Small bowel: the last frontier

Abstract

As a result of the development of endoscopic equipment, we endoscopists have played an increasingly relevant role in the diagnosis and management of esophageal, gastric, duodenal, colonic, biliary, and pancreatic conditions. The small bowel seemed out of reach, much too far from our entry doors -the mouth and the anus. The paradigm regarding this frustrating situation was obscure upper gastrointestinal bleeding. Up to 5% of patients with gastrointestinal bleeding were -and still are in many cases-repeatedly explored, admitted, and operated upon to no avail, with patients forced to cope with morbidity as inherent not only to their condition but also to such unfruitful examinations (1-3).The advent of early push enteroscopes hardly advanced 50 to 90 cm (4) into the winding, distensible jejunum. With just these few centimeters, however, we increased diagnostic yield from 8 to 35%. But we were still far removed from reaching the average 6.7 m of small bowel (5), even more so if we consider that average length beyond Treitz's angle, as reached in some enteroscopy series, was shorter than 25 cm (6). Radiographic explorations using a barium contrast material, including enteroclysis, are also of little help. Bleeding in excess of 0.5 cc/min is required for Tc 99m -labeled red blood cell scans to have a yield above 20%, and anyway this exploration will not appropriately locate the bleeding point so that lesions may be identified during surgery (7). Arteriography, while allowing therapeutical measures, requires active bleeding during the procedure, and may be aggravated by serious complications (8).We had to reach further then. First to describe and perform a total enteroscopy was Hiratsuka in 1971 (9), using the ropeaway procedure, only to be followed shortly afterwards by Tada (10), who reported on another total exploration using a sonde enteroscope. Both methods were time-consuming and costly in terms of complications, and thus did not become widespread; intraoperative enteroscopy remained the gold standard in the diagnosis and management of small-bowel conditions (1). With this, diagnostic accuracy increases to 75% (11) but surgical morbidity and the common development of postoperative ileus advise that this examination be restricted to patients with obscure intestinal bleeding as a last option.The next step came a short time ago. The capsule designed and marketed by Given Imaging allows a direct, painless view of virtually the whole small bowel using a small, wireless device. The capsule currently in use is 11 mm in diameter and 26 mm in length, acquires 2 images per second, and captures and transmits around 50,000 pictures to an external recorder during its 8-hour battery life. Images are sent from this recorder to a workstation where they are reviewed by the examiner following their conversion into a video format. The capsule is minimally uncomfortable for the patient, who may be explored while out of hospital on an ambulatory Small bowel: the last frontier