, Baron TH. Endoscopy and ERCP in the setting of previous upper GI tract surgery. Part II: postsurgical anatomy with alteration of the pancreaticobiliary tree. Gastrointest Endosc. 2002;55(1):75-79.

Sauerland S, Angrisani L, Belachew M, et al. European Association for Endoscopic Surgery. Obesity surgery: evidence-based guidelines of the European Association for Endoscopic Surgery (EAES). Surg Endosc. 2005;19:200-221.

Tsesmeli N, Coumaros D. Review of endoscopic devices for weight reduction: old and new balloons and implantable prostheses. Endoscopy. 2009;41(12):1082-1089.

Wright BE, Cass OW, Freeman ML. ERCP in patients with long-limb Roux-en-Y gastrojejunostomy and intact papilla. Gastrointest Endosc. 2002;56:225-232.

7.7 Polypectomy

Mouen Khashab, Jean Marc Canard, Anthony N. Kalloo

Summary

Introduction 198
1. Optical enhancement techniques 198
2. Equipment 199
3. Small polyp removal 199
4. Large pedunculated polyp removal 201
5. Large sessile polyp removal 202
6. Special clinical situations 204
7. Complications 205

Key Points

• Optical enhancement techniques, such as narrow-band imaging, FICE, or staining with 0.2% indigo carmine, may be used to predict polyp histology.
• Forceps polypectomy is best suited for diminutive polyps. Pedunculated polyps ≤5 mm and sessile polyps ≤7 mm may be resected with cold snaring.
• Polyps that exhibit the non-lifting sign and polyps that are ulcerated may harbor carcinoma. These polyps should be biopsied to exclude cancer prior to resection.
• Large sessile polyps resected in piecemeal fashion should be followed-up with repeat examination in 2–6 months to exclude residual or recurrent adenoma.
• Management of antithrombotic agents in the peri-endoscopic period depends on the bleeding risk from polypectomy and the thromboembolic risk associated with interruption of medications.
• Colonoscopy should be performed urgently in patients with active post-polypectomy hemorrhage.

Introduction

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide. The lifetime risk of developing CRC is 6%, with the majority of cancers occurring in people older than 50 years. CRC is believed to arise from adenomas through the adenoma to carcinoma sequence. Interruption of this progression through polypectomy is one of the most effective cancer prevention means in medicine. The National Polyp study showed that colonoscopy with removal of adenomas decreased the incidence of CRC by 76–90%. More recent studies showed that colonoscopy with polypectomy is associated with a relative reduction in CRC death of 65%. However, colonoscopy is imperfect and incident cancers after clearing colonoscopies continue to occur. Up to one-third of incident cancers are believed to be due to ineffective polypectomy. All endoscopists should therefore be familiar with effective and safe polypectomy techniques.

The aim of this chapter is to discuss techniques of removal of small polyps, large pedunculated polyps, and large sessile polyps. In addition, the chapter discusses the management of antithrombotic agents during the peri-endoscopic period, the treatment of malignant colorectal polyps, and the management of complications of polypectomy.

1 Optical enhancement techniques

Optical enhancement techniques, such as narrow-band imaging (NBI), chromoendoscopy (CE), autofluorescence (AF), Fuji Intelligent Chromo Endoscopy (FICE), and I-Scan, may be used to improve polyp detection and/or predict polyp histology in real time (Fig. 1) (see Ch. 6.2). The discussion of the former use is beyond the scope of this chapter. However, understanding the use of such techniques to predict polyp histology may assist in determining the need for polypectomy.

image

Figure 1 Sessile polyp. (A) This polyp in the transverse colon was identified as a sessile polyp using FICE and optical zoom. (B) Note the tubular pit patterns with no sign of adenocarcinoma.

NBI and CE are the most studied optical enhancing technologies. CE involves spraying of dye, and is cumbersome and time-consuming. NBI has been called digital chromoendoscopy, does not involve spraying of dye, and is an efficient means of predicting colon polyp histology. Table 1 depicts the endoscopic features that are predictive of adenomatous and hyperplastic histology when viewed by NBI. Experienced endoscopists can correctly predict adenomatous and hyperplastic histology of diminutive polyps (≤5 mm) in 90–95% of cases. NBI may, thus, identify small distal hyperplastic polyps that need not be resected (or resected and discarded). All proximal hyperplastic polyps, however, should be resected as they may represent serrated adenomas, which are now recognized as precancerous lesions.

Table 1 Endoscopic features predictive of polyp histology when viewed by NBI

Adenomatous polyps Hyperplastic polyps
Short thick blood vessels
Overall brown color
Tubular or oval pits
Central brown depression

Thin blood vessels crossing polyp surface and not surrounding pits
Bland, featureless appearance
Pattern of black dots surrounded by white

Another potential use of optical enhancement techniques is examination of polypectomy sites to assess the adequacy of polypectomy and the presence of residual or recurrent adenomatous tissue at the index or follow-up colonoscopic examinations, respectively.

2 Equipment

Box 1 Equipment

• Polypectomy snaresa.
• Cold and hot biopsy forceps.
• Tripod grasper forceps.
• Injection needle.
• Endoscopic clips.
• Detachable loops.
• Polyp retrieval ‘Roth’ nets (Fig. 2).
• Polyp trap (Fig. 2).
• Tattoo (Sterile carbon suspension rather than India Ink).
• Epinephrine.
image image

Figure 2 Polyp retrieval devices. (A) Polyp retrieval net (Roth). (B) A polyp trap is useful for small polyps which can be suctioned and then captured in the trap.

aSnares come in a variety of shapes and sizes. We usually use hexagonal snares, as they can be half opened to remove small polyps, and fully opened to remove large polyps.

