Dra. Ana Echarri Piudo
Complejo Hospitalario Universitario de Ferrol
Dra. Begoña González Suárez
Hospital Universitari Clínic. Barcelona
Balloon enteroscopy in its two forms, double-balloon (DBE) or single-balloon (SBE) enteroscopy, is an endoscopic procedure that enables the directed and controlled examination of the entire small intestine (SI) with the option of obtaining endoscopic and histologic diagnoses (by taking biopsies) and providing treatment.
It is a endoscopic technique that complements the capsule endoscopy (CE) to enable biopsies and therapy to be performed in areas where we would not have access using conventional endoscopes (Table I)1,2.
The DBE system has a video enteroscope with a working length of 200 cm, with a 145-cm overtube that is mounted on top. Both the tube and overtube have latex balloons attached at the distal end and connected to a pump that monitors the inflation and deflation pressure (45 mmHg), with an audiovisual safety system in case of overpressure.
There are two enteroscopes with different external diameter and working channel measurements. The EN-450P5 enteroscope (Fujinon®) for diagnostic use, with an external diameter of 8.5 mm (enteroscope) or 12.2 mm (with overtube) and a working channel of 2.2 mm and the enteroscope for therapeutic use (EN‑450T5, Fujinon), with an external diameter of 9.4 mm (enteroscope) or 13.2 mm (with overtube) and a biopsy channel of 2.8 mm. The overtube balloon is already installed while the endoscope balloon must be placed manually. The proximal end of the overtube has two connections: one corresponds to the interior light and the other connects the distal balloon to the manometry equipment (Fig. 1). Enteroscopes are connected to a video processor with magnification and the option of chromoendoscopy.
The auxiliary material used during the process depends on the working channel of each enteroscope. Certain instruments, such as dilators or prosthesis pushers, cannot be used through a 2.2-mm channel, while the working channel of the therapeutic enteroscope enables the use of instruments used in conventional colonoscopy. Frequent physiological serum instillation between the overtube and the enteroscope enables sliding. The use of a silicone spray is advised for applying the accessory instruments prior to introduction through the working channel3-5.
The enteroscope is introduced by anterograde (oral) or retrograde (anorectal) techniques. With both balloons collapsed, the endoscope is advanced until maximum reach is achieved, which can be the second part of the duodenum (balloon inflation is recommended once the papillary area is passed over to avoid any potential pancreatitis) or the descending colon, respectively: at this time, the endoscope balloon is insufflated and the overtube is slid up to the tip of the enteroscope6,7.
1. Insertion of the enteroscope.
2. Inflation of the enteroscope balloon.
3. Deflation of the overtube balloon.
4. Insertion of the overtube up to the tip of the enteroscope.
5. Inflation of the overtube balloon.
6. Removal of the set (tube, overtube, with both inflated balloons) as a unit in order to fold the intestine over the overtube. Deflation of the enteroscope balloon.
7. Repeating movements 1-6 (average of 12 times/examination: duration > 1 hour)3,4.
The manoeuvre described above helps to eliminate loop formation, being able to fold the intestine like an “accordion” in sections of approximately 40-cm. Most of the time it is necessary to do both anterograde and retrograde approaches at different times in order to achieve a full examination of the small intestine. In some cases, it is best to use fluoroscopy support to assess the enteroscope’s position.
The published percentages of success in full SI examination range between 40%–80%, and are limited in patients with high body mass index in which mesenteric fat reduces the capacity of the intestinal fold, as well as in subjects with previous surgeries. It is important to note that it is not always necessary to examine the entire SI: the objective of the test is to reach the lesion viewed previously in other tests (generally capsule endoscopy or radiologic technique) in order to take biopsies or perform timely treatments8,9.
The decision to perform anterograde or retrograde DBE is determined by the location of the lesion in previous diagnostic tests. If the lesion is located in the 2/3 proximal segments of the SI, the enteroscopy uses the anterograde approach, while if the lesion are located in the in third inferior segment of the SI, the anal route is the choice for performing the test10.
To perform oral DBE, fasting 12 hours prior to the test is advised, and if using an anal approach, the intestinal cleaning preparation is similar to that of the colonoscopy.
A single-balloon enteroscope (Olympus® SIF Q 180) is a video enteroscope with a length of 200 cm, an external diameter of 9.2 mm and a working channel of 2.8 mm; an overtube is used over the endoscope that measures 140 cm, with a hydrophilic balloon made of silicone located at the end, which connects to the balloon controller unit (Fig. 2). The controller unit contains a manometric device that controls the balloon pressures and is equipped with audible alarms that signal when there is high insufflation or pressure, which automatically deflates the balloon and decreases the risk of intestinal lesion11.
For the insertion technique, generally a series of repetitive movements are used, following this sequence:
- Insertion of the enteroscope.
- Folding or anchoring the tip of the equipment.
- Deflating the overtube balloon.
- Sliding the overtube over the enteroscope.
- Insufflating the balloon again.
- Removing the enteroscope and overtube set.
Most of the time, a full SI examination requires a anterograde and retrograde combination. The advantage of an enteroscope with a single-balloon versus a DBE is the reduced examination time, although the total examination percentage in most of the series is higher for DBE (Fig. 3)12.
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