**4. Endoscopic methods for examination of the small intestine**

Although numerous advances have recently been made in endoscopy for diagnosis and treatment of gastrointestinal diseases, they have taken little account of the small bowel, as access by endoscopy is often difficult. The most recent discoveries—capsule endoscopy, double-balloon enteroscopy, and spiral enteroscopy—have improved our ability to examine the small bowel. Capsule endoscopy has given rise to a new challenge, namely, how to diagnose and treat the lesions found. In this section, we describe the different methods used to perform enteroscopy, from the earliest to the most recent.

Fig. 3. Jejunal stenosis in a patient with Crohn disease. Geographic ulcers at the level of the stenosis

*Push Enteroscopy.* For several years, push enteroscopy has been the most widely used and effective procedure for direct examination of the intestinal mucosa. It comprises a 200-cm– long endoscope and a 2.8-mm working channel. One of its limitations is that is only allows us to visualize the proximal and medial jejunum, leaving much of the small intestine unexplored. In order to progress, smooth and intermittent aspiration maneuvers are necessary to avoid suction artifacts on the mucosa. Minimal insufflation should be applied

Efficacy of the Pediatric Colonoscope Used as a Push Enteroscope 233

Insertion depth is 262±57 cm and the examination takes an average of 35 minutes. This endoscopic modality also allows the use of therapeutics, including biopsy, hemostatic agents, and polypectomy (working channel of 2.8 mm). Only minor complications of sore throat and minimal mucosal trauma have been reported to date and no perforations. Some studies compare this approach with double-balloon enteroscopy and show that the latter has a higher diagnostic yield. In addition, this technique requires 2 endoscopists, one to turn the overtube and the other to push the endoscope. It is important to remember that the overtube contains latex—as do the balloons in balloon-assisted enteroscopy—and therefore

*Intraoperative enteroscopy.* Intraoperative enteroscopy by insertion of an endoscope through 1 or more enterotomies to examine the whole small bowel has a high diagnostic yield, identifying lesions in 70-100% of patients. The technique commences once the surgeon has performed a laparotomy to gain access to the small bowel. Once the small bowel is exposed, 2 or more enterotomies are made and the colonoscope is inserted with the surgeon's help. Intraoperative enteroscopy makes it possible to examine the whole small bowel, although the assistance of a surgeon is necessary. It is limited by its high morbidity (intestinal wall hematoma, mesenteric hemorrhage, prolonged ileus, intestinal ischemia, and perforation) and is therefore reserved for patients with persistent bleeding and high transfusional requirements in whom diagnosis cannot be established by other means (Figure 4). A variation of the technique involves oral insertion of the enteroscope during surgery, which makes it possible to visualize 93% of the ileum and establish a diagnosis in almost 60% of cases. Its drawback is the considerable operative morbidity in a relatively high proportion of

represents an added risk in patients with latex allergy.

cases (serosal tear or mesenteric vein avulsion).

Fig. 4. Ileal ulcer (arrow) with completely denuded submucosa

**5. Push enteroscopy performed using a pediatric colonoscope** 

Capsule endoscopy can be used to examine the small bowel for the indications presented above. However, it is exclusively a diagnostic technique; therapy must be administered

due to the risk of overdistension and greater formation of loops. The technique identifies fewer lesions than upper and lower endoscopy, as the small bowel is less commonly affected by disease (Figure 3); therefore, the indications should be carefully selected in order to achieve diagnostic yield, and more importantly, therapeutic yield. The mucosa is usually more visible on withdrawal, during which the distance reached relative to the angle of Treitz is better appreciated.

#### *Balloon-assisted enteroscopy.*

a. *Double-balloon enteroscopy.* Double-balloon enteroscopy represents a huge advance. In theory, the whole small bowel can be examined, biopsies taken, and treatment administered, or, if this is not possible, the lesion can be marked. The technique comprises a thin enteroscope with a special flexible overtube, at the distal end of which 2 balloons are attached. These balloons are inflated and deflated by continuous pressure control, and both instruments can be pushed forward or withdrawn. The technique makes it possible to reach more distal sections of the small bowel, although it rarely manages to reach the terminal ileum; therefore, enteroscopy requires the combination of the antegrade and retrograde approaches for an examination of the whole bowel. Double-balloon enteroscopy is considered a safe and well-tolerated technique for the diagnosis and treatment of small bowel diseases, with a working channel ranging in size from 2.2 mm to 2.8 mm.

The technique is contraindicated in patients who have recently undergone digestive surgery and in those with perforated viscus, life-threatening hemodynamic instability, and severe respiratory insufficiency. The most common complications are cardiopulmonary abnormalities, bacteremia, hemorrhage, pancreatitis, dissected aortic aneurysm, volvulus, and incarcerated inguinal hernia. At present, double-balloon enteroscopy is used mainly to administer therapy after capsule endoscopy, except when it is contraindicated.

b. *Single-balloon enteroscopy.* Single-balloon enteroscopy is the latest balloon-assisted endoscopic technique for the evaluation and management of small bowel disorders. It involves inserting a balloon catheter through the working channel of a colonoscope and moving the endoscope progressively along the small intestine by inflating and deflating the balloon. This technique has proven safe and effective, and in some cases (up to 25%) has made it possible to perform a complete enteroscopy. The earliest versions involved an enteroscope with a 2.8-mm working channel; however, more recently, a pediatric colonoscope with a wider working channel (3.2 mm) has been used, with no reduction in insertion depth. Compared with double-balloon enteroscopy, this technique presents fewer complications, enables a complete enteroscopy to be performed in a lower percentage of patients, and has a similar or wider working channel.

