Single Balloon Enteroscopy: Is It Feasible?

Equipment 

The dedicated SIF Q260 enteroscope (Olympus Optical Co., Tokyo, Japan) has a high-resolution CCD (Q image; Olympus), a 200-cm working length, a 9.2-mm outer diameter, and a 2.8-mm working channel (Fig. 1). The flexible silicon sliding tube (ST-SB1; Olympus) is 140 cm in length, and has an 11.0-mm inner diameter and 13.2-mm outer diameter with a soft balloon at the tip of the tube. A pressure-controlled pump system (OBCU; Olympus, pressure setting range: −6.0 to + 6.0 KPa) controls balloon inflation/deflation through a narrow tube implanted into the wall of the sliding tube. The SIF-Q260, like most endoscopes from Olympus, is usually attached to an Olympus EVIS 240, 260, and SL systems, which are regular video processors. Furthermore, this scope can be combined with a Narrow Band Image (NBI) system that may expand its diagnostic value.8 Fluoroscopy should be used when the sliding tube is inserted and the small intestine is shortened, or when insertion of the endoscope is difficult due to loop formation, intestinal adhesions, etc.

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Figure 1. Single balloon enteroscopy system. (Color version of figure is available at www.techgiendoscopy.com.)

Indications 

The indications for SBE examination included all patients who were evaluated for small-bowel pathology, and written informed consent was obtained from all participants. The patients were investigated for obscure gastrointestinal bleeding, Crohn’s disease, chronic abdominal pain, chronic diarrhea, and suspected small-bowel tumors. All of the patients had undergone at least one EGD or colonoscopy.

Preparation and Sedation 

After an overnight fast, the patients underwent small-bowel cleansing at least 4 hours before the procedure with a polyethylene glycol lavage solution (Niflec; Ajinomoto Pharma Co., Tokyo, Japan) for retrograde examination. In the endoscopy room, all patients received the appropriate cardiorespiratory monitoring (continuous electrocardiogram, heart rate, oxygen saturation monitor, and intermittent blood pressure measurement), and were given propofol (3 mg/kg) and pentazosine hydrochloride (15 mg) for conscious sedation.

SBE Insertion Method 

The insertion method for SBE is similar to that for DBE. The main difference between SBE and DBE is the method of holding the small intestine using the endoscope during insertion of the sliding tube (Fig. 2). After the endoscope is inserted maximally, the tip of the endoscope is bent 180° through its maximal up-angle or down-angle. Using this hook shape of the scope instead of the inflated balloon on the tip in DBE, the endoscope can hold the small intestine in the same position, and then the sliding tube can be inserted further without stretching the intestine. When the tip of the sliding tube arrives at the bent hook, the balloon is then inflated to grip the intestine. After returning the tip of the endoscope to the neutral position to avoid mucosal injury, both the scope and the sliding tube are simultaneously withdrawn, thus shortening the intestine. By repeating these maneuvers, the endoscope can be inserted further into the deep intestine.

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Figure 2. Insertion theory of SBE: (1) withdraw endoscopy and sliding tube, (2) insert endoscopy, (3) bend the tip of endoscopy, (4) deflate balloon, (5) insert sliding tube, (6) inflate balloon, (7) neutral position of the tip, and (8) withdraw endoscopy and sliding tube. (Color version of figure is available at www.techgiendoscopy.com.)

Endoscopist and Assistant 

The endoscopist who manipulates the SBE requires sufficient skill to perform a colonoscopy by the one-man method. In addition to the endoscopist, another doctor assists by inserting the sliding tube, and one physician administers the conscious sedation.

Route Selection and Patient Position 

Except for those cases where the route was specifically selected, all patients received SBE from both routes. Typically, SBE from the oral approach was selected first, and then the examination from the anal route was performed on the same day as soon as the patient recovered from the first sedation. During the SBE examination, the patient was placed in the prone position for the oral route to avoid aspiration pneumonia. For the anal route, the patient was placed in a left lateral decubitus position during recto-sigmoid insertion, and then switched to a supine position after the sigmoid-descending junction was passed.

Concrete Insertion 

Before passing the scope through the sliding tube, 10 mL of water is injected into the sliding tube. Since the inner lumen of the sliding tube is treated with a hydrophilic coating, the endoscope can move smoothly in the sliding tube after moistening. For the oral route, the scope is inserted into the stomach initially. Next, the sliding tube is inserted into the stomach. The scope is inserted further and should reach deeper than the second portion of the duodenum. After stretching the region from the second portion of duodenum to the stomach, the sliding tube is passed through the pylorus ring. Fluoroscopy is a valuable aid during this maneuver. It is recommended that the balloon be positioned over the papillae of Vater at first inflation to avoid acute pancreatitis.9 After the sliding tube passes Treitz’s ligament, the endoscopist may repeat the shortening procedure to the limit of insertion. In the small intestine, the shape of the scope causes a clockwise or anticlockwise torque that depends on the patient’s proportions.

For the anal route, the scope is so flexible that insertion from the anal to ileocecal valve is more difficult than in conventional colonoscopy. The operators should use fluoroscopy properly and use care with the balloon in the colon to prevent the colon from being twisted. After passing the ileocecal valve, the procedure is the same as for the oral route from the small intestine. We defined the deep small intestine as the point when the proximal end of the sliding tube was inserted maximally. During oral insertion, we placed a clip at the deepest point and judged the total enteroscopy to be complete when the clip could be observed by anal insertion.

Recently, we developed a novel SBE system and its insertion technique for examination of the small intestine.

Is SBE Feasible? 

With respect to the feasibility of SBE, which is the primary question, the rate of complete enteroscopy was only 29% (6/21). It has been reported that complete enteroscopy was achieved with DBE in 50% to 86% of those patients without adhesions or prior surgery.10, 11, 12 Although we continue to improve our skill in using SBE, the balloon on the DBE scope may be more helpful than the hook shape of the SBE scope, especially deep in the intestine or when it is twisted. A comparative study between SBE and DBE is necessary to evaluate whether the ease of insertion and the ability to inspect the small bowel are comparable. With respect to safety during insertion, we experienced a mucosal tear at a longitudinal ulcer scar caused by the tip of the scope in one patient with Crohn’s disease. The operator should pay close attention when using the hook tip of the endoscope near adhesions or narrowings of the small intestine. We conclude that an enteroscope with even a single balloon can safely and effectively inspect the deep small intestine. Therefore, SBE is a feasible diagnostic and therapeutic tool in the small intestine in addition to DBE.