Recently I have had a number of inquiries from veterinarians (and clients) about the type of laparoscopic spay I perform. In general, there are 2 accepted techniques for performing a "spay": ovariohysterectomy (OVH) and ovariectomy (OVE). In an OVH both ovaries as well as the uterus are removed. By comparison, only the ovaries are removed during an OVE. The question is: which technique is better and why perform one over the other? The answer tends to stem from which technique a veterinarian was taught during their education. Generally speaking, veterinary colleges in North America have traditionally taught OVH, while colleges in Europe teach OVE. In recent years a decent amount of research has been done trying to determine if one technique has any advantages over the other. In short, both techniques seem to be equivalent from a medical standpoint. Comparisons of pain scores and recovery times showed no statistically significant difference between OVH and OVE using open (or traditional) technique. Laparoscopic spays show a very significant decrease in pain scores and recovery times when compared to traditional open surgery. However, when OVH and OVE were both performed laparoscopically they were deemed to be equivalent. With respect to future disease (mammary and uterine disease specifically), there was also no difference detected between the two procedures. In other words, there is no increased risk of mammary cancer, uterine cancer, or uterine infection if only the ovaries are removed. This makes sense because the ovaries are responsible for hormone production (primarily) and they are removed in both procedures. Conversely, I have been asked if I perform "tube tying" or a procedure where I remove only a piece of the ovarian horns and leave the ovaries in place (to prevent pregnancy only). I have not found any research suggesting this is a reasonable approach, and would have concerns with respect to future disease because the ovaries would still be present and producing hormone.
Bottom Line: Both OVH and OVE are excellent techniques for spaying dogs and cats, and the technique chosen is based on the individual surgeons experience and comfort level. There is no appreciable difference between the two procedures with respect to effectiveness, pain levels, or recovery time. Personally I tend to perform laparoscopic OVH because I went to veterinary college in Canada, but have performed laparoscopic OVE if a client or veterinarian requests that procedure.