Methods and devices are provided for selectively stiffening a surgical device. In one exemplary embodiment a surgical device is provided that includes a flexible elongate insertion element and a stiffening element that extends along at least a portion of the insertion element. The insertion element can be, for example, an endoscope or a sheath configured to be disposed over an endoscope. The stiffening element can be configured to selectively stiffen when an outside force, such as a vacuum force, is applied thereto. In one embodiment the stiffening element includes a plurality of elongate members disposed in a flexible sheath. When the vacuum force is applied, the sheath can be configured to engage the elongate members to maintain the elongate members in a fixed, stiffened position, thereby stiffening at least a portion of the flexible elongate insertion element coupled thereto. Various methods for stiffening an insertion instrument, such as an endoscope, are also provided herein.
