Features December 2010 Issue

A New and Safer Way to Spay Your Puppy

Fewer complications result from removal of only the dog’s ovaries.

Making a fresh look at the things we take for granted can be wonderfully enlightening. Sometimes, the little light bulb overhead begins to sizzle and sparkle, illuminating a new and better way of doing things. Consider this example: When some savvy veterinarians took a fresh look at performing spays, a surgery we’ve been doing the exact same way for decades, they came up with a revised technique that accomplishes all of the objectives of the spay surgery with fewer complications. How cool is that?

No wonder female dogs are sore during recovery from conventional spay surgery – removal of the ovaries and the uterus requires the veterinarian to physically manipulate and cut away quite a bit of tissue. Removal of the ovaries alone is faster and less traumatic, and the patients recover more quickly.

Spay is the term used for neutering a female dog. As I was taught in veterinary school, the medical jargon for spaying is ovariohysterectomy (OVH). “Ovario” refers to ovaries, “hyster” refers to uterus, and “ectomy” means removal of. In other words, spaying the traditional way involves surgical removal of the uterus and both ovaries. The objectives of the spay surgery are to render the dog infertile, eliminate the mess and behavioral issues associated with a female dog in heat, and prevent diseases that may afflict the uterus and ovaries later in life.

Thanks to some innovative veterinarians, we now know that ovariectomy (OVE) – removal of just the ovaries, leaving the uterus in place – accomplishes these objectives just as effectively as does the OVH. And, here’s the icing on the cake: removal of the ovaries alone results in fewer complications when compared to removal of the ovaries and uterus combined.

Female canine anatomy
Here’s a simple short course in canine female reproductive anatomy and physiology that will help explain why leaving the uterus behind makes sense. The shape of the uterus resembles the capital letter “Y.” The body of the uterus is the stem and the two uterine horns represent the top bars of the “Y.” An ovary is connected to the free end of each uterine horn by a delicate structure called a fallopian tube (transports the egg from the ovary into the uterus).

While the uterus has only one purpose (housing developing fetuses), the ovaries are multitaskers. They are the source of eggs of course and, in conjunction with hormones released by the pituitary gland, ovarian hormones dictate when the female comes into heat and becomes receptive to the male, when she goes out of heat, when she ovulates, and when her uterus is amenable to relaxing and stretching to house developing fetuses.

After the ovaries (and the hormones they produce) have been removed from the body, the uterus remains inert. The dog no longer shows symptoms of heat, nor can she conceive. Additionally, any chance of developing ovarian cystic disease or cancer is eliminated.

Better outcome
What happens when we leave the uterus behind? Isn’t it subject to becoming diseased later in life? Actually, the incidence of uterine disease in dogs whose ovaries have been removed is exceptionally low. Pyometra (pus within the uterus), is the most common uterine disorder in unspayed dogs, and typically necessitates emergency surgery to remove the uterus.

Without the influence of progesterone, a hormone produced by the ovaries, pyometra does not naturally occur. The incidence of uterine cancer is extremely low in dogs (0.4 percent of all canine tumors) – hardly a worry, and studies have shown that the frequency of adult onset urinary incontinence (urine leakage) is the same whether or not the uterus is removed during the spay procedure.

If you are not already convinced that the “new spay is the better way,” consider the following complications that can be mitigated or avoided all together when the uterus remains unscathed:

  • Compared to an OVH, an OVE requires less time in the operating room. This translates into decreased likelihood of anesthetic complications.
  • Removal of the uterus requires that the surgeon perform more difficult ligations (tying off of large blood vessels and surrounding tissues with suture material before making cuts to release the organs from the body). A uterine body ligation that isn’t tied quite tightly enough can result in excessive bleeding into the abdominal cavity and may necessitate blood transfusions and/or a second surgery to stop the bleeding.
  • The ureters (thin delicate tubes that transport urine from each kidney to the bladder) run adjacent to the body of the uterus. If a surgeon is not being extremely careful, it is possible to ligate and obstruct a ureter in the course of removing the uterus. This devastating complication requires a second corrective surgery; however, damage to the affected ureter and adjoining kidney may be irreversible.
  • Removal of the uterus occasionally results in the development of a “stump granuloma” – a localized inflammatory process that develops within the small portion of uterus that is left behind. When this occurs a second “clean up surgery” is typically required.
  • We know that the degree of post-operative patient discomfort correlates with the degree of surgical trauma. No question, of the two surgical options the OVH creates more trauma.

European veterinarians have been performing OVEs rather than OVHs for years. In fact, the bulk of the research supporting the benefits of leaving the uterus behind has been conducted in Europe.

Slowly, veterinarians in the United States are catching on, and some veterinary schools are now preferentially teaching OVE rather than OVH techniques to their students.

What should you do if you are planning to have your dog spayed? Talk with your veterinarian about this article. Perhaps OVE surgery is already his or her first choice. If not, perhaps your vet will be willing to take a fresh look at performing this old-fashioned surgery.

Nancy Kay, DVM, is a Diplomate of the American College of Veterinary Internal Medicine (ACVIM) and recipient of the  American Animal Hospital Association 2009 Animal Welfare and Humane Ethics Award. She is also author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life, and a staff internist at VCA Animal Care Center in Rohnert Park, California.

Comments (15)

This the the opposite of what you should do. The correct surgery to do is ovary sparing surgery and removal of the uterus. That way the dog has it's hormones but can't get pregnant.

Posted by: 376NYC | November 6, 2014 10:56 PM    Report this comment

I thought when there is discussion/use of the term "early" spay, it is when they are weeks old, before adoptions at shelters, i.e. not even 8 weeks, or just. I am old school and when my pup and I adopted each other, I had the paperwork revised to say spaying would not take place until she was at least 6 months old.

