Saturday, January 29, 2011

A Different Way to Spay

by Nancy Kay, DVM

This post presents an idea that will be new for many of you and may be new for your veterinarians as well.

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.

***

DR. NANCY KAY wanted to become a veterinarian for just about as long as she can remember. Her veterinary degree is from Cornell College of Veterinary Medicine, and she completed her residency training in small animal internal medicine at the University of California—Davis Veterinary School.

Dr. Kay is a board certified specialist in the American College of Veterinary Internal Medicine and published in several professional journals and textbooks. She lectures professionally to regional and national audiences, and one of her favorite lecture topics is communication between veterinarians and their clients.   Since the release of her book,
Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life, Dr. Kay has lectured extensively and written numerous magazine articles on the topic of medical advocacy.  She was a featured guest on the popular National Public Radio show, Fresh Air with Terry Gross.

Dr. Kay is a staff internist at VCA Animal Care Center, a 24-hour emergency/specialty care center in Rohnert Park, California. As a way of providing emotional support for people with sick four-legged family members, Dr. Kay founded and helps facilitate the VCA Animal Care Center Client Support Group.  She also facilitates client communication rounds for VCA Animal Care Center employees.

Dr. Kay was selected by the American Animal Hospital Association to receive the 2009 Hill’s Animal Welfare and Humane Ethics Award.  This award is given annually to a veterinarian or nonveterinarian who has advanced animal welfare through extraordinary service or by furthering humane principles, education, and understanding.  The Dog Writers Association of America selected Dr. Kay for two awards.  The first was the 2009 Eukanuba Canine Health Award recognizing
Speaking for Spot as the publication that best promotes the health and well being of dogs. The second award was for the Best Blog of 2009 (www.speakingforspot.com/blog).

Dr. Kay’s personal life revolves around her husband (also a veterinarian), her three children (none of whom aspire to be veterinarians) and their menagerie of four-legged family members. When she’s not writing, she spends her spare moments in the garden or riding along the beach atop her favorite horse. Dr. Kay and her family reside in Sebastopol, California.


Further Reading:
Have we been doing it wrong? Ovariectomy vs. ovariohysterectomy in small-animal practice

4 comments

  1. This is a great article for a future owner of a female pup! I have been debating when or if to spay her... and really haven't been able to figure it out. I think I might ask for an OVE when the time comes to spay her.

    ReplyDelete
  2. There is also a vet in my state that does vasectomies and tubal ligation of dogs. These dogs still act like entire dogs, but cannot contribute to the dog population.

    Vasectomies and tubal ligation can be done at an early age and doesn't have the implications that early testical or ovary removal has on young dogs' development.

    ReplyDelete
  3. Hi Tegan. Sounds cool. There are other medical advantages to spay/neuter, so the general belief seems to be that the main question isn't really whether or not but when.

    ReplyDelete

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