In sclerotherapy your piles will be injected with an oily solution, which makes them shrivel up. It's used for 1st or 2nd degree piles. Infrared coagulation or laser is where infrared light is used to seal the veins above the pile causing it to shrink. Cryosurgery destroys the pile by freezing it-the pile will later shrink and fall off. Bipolar diathermy and direct current electrotherapy is where an electrical current is used to burn the pile off.
Attribution: BUPA