The small bowel is approximately 20 feet in length and, until recently, was a relatively inaccessible part of the gastrointestinal tract. Although the advent of the wireless video capsule endoscopy system allowed lesions and abnormalities in the small bowel to be visualized, these could not be biopsied or treated. Balloon assisted enteroscopy was developed to provide non-surgical small bowel therapy. Through this new technique, it is now possible to biopsy tissue, dilate strictures, remove polyps, and stop bleeding from the small bowel. In some instances, therapy with a balloon assisted scope may allow patients to avoid surgical intervention on the small bowel.
The balloon system consists of a 200 cm endoscope and an overtube. There are one or two inflatable balloons attached to the scope and/or overtube. The technique allows the scope to advance through the length of the small bowel via the process of inflating and deflating the balloon(s), which grip the walls of the small intestine. With a series of ‘reductions’ the process pleats the small bowel over the overtube, like a curtain over a rod, and advances the scope. Accessories such as biopsy forceps, dilating devices, and cautery probes can be passed through channels in the scope in order to treat abnormal findings in the small intestine.
Balloon assisted enteroscopy can be performed in an outpatient or inpatient setting and may require several hours, depending on the therapy required. It is often performed with general anesthesia although some patients may require only moderate sedation. Fluoroscopy, or the use of X-ray, is frequently employed during the procedure. Most procedures are performed through the mouth (antegrade) although the retrograde approach, through the rectum, may allow better access to lesions in the lower part of the small bowel.
The risks of the procedure are similar to those for colonoscopy and upper endoscopy (EGD) and include bleeding, perforation, and complications of sedation. Unique to balloon enteroscopy are the risks of ileus (transient slowing of the bowel) and pancreatitis, which occur in less than one percent of procedures.
The indications for balloon assisted enteroscopy include the need for treatment of small intestinal lesions found on other gastrointestinal exams, such as capsule endoscopy or CT scan. The procedure is not used as a first line therapy and is performed only after careful evaluation by a specially trained gastroenterologist. Most procedures are done for bleeding lesions seen on capsule endoscopy, worrisome lesions or masses seen by other modalities, polyps in patients with hereditary syndromes, retained foreign objects, and small bowel strictures.
Therapies include treatment of bleeding lesions such as angioectasias, dilation of strictures using a hydrostatic balloon dilator, removal by snare or biopsy of polyps or small bowel masses, retrieval and removal of foreign objects or retained capsules, and biopsy of abnormal tissue. Balloon assisted enteroscopy has also been used in gaining access to parts of the gastrointestinal tract in patients with surgically altered anatomy.
Patients who are not medically stable should not undergo balloon assisted enteroscopy. Those who have had extensive abdominal surgeries may be poor candidates because of adhesions or altered anatomy which may prevent the scope from advancing.