A Different Way to Spay

This blog presents an idea that will be new for many of you and may be new for your veterinarians as well.  I thought presenting a novel idea would be a great way to kick of the new year! 

Taking 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, guess what happened!  They came up with a revised technique that accomplishes all of the objectives of the spay surgery with fewer complications!  How cool is that!

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, what we now know is that ovariectomy (OVE)- removal of just the ovaries sans uterus 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.

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.

What happens when we leave the uterus behind- is it not subject to becoming diseased later in life?  Here’s the good news- 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% 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 OVE’s rather than OVH’s 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 and provide a copy for him or her to read.  Perhaps OVE surgery is already their first choice.  If not, perhaps your vet will be willing to take a fresh look at performing this old fashioned surgery.

Wishing you many blessings for the new year,

Nancy Kay, DVM
Diplomate, American College of Veterinary Internal Medicine
Author of  Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Recipient, American Animal Hospital Association 2009 Animal Welfare and Humane Ethics Award
Recipient, 2009 Dog Writers Association of America Award for Best Blog
Recipient, 2009 Eukanuba Canine Health Award
Become a Fan of Speaking for Spot on Facebook 

Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot. There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot is available at Amazon.com, local bookstores, and your favorite online book seller.

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19 Responses to “A Different Way to Spay”

  1. Nanci Byers says:

    Would this type of spay surgery work the same way with cats? Just wondering.

    Thanks for an information article. I am taking a copy to my vet’s office tomorrow.

    Cheers!

  2. DA Hansen says:

    I would like to recommend the use of laser type surgery. When it was time to prepare for my dog’s spay procedure I found a vet clinic which uses the least invasive surgery method. It certainly worked well for my girl. She was quite happy to go visit the vets the next day. This is in contrast with my previous dog who never liked her vet after the spay operation.

  3. Kyla Duffy says:

    Thank you for the follow up feedback on this topic!

  4. China says:

    Thanks for your response Dr. Kay.
    After reading all the comments I’m more interested in some follow-up research on this subject. Thesis anyone? LOL Seriously though, there are interesting points brought up. From one who suffered miserably with my monthly friend in an age when you were just labeled a royal “B”, I’m wondering how much the ovaries and hormones apply to critters. After all, they have a tremendous effect on human females, doesn’t just make sense that there is also some effect on dogs/cats or what have you.
    As one who rescues kittehs, I’m thinking this surgery to be less complex, thus, less costly and “that’s a good thing!” Not to mention, the safety issues. But, not at the expense of the critters if it can lead to other problems.
    Definitely an area that needs more research and I believe, in time that will happen as our pets are becoming more and more a part of the family.
    Superb food for thought …

  5. China asked the question about whether or not this same information applies to cats. While I suspect that this would be the case, I am unaware of any research/literature that supports the success of feline OVE versus OVH. I hope someone somewhere will do the research and get it published. Thanks China for asking!

  6. Thanks for publishing this! I have been trying to tell other DVMs about the benefits of OE vs OHE for appropriate dogs and cats for a few years. I have consistently met with staunch resistance and total disinterest in even exploring the idea of doing OEs… even in spay and neuter clinics. I predict it will take 5 more years before OE becomes a common procedure in the USA for appropriate patients.

  7. Aldyth Kitchin says:

    Thank you for that really interesting article. Also for the opportunity to learn of other people’s opinions and experiences! I always learn something new from your articles.

  8. Martha Cook says:

    Nancy, this is so interesting. Thanks.

  9. Lisa says:

    Do you think the same info is true for felines?

  10. China says:

    Happy New Year, Dr. Kay!
    As usual, very interesting article … being more of a cat lover, I was wondering if you have any input for the kittehs?

  11. Sophia Yin says:

    Hi Allie:

    Thanks for your question on spaying in dogs and behavior. The article you’re referring to is: Can spaying make a dog’s behavior worse, which can be found at
    http://drsophiayin.com/blog/entry/can_spaying_make_dog_behavior_worse

    The study which the article was based on found that in dogs bred for reactivity (military german shepherd raised in kennel situation, which one might consider a reactive situation since dogs in these situations frequently get lots of practice barking at people who approach or walk through or dogs entering/exiting the kennel) were more reactive (it didn’t say aggressive) when spayed than the dogs that were not spayed. That is, they exhibited 10 reactive signals (such as barking, ears forward, staring, raised lip, lunging… compared to 5 reactive signals shown by the non-spayed dogs. By second testing at 5 months after spaying, scores had decreased in 2 of the 7 dogs (to same level as unspayed dogs).

    Overall this says that if you have a reactive intact female dog (barking, lunging, staring, snarling at people who come close) who’s the same test age as the dogs in the study (5-10 months) you may want to consider leaving the ovaries in.
    Alternatively it could mean that they may become more reactive at least temporarily. Given that she could become more reactive, you would want to gain some behavior modification skills to prevent increase in reactivity from occurring.

