There are many reasons for which your veterinarian may recommend that you spay your female dog or cat. Spaying (surgically sterilizing) your pet does more than just prevent her from having puppies or kittens. It has been well established that not spaying your female dog or cat will increase her risk for certain cancers, including malignant mammary tumors. It will also increase her risk of developing a condition called pyometra (a potentially life threatening infection of the uterus). The unwanted behavioral and physical changes that happen to your pet during her heat cycle will also be avoided. We recommend discussing both the potential health benefits and appropriate age at which to spay your pet; however, it is also important to know that there is more than one way in which your pet can undergo this surgical procedure.
Ovariohysterectomy is a surgical procedure in which both ovaries, both uterine horns and the majority of the uterine body are removed. It is the most common method of spaying dogs and cats in the United States and is the technique that is generally taught in veterinary colleges in the United States. To perform this procedure, an incision is made on an anesthetized patient along the center of her abdomen. Her surgery is performed from this incision and then the abdominal wall is sutured closed prior to recovery.
Ovariectomy is a surgical procedure in which both ovaries and only a small portion of each of the uterine horns are removed. With this procedure, the majority of the uterine horns and the entire uterine body are left within the body. This method of spaying a dog or cat also requires an abdominal incision that is closed at the conclusion of the surgery, although the incision itself is smaller than one performed in an ovariohysterectomy. Due to the smaller incision and minimal amounts of the uterus being removed, the ovariectomy can be thought of as a less invasive procedure. Ovariectomies are being performed more routinely in the United States and have been performed in Europe for multiple decades.
Comparing the two methods
With a bit of background on both procedures, we can now discuss the pros and cons of each method of surgery. Although spaying a dog or cat is considered a routine procedure, and complications are uncommon, it is important to note the most likely risks with these procedures.
The most common complication is mild incisional inflammation. An incisional dehiscence (sutures being broken or coming undone along the incision), on the other hand, is considered a major complication. Since a smaller incision is needed to perform an ovariectomy, it may be less likely to have a major complication associated with the incision. However, this risk is present in both methods of the procedure.
Hemorrhage (bleeding) intra-operatively and post-operatively can also occur as there are large blood vessels that feed the ovaries and uterus. The risk for hemorrhage increases when a dog or cat is in heat or has had multiple heat cycles. Ovariectomies may limit risk for hemorrhage since the uterine body is left intact and the blood vessels feeding this structure are not impacted.
If spaying your pet is being paired with another procedure, such as a gastropexy (a procedure that helps to prevent bloat, or GDV, in certain breeds of dogs), an ovariectomy may be a good option for your pet. The incision needed to perform the GDV is often made by extending the spay incision cranially (towards the chest or head). If the uterus is not being removed, as with an ovariohysterectomy, this can make your incision much smaller, which will ideally make your pet more comfortable during recovery and limit risk for incisional dehiscence.
One of the perceived downsides of the ovariectomy is that uterine tissue is left in place. This can become problematic for two reasons, although complications because of this are rare. One of the biggest problems would be if your female pet develops urinary incontinence later in life. For some of our female patients that develop urinary incontinence, signs may be responsive to estrogen therapy. However, if their uterus is present (i.e. they are not spayed or had an ovariectomy) it is not advised to give this hormone therapy, as it would put them at risk for developing pyometra (an infection in their uterus). Thankfully, there are other medications available for the treatment of urinary incontinence, but an ovariectomy in this circumstance would limit your treatment options.
When the uterine tissue is left in place (after ovariectomy is performed) there is also a risk for development of a uterine tumor, though uterine tumors are very uncommon in dogs (less than 0.4% of all cancer seen in female dogs). If a uterine tumor were to occur, though majority are benign (curative with removal,) there is a rare chance that it could be malignant. According to a recent article in the Journal of the American Veterinary Medical Association there is approximately a 0.003% chance of your female pet developing a malignant uterine tumor.
There are many benefits to spaying your female dog or cat. Please know that there are also options as to which surgical method is used to perform your pet’s spay. There are pros and cons to each method, and we encourage you to discuss these with your veterinarian in order to help you decide which is the best treatment plan for your furry friend. Here at Blue Sky Veterinary Clinic we have doctors that are happy to go over these options with you and are capable of performing either of these procedures.