Beyond that, our vet was one of the only vets a few years back doing laproscopic spays with just removal of the ovaries, and I can tell you how well my little one did, and how speedy her recovery. The whole process when you compare the two is so much gentler and kinder, even if more expensive, you just can't not do it once you know.

Posted by: robin r | November 6, 2014 6:16 PM    Report this comment

I have a question more then a comment regarding partial spay, is it more beneficial to keep the ovaries in place or the uterus? I see uterus removal looks to be more common rather then ovaries.

Posted by: Sofia Baby Dog | February 28, 2014 3:12 PM    Report this comment

I disagree with this article. Too much is coming to light now about just how important canine hormones are for the healthy maturing of both male and female canines. I have had dogs for over 50 yrs and have never had an unplanned litter of puppies. Most of my figs have been bitches and were not spayed until 5-6 yrs old, usually due to abnormal heat cycles. My own vet has changed his mind recently saying that he will not encourage early spay or neuter instead encouraging owners to wait till growth plates have closed and growing is complete. My current young dogs will have tubal ligations or vasectomies if necessary. The hormones removed so easily may have needed impact on growth etc

Posted by: AnnM | August 8, 2013 7:48 PM    Report this comment

There is a downside to spay/neuter that is not discussed here. Neutering males, especially, is much more harmful to their growth and health than beneficial. With females, there is more to consider, but I have come to believe through experience that my goldens are better off intact and managed than surgically altered and more at risk for hemangiosarcoma, lymphoma, osteosarcoma, and mast cell - the top four killers of goldens. Why increase a risk that you already have to deal with? How does that improve anything? In twenty-two years I've had two pyos(in 1996 and 1999, caught them very early, and my fit, trim females recovered as from a regular mature spay. That's a less than ten percent risk in my own dogs. I'll live with that.

Posted by: Deirdre D | August 8, 2013 12:46 PM    Report this comment

What about all the research this is coming out saying dogs need their hormones as protection from some types of cancer and orthopedic problems?

Posted by: pat J | August 8, 2013 12:21 PM    Report this comment

While I still was in vet school, we had a bitch with a stump pyometra. So yes, you have risk of infection. And one suggested only to ligate, then you have no advantage except no reproduction. You will run risk of pyometra and mammary tumors if you leave the ovaries. And with males and females, if you only ligate, you still have the behaviors of entire dogs. Males will still get prostate hyperplasia, testicular cancers, and so on.

Posted by: Michele C | April 30, 2013 10:09 PM    Report this comment

I think you have this all backwards! Just as in human females, you leave at least one ovary if at all possible and remove the uterus! Sure it is easier for the Vet to remove the ovaries, but as you state yourself, you are removing the multitasking organ and leaving the one that has only one purpose, and that is to carry fetuses.

The ovaries are needed to keep the rest of the endocrine system in balance (multitasking), not simply to create eggs for fertilization.

You now have left and organ that has no purpose, removed the ovaries that regulated the uterus and told it what to do. I agree totally with the above posted who stated, you have now left a female totally open to pyometra!!! Pyometra is a bacterial infection and not caused by the hormones, but by bacteria. The cervix is allowed to be relaxed and open after a female comes into season (which is when it is most likely for the bacteria to enter the uterus and allow pyometra to develop.

Posted by: jerrier | July 16, 2011 1:35 PM    Report this comment

Dear Dr. Kay: Does this hold true for laproscopic surgery as well? Any comments on laproscopic versus conventional surgery for spay? Thank you.

Posted by: Jose M | March 16, 2011 6:20 AM    Report this comment

Dr. Nancy - It's been ten years since we had a puppy and we will be getting a male. Is there any new thinking about neutering? Just wondering about a vasectomy vs.a typical neutering. Thanks...

Posted by: BARB G | January 2, 2011 9:52 AM    Report this comment

to Nancy K; I read the article and since "I" myself had a dog that was spayed (ovaries also) that had stump pyometra (the spay type left a small uterine stump) and I know of several other such cases also, pyometra can indeed occur without ovaries

ADDITIONALLY if the dog ever had a heat cycle before the Ovary removal surgery only is done, she will already have had hormone changes to the uterus

Personally if you are removing any body parts (ie ovaries only surgery or the uterus only surgery a few vets are doing) then I say take it all out and avoid all health risks.

Posted by: rottlady | December 20, 2010 2:38 PM    Report this comment

This is in response to Rottlady's comment. I encourage you to have another look at the article that explains how pyometra occurs- can only happen if the dog is under the influence of progesterone- a hormone produced by the ovaries. No ovaries means no progesterone which means no pyometra. The only weird way a pyometra could occur is if the dog received some sort of progesterone compound. For example, some women take progesterone to help prevent miscarriage- I suppose if a dog accidentally ingested this medication, a pyometra could occur. Chances of this are so very slim that I hardly view it to be a valid argument. I hope this provides some clarification.

Best wishes,

Dr. Nancy Kay

Posted by: Nancy K | December 19, 2010 12:47 PM    Report this comment

while this surgery is safer at time of surgery, it can put the dog at risk later in life. leaving a uterus means leaving the risk for pyometra there. Older females are at a very high risk for pyometra (uterus infection) and emergency pyometra surgeries are both costly and very high risk

No thanks. When I spay it will be a full spay (uterus and ovaries) to both stop heat cycles/pregnancy risk AND prevent pyometra

Having done 2 pyo spays in the past I have no wish to repeat the process ever again

Posted by: rottlady | December 17, 2010 11:06 AM    Report this comment

You read the WDJ?

Posted by: JOAN H | December 7, 2010 9:53 AM    Report this comment

I prefer 100% natural dogs.

Posted by: Sandra S | November 29, 2010 6:49 PM    Report this comment

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