Apparatus comprising: a sleeve adapted to be slid over the exterior of an endoscope； a proximal balloon secured to the sleeve； an inflation/deflation tube carried by the sleeve and in fluid communication with the interior of the proximal balloon； a push tube slidably mounted to the sleeve； and a distal balloon secured to the distal end of the push tube, the interior of the distal balloon being in fluid communication with the push tube, wherein the distal balloon is capable of assuming a deflated condition and an inflated condition, and further wherein when the distal balloon is in its deflated condition, an axial opening extends therethrough, the axial opening being sized to receive the endoscope therein, and when the distal balloon is in its inflated condition, the axial opening is closed down.
