What other endoscopic tests are available to evaluate the small bowel in patients with obscure GI bleeding?
Various “long endoscope” endoscopy tests permit diagnosis and potential treatment.
• Push enteroscopy uses an enteroscope that is similar, but substantially longer than a standard UGI endoscope. The longer enteroscope allows intubation more distally, typically into the proximal jejunum, approximately 50 cm beyond the ligament of Treitz.
• Spiral enteroscopy uses a 118-cm long overtube with a soft, raised, spiral helix at its distal end (Spirus Medical Inc., Stoughton, MA) that is placed over a long enteroscope. The overtube is affixed to the enteroscope via a coupling device that permits rotation of the overtube. The spiral ridge of the overtube engages the small bowel plicae circulares (folds) during clockwise rotation like a screw into wood. The enteroscope is advanced by rotating the overtube clockwise, which pleats the small bowel onto the overtube. The most common complication is self-limited mucosal trauma from spiraling over mucosal folds. There is a low rate of major complications of 0.4%, including a 0.3% rate of GI perforations. Spiral enteroscopy is not widely available.
• Double-balloon enteroscopy consists of a 200-cm long enteroscope with a latex balloon at its tip, and a 145-cm long soft overtube with another latex balloon at its tip, and pumps to inflate both balloons. The enteroscope is advanced during repetitive cycles of inflation and deflation of the individual balloons coupled with alternating advancement of the enteroscope or overtube. The diagnostic yield for the indication of obscure bleeding ranges from 40% to 80%. The rate of major complications is approximately 0.7%, with a 0.4% rate of GI perforation.
• Single-balloon enteroscopy uses a 140-cm long overtube and a 200-cm long enteroscope. The overtube is equipped with an inflatable balloon at its tip to aid in endoscope advancement through the small bowel by pleating of small bowel on the overtube. The average depth of small bowel insertion ranges from 150 to 250 cm. Single-balloon enteroscopy has a yield somewhat lower than double-balloon enteroscopy, with a diagnostic yield of 40% to 65%. Complications include abdominal pain, pyrexia, mucosal tears, aspiration pneumonia, cardiovascular events, and perforation. The rate of GI perforation is approximately 0.4%.