The instrument disclosed may comprise a tube assembly further comprising substantially coaxially situated and relatively longitudinally movable tubes, supporting and operating an end effector that may be adapted for insertion into and through the urethra, and adapted for use in effecting the anastomosis of a patient's bladder and urethra following a prostatectomy. In alternative embodiments the tube assembly may comprise a rod and two tubes, three tubes, a rod and three tubes, or four tubes. The method disclosed may comprise inserting an instrument having an end effector into the bladder lumen, and using the end effector to urge the bladder wall to the pelvic floor and drive an anchor through the bladder wall and into the pelvic floor.