An expandable electrode cuff of an implantable stimulation system that includes a base member, a first flange member extending from a proximal end along a first side wall of the base member to a first distal end, and a second flange member extending from a proximal end along a second side wall of the base member to a second distal end. The first flange member extends over both a top wall of the base member and the second flange member, and the second flange member extends over the top wall to form a lumen. The electrode cuff is capable of being advanced between a first position corresponding to both flange members extending over the top wall, a second position corresponding to the first flange member not extending over the top wall and the second flange member extending over the top wall, and a third position corresponding to both of the flange members not extending over the top wall.