A system for performing procedures in a working space within a body lumen of a patient, the system comprising: a flexible catheter having an inner wall, an outer wall, a first lumen, a first flexible tube positioned in the first lumen, and a second flexible tube positioned in the first lumen, the first lumen defining a first space configured and dimensioned to receive an endoscope, the first flexible tube and the second flexible tube fixed at a proximal portion and configured to float within the first lumen of the flexible catheter; the first flexible tube configured and dimensioned to receive a first instrument for axial movement therein, the first instrument having a longitudinal axis and a distal portion movable to an angled position with respect to the longitudinal axis of the first instrument; the second flexible tube configured and dimensioned to receive a second instrument for axial movement therein, the second instrument having a longitudinal axis and a distal portion movable to an angled position with respect to the longitudinal axis of the second instrument; and a working space expanding system positioned at a distal portion of the flexible catheter, the working space expanding system movable from a non-expanded insertion position to an expanded position forming an expanded region to expand the working space within the body, the distal portion of the first instrument and the distal portion of the second instrument movable to angled positions within the expanded region, characterized in that a first cylindrical distal tube is positioned within the flexible catheter at a distal end and attached to the inner wall thereof, wherein a distal end of the first flexible tube is positioned within the first cylindrical distal tube and secured thereto. a flexible catheter having an inner wall, an outer wall, a first lumen, a first flexible tube positioned in the first lumen, and a second flexible tube positioned in the first lumen, the first lumen defining a first space configured and dimensioned to receive an endoscope, the first flexible tube and the second flexible tube fixed at a proximal portion and configured to float within the first lumen of the flexible catheter; the first flexible tube configured and dimensioned to receive a first instrument for axial movement therein, the first instrument having a longitudinal axis and a distal portion movable to an angled position with respect to the longitudinal axis of the first instrument; the second flexible tube configured and dimensioned to receive a second instrument for axial movement therein, the second instrument having a longitudinal axis and a distal portion movable to an angled position with respect to the longitudinal axis of the second instrument; and a working space expanding system positioned at a distal portion of the flexible catheter, the working space expanding system movable from a non-expanded insertion position to an expanded position forming an expanded region to expand the working space within the body, the distal portion of the first instrument and the distal portion of the second instrument movable to angled positions within the expanded region, characterized in that a first cylindrical distal tube is positioned within the flexible catheter at a distal end and attached to the inner wall thereof, wherein a distal end of the first flexible tube is positioned within the first cylindrical distal tube and secured thereto.