A system for performing minimally invasive procedures in a body lumen of a patient including a flexible catheter (105) having a first lumen configured and dimensioned to receive an endoscope therethrough and a second lumen configured and dimensioned to receive a first flexible tube or endoscopic working instrument therethrough. The first flexible tube is movable through the second lumen and has a distal portion including a first curve extending in a first direction with respect to the longitudinal axis and a second curve extending in a second different direction with respect to the longitudinal axis. A retractor system (150) is positioned at a distal portion of the catheter and is movable from a non-expanded insertion position to an expanded position forming an expanded cage to form a larger working space. The distal portion of the first flexible tube is movable within the expanded cage.
