By Dr. Nancy Kay
March 15, 2011
In January I wrote a piece called “A Different Way to Spay,” describing two techniques for performing spay surgeries. The method widely embraced in the United States is the ovariohysterectomy (OVH), in which both ovaries as well as the uterus are removed. The second way to spay — popular in many other countries — is the ovariectomy (OVE), in which only the ovaries are removed and the uterus is left behind.
My contention was (and remains) this: Why remove the uterus if doing so serves no useful purpose? The most common canine uterine disorder is pyometra (pus in the uterus), a disease that occurs only under the influence of ovarian hormones. Removal of the ovaries prevents pyometra from occurring.
The incidence of uterine cancer is exceedingly low (representing only 0.4% of all canine cancers). Additionally, a 2006 literature review comparing the two surgical techniques revealed no significant differences in long-term post operative complications such as uterine disease and urinary incontinence. The authors concluded that OVE was the preferred methodology.
So why do we continue to treat the uterus like the human appendix, and remove it whenever we get the chance? As my favorite song from “Fiddler on the Roof” tune goes, “Tradition!”. Itâ€™s simply the way our veterinary forefathers were taught, and the tradition has been passed down through the generations.
After my January blog post, many readers emailed to let me know that their family veterinarians were unwilling to perform OVE surgery. In some cases, their vets had not heard of OVE surgery nor were they inclined to learn about it. Many vets adamantly said, â€œNo way!â€ and some even declared that the notion of OVE was heresy. They attempted to scare their clients into believing that leaving the uterus behind would result in the dreaded outcome of pyometra.
I have to wonder, why spend so much money and time to go to vet school and then espouse such quackery? I just donâ€™t get it.
I encouraged these folks to consult with board-certified surgeons in their area to either have the surgery performed by them, particularly if cost was not an issue, or to attempt to find out from the specialist which general practitioners in the community were open to performing OVE surgery.
In all honesty, I felt discouraged by these emails — discouraged by the notion that some of my colleagues are so set on doing things the same old way, in spite of new information. In some cases, the familiar saying â€œYou canâ€™t teach an old dog new tricksâ€ may be most applicable to the dogâ€™s doctor.
All the news isn’t bad, however. I am delighted to see that a talk called â€œReview of Ovariohysterectomy Versus Ovariectomyâ€ will be presented at the upcoming annual meeting of the American Veterinary Medical Association. The more veterinarians thinking about this issue the better.
Additionally, educators are catching on and some veterinary colleges in the United States are currently teaching their students how to perform OVE surgery.
In my January post, I discussed European research that found the OVE resulted in shorter surgery times and fewer complications, and since then, one new study was published that found the two procedures differed only in the length of the incision.
The study, performed by researchers at Utrecht University and published in the January 15, 2011, issue of the Journal of the American Veterinary Medical Association compared surgical variables (blood loss, length of incision, duration of surgery) and short-term post-operative complications in 40 healthy dogs undergoing ovariohysterectomy versus ovariectomy:
Significant differences in total surgical time, pain scores, and wound scores were not observed between dogs that underwent OVH and dogs that underwent OVE via standardized protocols.
Apparently the only significant difference was the length of the incision (longer when the uterus was removed), yet the length of the incision did not significantly influence the duration of surgery. I love this point because it is a fabulous demonstration of how evidence-based medicine can contradict intuition.
That being said, itâ€™s tough to know that this outcome truly applies in the real world — all of the surgeries in this study were performed by one board-certified surgical specialist. The results of this study suggest that OVE and OVH procedures have equivalent outcomes in terms of length of procedure and short-term complications. Even if this is true across the board, my question remains: Why remove the uterus if doing so serves no useful purpose?
I realize Iâ€™ve not addressed the topics of laparoscopic (minimally invasive) spay surgery or at what age (some might question if at any age) dogs should be spayed — all good fodder for future blog posts. So many topics, so little space! Now, letâ€™s hear your comments.