The proper technical term for the surgical alteration of an animal is “neutering”, regardless if it is male or female. The castration, or orchidectomy, is the surgery performed on male animals. In this case, both testicles are removed.
While Neutering male dogs and cats , both testicles are removed through a single small incision and the blood vessels and the vas deferens (sperm cords) are tied with sutures. In dogs we close the inside incision with suture and put sutures in the skin as well. Cats usually do not need sutures in either the inside layer or the skin.