A system for performing minimally invasive procedures in a body lumen may include a flexible catheter having a plurality of lumens including a main lumen configured to receive an endoscope and at least one tool lumen; a first working instrument slidably disposed within a first tool lumen of the at least one tool lumen; a plurality of support elements disposed at a distal end of the catheter, the plurality of support elements being configured to shift between delivery and expanded configurations, wherein in the expanded configuration, the plurality of support elements forms an expanded cage to reshape the body lumen and form a working space; wherein at least one of the plurality of support elements is a tubular shaft having an opening proximate the working space; and a filament extending through the tubular shaft to a clip disposed outside the opening, the clip being manipulatable by the first working instrument.