An apparatus may be used to form an opening in a sinus wall. The apparatus comprises a first cutting member and a second cutting member. The first cutting member comprises a helical blade. The second cutting member is slidably disposed about the first cutting member. The second cutting member comprises a sharp distal edge. An outer sheath is slidably disposed about the first and second cutting member. The sheath may be retracted to uncover the helical blade. The second cutting member may be advanced over the first cutting member to form a circular opening in the sinus wall. The sheath may include an obliquely angled distal edge. A cleaning instrument may be used to clean debris from the first cutting member.