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Snares designed to position and tighten fine-gauge, flexible, adjustable wire loops around a region of rectal tissue (e.g., polyps) for mechanical or electrosurgical resection and hemostasis. These devices typically consist of a hollow tubular straight or bent structure (e.g., a cannula, typically with a length of 8 to 18 inches/20 to 45 cm) with one or more adjustable wire loops (rings) that protrude at the working end; frequently they include a stationary loop and a sliding loop. The snare loops are made of monofilament or braided wires that may be attached at the proximal end to an electrosurgical (usually monopolar) unit that provides circulation of radio-frequency electric current between the isolated metal loop (i.e., acting as an active electrode) and an external neutral electrode to heat the tissues and facilitate resection and cauterization. Reusable and single-use (i.e., disposable) rectal snares are intended mainly for electrosurgical removal of polyps, tumors, and other abnormal tissue from the rectal mucosa, but devices that provide only mechanical resection are also available.
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