Fig. 1. Double-balloon enteroscopy technique. (A) Endoscope inserted through the overtube (red arrow). (B) Endoscope balloon inflated. (C) Overtube advanced along the endoscope (blue arrow), and then the overtube balloon is inflated. (D) The overtube and endoscope are pulled back together, with two inflated balloons stabilizing and shortening the intestine. (E) After deflating the endoscope balloon, the endoscope is advanced again (red arrow).

Fig. 2. Single-balloon enteroscopy technique. (A) Endoscope inserted through the overtube (red arrow). (B) To hold the intestine, the endoscope is angled (red arrow). After deflating the balloon, the overtube is pushed forward (blue arrow). (C) The balloon is inflated, and then the endoscope is straightened (red arrow). (D) The overtube and endoscope are withdrawn to shorten the intestinal tract. (E) The endoscope is inserted as deeply as possible.

Fig. 3. Motorized power spiral enteroscopy (PSE) technique. (A) The overtube has spiral-shaped fins and is rotated by a motor controlled with a foot switch. (B) These fins gently grip the mucosa, allowing the endoscope to advance smoothly and reach deep into the small intestine. For antegrade PSE, the endoscope is advanced with motorized clockwise rotation and withdrawn with counterclockwise rotation.