*Spiral enteroscopy.* Spiral enteroscopy allows for advancement and withdrawal of the enteroscope through the small bowel by using clockwise and counterclockwise movements, respectively. The distal end of the overtube is positioned 25 cm from the tip of the enteroscope and locked into place. The system is then advanced to the ligament of Treitz with gentle rotation. The collar is subsequently unlocked, and the enteroscope is advanced past the ligament of Treitz. The overtube is then advanced using clockwise rotation until pleating of the small bowel no longer occurs over the enteroscope. The enteroscope is then unlocked and advanced to facilitate further advancement into the small bowel. In order to ease withdrawal of the enteroscope, the overtube is rotated in a counterclockwise direction.

due to the risk of overdistension and greater formation of loops. The technique identifies fewer lesions than upper and lower endoscopy, as the small bowel is less commonly affected by disease (Figure 3); therefore, the indications should be carefully selected in order to achieve diagnostic yield, and more importantly, therapeutic yield. The mucosa is usually more visible on withdrawal, during which the distance reached relative to the angle of

a. *Double-balloon enteroscopy.* Double-balloon enteroscopy represents a huge advance. In theory, the whole small bowel can be examined, biopsies taken, and treatment administered, or, if this is not possible, the lesion can be marked. The technique comprises a thin enteroscope with a special flexible overtube, at the distal end of which 2 balloons are attached. These balloons are inflated and deflated by continuous pressure control, and both instruments can be pushed forward or withdrawn. The technique makes it possible to reach more distal sections of the small bowel, although it rarely manages to reach the terminal ileum; therefore, enteroscopy requires the combination of the antegrade and retrograde approaches for an examination of the whole bowel. Double-balloon enteroscopy is considered a safe and well-tolerated technique for the diagnosis and treatment of small bowel diseases, with a working channel ranging in

The technique is contraindicated in patients who have recently undergone digestive surgery and in those with perforated viscus, life-threatening hemodynamic instability, and severe respiratory insufficiency. The most common complications are cardiopulmonary abnormalities, bacteremia, hemorrhage, pancreatitis, dissected aortic aneurysm, volvulus, and incarcerated inguinal hernia. At present, double-balloon enteroscopy is used mainly to administer therapy after capsule endoscopy, except when

b. *Single-balloon enteroscopy.* Single-balloon enteroscopy is the latest balloon-assisted endoscopic technique for the evaluation and management of small bowel disorders. It involves inserting a balloon catheter through the working channel of a colonoscope and moving the endoscope progressively along the small intestine by inflating and deflating the balloon. This technique has proven safe and effective, and in some cases (up to 25%) has made it possible to perform a complete enteroscopy. The earliest versions involved an enteroscope with a 2.8-mm working channel; however, more recently, a pediatric colonoscope with a wider working channel (3.2 mm) has been used, with no reduction in insertion depth. Compared with double-balloon enteroscopy, this technique presents fewer complications, enables a complete enteroscopy to be performed in a lower

*Spiral enteroscopy.* Spiral enteroscopy allows for advancement and withdrawal of the enteroscope through the small bowel by using clockwise and counterclockwise movements, respectively. The distal end of the overtube is positioned 25 cm from the tip of the enteroscope and locked into place. The system is then advanced to the ligament of Treitz with gentle rotation. The collar is subsequently unlocked, and the enteroscope is advanced past the ligament of Treitz. The overtube is then advanced using clockwise rotation until pleating of the small bowel no longer occurs over the enteroscope. The enteroscope is then unlocked and advanced to facilitate further advancement into the small bowel. In order to ease withdrawal of the enteroscope, the overtube is rotated in a counterclockwise direction.

percentage of patients, and has a similar or wider working channel.

Treitz is better appreciated. *Balloon-assisted enteroscopy.* 

size from 2.2 mm to 2.8 mm.

it is contraindicated.

Insertion depth is 262±57 cm and the examination takes an average of 35 minutes. This endoscopic modality also allows the use of therapeutics, including biopsy, hemostatic agents, and polypectomy (working channel of 2.8 mm). Only minor complications of sore throat and minimal mucosal trauma have been reported to date and no perforations. Some studies compare this approach with double-balloon enteroscopy and show that the latter has a higher diagnostic yield. In addition, this technique requires 2 endoscopists, one to turn the overtube and the other to push the endoscope. It is important to remember that the overtube contains latex—as do the balloons in balloon-assisted enteroscopy—and therefore represents an added risk in patients with latex allergy.

*Intraoperative enteroscopy.* Intraoperative enteroscopy by insertion of an endoscope through 1 or more enterotomies to examine the whole small bowel has a high diagnostic yield, identifying lesions in 70-100% of patients. The technique commences once the surgeon has performed a laparotomy to gain access to the small bowel. Once the small bowel is exposed, 2 or more enterotomies are made and the colonoscope is inserted with the surgeon's help. Intraoperative enteroscopy makes it possible to examine the whole small bowel, although the assistance of a surgeon is necessary. It is limited by its high morbidity (intestinal wall hematoma, mesenteric hemorrhage, prolonged ileus, intestinal ischemia, and perforation) and is therefore reserved for patients with persistent bleeding and high transfusional requirements in whom diagnosis cannot be established by other means (Figure 4). A variation of the technique involves oral insertion of the enteroscope during surgery, which makes it possible to visualize 93% of the ileum and establish a diagnosis in almost 60% of cases. Its drawback is the considerable operative morbidity in a relatively high proportion of cases (serosal tear or mesenteric vein avulsion).

Fig. 4. Ileal ulcer (arrow) with completely denuded submucosa