3 Small polyp removal

3.1 General concepts

• Small polyps have a maximum diameter of <10 mm and diminutive polyps have a maximum diameter of ≤5 mm.
• Most colon polyps are diminutive (80%) or small (90%).
• The optimal technique for resection of small polyps has not been established.
• The benefit of removal of all diminutive adenomas is not known.
• Most polypectomy complications result from small polyp removal because of their prevalence.
• Most polypectomy complications are electrocautery-related.
• Electrocautery is not needed in the resection of many small polyps.

3.2 Cold biopsy forceps

• Cold forceps are appropriate for the resection of smallest polyps (1–3 mm in size).
• Hot forceps are best suited for resection of diminutive flat polyps that are harder to grasp with a snare.
• Resection of larger polyps using a biopsy forceps in piecemeal fashion is inefficient and may result in residual adenomatous tissue.

image Clinical Tips

• Polyps >3 mm are usually resected in piecemeal fashion when forceps are used for resection. The endoscopic field may become bloodied, which may obscure the margins of the residual polyp. It is better to use hot biopsy forceps.
• Cold forceps are not associated with increased complication risks and can be used safely in anticoagulated patients and patients on anti-platelet agents.

3.3 Hot biopsy forceps

• The tip of the polyp should be grasped and tented away from the colonic wall to create a pseudo-stalk. Lumen should be first deflated and electrocautery is then applied. Since the electric current density concentrates at the narrowest point, the pseudo-stalk is cauterized.
• Hot forceps are also best suited for resection of diminutive polyps. Resection of larger polyps with hot forceps involves piecemeal resection and risks incomplete polyp removal.
• Hot forceps are associated with an increased risk of delayed post-polypectomy bleeding and transmural thermal injury.
• Hot forceps biopsies are associated with a 8–16% risk of residual polyp.

image Clinical Tips

• The right colon is particularly susceptible to transmural injury and perforation. Great care must be taken when using hot biopsies in the right colon.
• The American Society for Gastrointestinal Endoscopy (ASGE) recommends that hot forceps should be used only for polyps ≤5 mm.

3.4 Cold snare

• The V of the open snare should be positioned at the point the endoscopist wants the snare to close. This is usually at the junction between the polyp and the adjacent normal tissue (Figs 3, 4). Be careful to check that the colon wall is not caught in the snare before cutting (Fig. 5).
• In general, snaring techniques are more effective than forceps techniques for efficient and complete eradication of polyps.
• Cold snares are effective for resecting sessile polyps up to 7 mm in size and pedunculated polyps up to 5 mm in size.
image

Figure 3 How to place a diathermy snare around the stalk of the polyp. (A) Position the polyp in the 6 o’clock position. Open the snare beyond the polyp and then place it over polyp. (B) Push the snare forward slightly to advance it onto the stalk of the polyp. (C) Once it is around the stalk, close the snare slowly, withdrawing the polyp slightly.

image

Figure 4 An alternative technique is to place the snare over the front of the polyp and then close the snare behind the polyp. This technique is used when the polyp is difficult to snare using the classic technique.

image

Figure 5 Pitfalls in polypectomy. (A) Be careful to check that the colon wall is not caught in the snare before cutting. (B) This can be avoided by first advancing the snare over the polyp under direct vision before closing.

image Clinical Tips

• Hot snaring should be used for resection of larger (>5 mm) pedunculated polyps because their stalk may enclose large blood vessels; electrocautery coagulates blood vessels and helps avoid bleeding complications.
• There is no need to lift or tent the polyp away from the colonic wall when using cold snare technique. Avoiding tenting may help keep the resected polyp in the endoscopic field.

image Clinical Tip

Some authorities recommend resecting 1–2 mm rim of normal tissue around the polyp edge along with polyp to ensure complete resection. This should be avoided when using hot snaring because it increases the size of the cautery burn.

3.5 Hot snare

• Different types of currents may be used for hot snare polypectomies (Table 2). There is currently no consensus for the optimal type of current that should be used. The intensity of the heat delivered per mm of contact depends on the contact area (Fig. 6).
• We usually use endo-cut mode as this setting has a low risk of bleeding while having sufficient cutting current to resect a polyp.
• The ensnared polyp should be lifted away from the colonic wall and the lumen deflated prior to the application of electrocautery to minimize the risk of transmural injury.
• Pedunculated polyps >5 mm are best resected with a hot snare.

Table 2 Types of currents used for polypectomies

Current type Early bleeding risk Delayed bleeding risk
Coagulation ↓ ↑
Cutting ↑ ↓
Blended ↑ ↓

The type of current affects the risk of early or late bleeding. Thus coagulation is associated with an increased risk of delayed bleeding, while using a cutting current is associated with a decreased risk of delayed bleeding but an increased risk of early bleeding.

image

Figure 6 The intensity of the heat delivered per millimeter of contact depends on the contact area.

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Small bowel endoscopy Introduction to endoscopy Diagnostic upper endoscopy Preparation for endoscopy Diagnostic colonoscopy Endosonography