    Of course the issue with leaving the ovaries is the dogs may be more prone to developing mammary tumors.

  12. Hi Allie,

    You bring up some interesting points. A retrospective study (looking back in time) was done on a large group of Rottweilers, showed that Rottweilers spayed before one year of age had a higher incidence of osteosarcoma (a common type of malignant bone cancer in large breed dogs) than dogs that were left sexually intact. Mind you, there was no information about Rotties that were spayed after one year of age. There is also some information that suggests that the incidence of hemangiosarcoma (another common type of malignancy in large breed dogs) is higher in spayed rather than intact females. Again, because we are so used to spaying dogs before a year of age (we know that doing so prevents malignant breast cancer from occurring later in life) that there is no good data to help us know whether spaying after a year of age would change the incidence of hemangiosarcoma or osteosarcoma. What this means is that there is still a lot to be learned, and hopefully more studies are in the works.

    I don’t think that this really impacts the decision whether to spay via OVE or OVH, but for those of you with large breed dogs, it may change your opinion about when to spay, if at all. I am a BIG believer in spaying dogs, purely from the pet overpopulation point of view. I like it as a tool to prevent breast cancer and, personally, I would not want to deal with the hassle of a dog in heat. What would I do if a Rottie was under my care? I think I would try to wait until she was just over a year of age before spaying her.

    I will contact Dr. Yin to see is she is aware of any studies that support what you say she says. I’ve never had the impression that spaying correlates with increased aggression, but Dr. Yin certainly deals with far more aggressive dogs than do I.

    Thanks for the great questions.

  13. Kyla Duffy says:

    This is a great article! As a person who is heavily involved with rescue but has limited knowledge of veterinary medicine, I find this information very interesting. I’m not sure what your take is of Yin’s research via Allie’s comment, but I was a bit taken aback that someone would say spaying increases aggression in females. In fact, I get frustrated whenever someone says that spaying and neutering alters an animal’s personality. Logically, it makes sense that a change in hormones would have some emotional effect, but I think the body compensates. Again, I’m not speaking from a professional medical perspective here, but I wouldn’t consider myself completely unacquainted with the topic, as we’ve fostered 35 dogs in the past three years, several of whom I have taken for neutering. I don’t notice a change in their behavior, at least not for the worst. Sometimes the procedure helps to calm dominant dogs a bit, but otherwise I haven’t noticed any increased aggression or lethargy, which is also commonly mis-associated (in my opinion) with neutering. Would love your feedback…

  14. Kyla Duffy says:

    This is a great article! As a person who is heavily involved with rescue but has limited knowledge of veterinary medicine, I find this information very interesting. I’m not sure what your take is of Yin’s research via Allie’s comment, but I was a bit taken aback that someone would say spaying increases aggression in females. In fact, I get frustrated whenever someone says that spaying and neutering alters an animal’s personality. Logically, it makes sense that a change in hormones would have some emotional effect, but I think the body compensates. Again, I’m not speaking from a professional medical perspective here, but I wouldn’t consider myself completely unacquainted with the topic, as we’ve fostered 35 dogs in the past three years, several who I have taken for neutering. I don’t notice a change in their behavior, at least not for the worst. Sometimes the procedure helps to calm dominant dogs a big, but otherwise I haven’t noticed any increased aggression or lethargy, which is also commonly mis-associated (in my opinion) with neutering. Would love your feedback…

  15. Hi Tonya,

    In response to your question, the largest study comparing the two surgical procedures showed that there is no difference in the occurrence of adult onset urinary incontinence (leakage) between OVE and OVH.

  16. Allie says:

    I have a question – what about hysterectomy instead of ovario-hysterectomy? I know more about dogs than cats, but according to my research (and contrary to common knowledge) for large male dogs neuter causes a higher incidence of many dangerous diseases, and only decreasing the incidence of two comparatively minor diseases. Though I don’t recall the health consequences of spay on female dogs, Sophia Yin (a well known vet-behaviorist) claims that spay increases aggression and recommends leaving the ovaries if that is a concern. (Besides Yin, my major source was a review paper by Laura J. Sanborn, though I did read up on many of her claims and found them to be valid.)

    I have no reason to believe that this health information pertains to female cats, I have done no research on female cats. However, if a guardian were to determine that they preferred to avoid the changes brought on by removing the ovaries, what are the risks/benefits of leaving them?

  17. Tonya says:

    Dear Dr. Kay

    Does OVE help resolve canine incontenance that is sometimes seen in senior females that have been spayed?

  18. Lesley says:

    I would prefer leaving one, or part of an ovary. What worries me about spay, especially at an early age, is the absence of hormones created by an ovariectomy. Surely this is important to health.

  19. Margherite DeSanto says:

    Thank you, Dr. Kay. Whenever I read your blog, I get smarter and smarter! You are the best!