An insertion device for use during a surgical procedure to enlarge an opening in a patients tissue to facilitate access to an internal treatment site with a surgical instrument, the insertion device comprising an anoscope including a flange, an elongate body having proximal and distal ends extending distally from the flange along a longitudinal axis, and a pair of wings extending outwardly from the flange and curving proximally in an arcuate fashion in a direction away from the distal end, each of the wings including a projection positioned along a peripheral edge thereof and extending in a proximal direction and forming a raised lip extending along the edge, wherein the anoscope includes a configuration that is symmetrical about a plane extending along the longitudinal axis that bisects the flange.
