Balloon-assisted enteroscopy

Introduction: Double-balloon enteroscopy (DBE) was the first method to be developed that allowed deep advancement into the small bowel for therapy. Other devices using a single balloon and balloon-through-scope have followed. Endoscopy of the small bowel is challenging because of its length (600–800 cm in adults), small luminal diameter, and looped anatomy within the abdominal cavity. This makes for a labor-intensive endoscopic procedure and a steep learning curve to accomplish complete enteroscopy. Previous abdominal surgery with adhesions that fix the bowel and altered anatomy add to the challenge. Peristalsis, lesion positioning, and limited tool options make therapy difficult. Complications include perforation, pancreatitis (predominantly from the upper approach), and bleeding. Minor complications include sore throat and abdominal distension. Observing some do’s and don’ts and applying a few tips and tricks can improve efficiency and success.

Dos and don’ts

1. Have a strong indication. This requires review of the clinical history, capsule endoscopy video, radiologic imaging, and surgery reports (if relevant) prior to procedure. Experience in capsule reading is important in decision making with regard to lesion interpretation and approach to lesion (upper vs. lower approach). Don’t go in blind.
2. Proper training. Attend hands-on courses and observe live courses and/or a skilled balloon-assisted enteroscopist. In the original U.S. experience with DBE, it was not until 50 procedures had been performed that procedural time decreased [1]. Complete enteroscopy is not reliably achieved until after 150 procedures [2].
3. Choose the balloon-assisted system that works for you. The double-balloon, single-balloon, and balloon-through-scope systems all allow deeper small-bowel advancement than push enteroscopy and have similar diagnostic yields. The double-balloon system has the advantage of two balloons (tip of scope and overtube) that decrease slippage and maximize bowel pleating and depth of insertion. Latex balloons and longer set-up time are disadvantages. The single-balloon system has a sole, non-latex balloon on the overtube and relies on mucosal suction or tip flexion to hold the position, which creates more slippage and may limit depth of insertion. The balloon-through-scope is the newest device and experience with this device is limited. Pick a system that is compatible with your unit.
4. Dedicated team. The equipment and set-up (enteroscope, overtube, air pump/CO2, tools) for balloon-assisted enteroscopy is unique. Time and money will be wasted with unskilled staff and lead to endoscopist frustration.
5. Balloon-assisted enteroscopy is a long procedure and requires deep sedation and or anesthesia assistance. With the upper approach, airway management can be challenging.
6. Allow sufficient time. When a lesion is found deep in the small bowel on capsule endoscopy or an imaging study, the goal is to reach the lesion and perform the planned therapy. Don’t start in a 45-minute time slot when it might take up to 2 hours to reach and treat a lesion deep in the small bowel. The procedure should only be stopped if a lesion cannot technically be reached despite all maneuvers.

Tips and tricks

1. Unraveling and examining bowel. Much like a surgeon who externally “runs” the small bowel, the goal to successful enteroscopy is to first unravel a segment of small bowel by minimal insufflation and jiggling and then advance 1:1 without bowing. There is vigorous to-and-fro peristalsis in the small bowel that can work for you (antegrade peristalsis) or against you (retrograde peristalsis). With the upper approach, peristalsis helps with “fro” movement, so ride the wave when you can.
2. Managing the overtube. The overtube is important in bowel reduction and straightening the next segment for forward intubation. After deflating the overtube balloon, wait until there is “to” movement (bowel contraction toward you on screen) and then advance the overtube. This facilitates bowel pleating back on the overtube. When performing reductions, pull back on the overtube in the direction that allows the least bowel slippage and until there is gentle resistance. The goal is to tightly pleat the examined bowel back on the overtube.
3. Suction, suction, suction. Minimal air insufflation is desirable and allows efficient bowel pleating and deeper intubation. If CO2 is available, USE IT. Small water flushes keep the lumen open and promote peristalsis for riding the wave.
4. What to do when stuck. This usually occurs at sharp angulations with repeated slippage at the same spot and no forward advancement. A double advance (enteroscope and overtube advanced twice without an intervening reduction), use of a stiffener, gentle abdominal pressure, or changing patient position may help with advancement. Repeated slippage despite all measures usually means there is fixed bowel or maximal pleating. Do not waste time going back and forth, over and over, in the same place.
5. Lower approach. Can be challenging with a long, looped colon, large cecum, retroflexed ileocecal (IC) valve, or fixed terminal ileum. Position the IC valve at 9 o’clock, decompress cecum, and directly enter the IC valve. May need to finesse your way around the angulated terminal ileum before free forward advancement is possible. Abdominal pressure or a stiffener may help when forward advancement into the terminal ileum leads to retroflexion in the cecum.
6. Inform team of planned therapy so correct tools are laid out (correct length and diameter for balloon-assisted system). Overtube balloon inflation helps maintain a polyp in a stable position for safe removal. Use glucagon when vigorous peristalsis impedes therapy. Lubricate tools before advancement into the endoscope channel as it is hard to pass them deep in the small bowel when in a torqued position. Use lift injection with sessile polyp removal. Remove large polyps (particularly hamartomas) at stalk. There is an increased bleeding risk with piecemeal polyp removal. Injection of dilute epinephrine in a large polyp head and marking the stalk with dye may allow better polyp visualization for resection. Clip polypectomy sites to prevent bleeding. Accurate tattoo placement is crucial to mark lesions (tumor, ulcer, stenosis) for surgical resection.
7. Bleeding therapy. Use a cap and glucagon when vigorous peristalsis impedes therapy. Use APC for non-bleeding angioectasias, and bipolar probe or clip for streaming lesions. Exercise caution with epinephrine use in small bowel because of the risk of ischemia. Customize thermal settings for small bowel (jejunum is thicker-walled than the ileum). Continuing anticoagulation helps localize streaming lesions, only found when actively bleeding. Mark and clip brisk bleeding sites deep in the small bowel, to allow site identification should interventional radiology or surgery be warranted. There is a 30%–60% re-bleeding risk with vascular bleeding, particularly with medical co-morbidities (end stage renal disease [ESRD] on dialysis, portal HTN, chronic obstructive pulmonary disease [COPD]). If there is recurrent bleeding despite thermal therapy, do not repetitively cauterize. Consider medical or conservative therapy.
8. Stricture dilation. Most literature concerns Crohn/nonsteroidal anti-inflammatory drug (NSAID) strictures. Safe with short (<5 cm), straight, fibrotic, non-ulcerated strictures [3]. Perforation risk increases with dilation size. Think twice about dilating a stricture if asymptomatic and no bowel dilation on imaging study.

References

1. Mehdizadeh S, Ross A, Gerson L et al. What is the learning curve associated with double-balloon enteroscopy? Technical details and early experience in 6 U.S. tertiary care centers. Gastrointest Endosc 2006; 64: 740–750
2. Gross SA, Stark ME. Initial experience with double-balloon enteroscopy at a U.S. center. Gastrointest Endosc 2008; 67: 890–897
3. Arulanandan A, Dulai PS, Singh S et al. Systematic review: Safety of balloon assisted enteroscopy in Crohn’s disease. World J Gastroenterol 2016; 22: 8999–9011