Improved methods and devices for performing an endoscopic surgery including a system for performing minimally invasive procedures including a flexible catheter having 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 defines a first space configured and dimensioned to receive an endoscope. The first flexible tube and second flexible tube are fixed at a proximal portion and configured to float within the first lumen of the catheter. First and second flexible guides are slidably positioned within the first and second flexible tubes and dimensioned to receive a first instrument for axial movement therein, the first and second flexible guides movable to an angled position with respect to a longitudinal axis. 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 lumen.