A urethral scaffold is provided for expanding a portion of the urethra that extends through the prostate. The scaffold is expandable and has a plurality of undulating circumferential members disposed between a proximal end and a distal end of the scaffold. A central section of the scaffold has a width that exceeds the width at the distal end of the scaffold. The scaffold is made of a material that reacts with urine or with tissue surrounding the urethra to reduce the volume of the scaffold such that the scaffold can self-explant without an interventional procedure.