Spay/Neuter Techniques

Most pet families will be advised to have their new puppy spayed or neutered by either their breeder, their veterinarian, or their municipality.  Surgical sterilization prevents unwanted litters and helps prevent overpopulation. It also provides a number of health, behavioural, and social benefits for the pet and pet owner.

Surgical techniques for canine spay and neuter vary by practitioner, region, and by equipment available.  In this article, we will explore conventional spay/neuter techniques, as well as some newer, or less common approaches.

Spay (Surgical Sterilization of the Bitch)

Ovariohysterectomy

In North America, the most conventional sterilization technique is ovariohysterectomy:  the surgical removal of both ovaries and most of the uterus via a midline abdominal incision.  The benefits of this procedure (other than birth control), include the removal of the hormone-secreting ovaries.  This means that heat behaviour will cease, male dogs will not be attracted, and future uterine infection (pyometra) will be prevented.  If ovariohysterectomy is performed prior to the second heat, the risk of mammary cancer will be significantly reduced.  Depending on the dog’s conformation and the surgeon’s experience and preference, incisions may be large or small.  Larger incisions offering the benefit of excellent visualization of the anatomy and accommodate other procedures, such as gastropexy. While some pet owners may balk at the idea of a long incision, they are reminded that incisions heal side-to-side rather than end-to-end, and that surgical safety trumps aesthetics.  One of the main benefits of this technique is the overwhelming experience and comfort that veterinarians in North America have with the protocol. Shelter and rescue organizations welcome the easily-identified scar for quick confirmation of an animal’s spay status.

Ovariectomy

In much of Europe, ovariectomy is the preferred sterilization technique.  In this procedure, both ovaries are removed through a smaller incision in the flank or midline abdomen.  The uterus is left in place.  Because the ovaries (and therefore the source of reproductive hormones) are gone, heat behaviour is eliminated.  Additionally, pyometra can no longer develop because of the absence of progesterone.  A very small chance remains that uterine cancer could develop; however, this condition is rare in dogs. Although many families view a smaller incision a benefit of this procedure, improved patient comfort has been disputed.  Unfortunately, ovariectomy may have to be converted to ovariohysterectomy mid-procedure if uterine pathology is suspected, or if complications such as bleeding arise.

Laparoscopic Ovariectomy (Laparoscopic Spay)

Gaining in popularity is the laparoscopic spay.  At clinics equipped with a surgical endoscope, minimally invasive sterilization can be offered to pet owners.  During a laparoscopic spay, two small incisions are made in the abdominal wall to allow a camera and a surgical instrument to be inserted.  The abdomen is inflated with carbon dioxide to allow visualization and navigation.  The surgical instrument cuts and cauterizes tissue within the abdomen, allowing the ovaries to be removed without the surgeon’s hands entering the body.  The uterus is left in place in this procedure.  Benefits of this technique include reduced infection risk, smaller/aesthetic incisions, and improved comfort.  Again, complications may arise that mean a laparoscopic procedure must be converted to a conventional open surgery.  Drawbacks of this procedure include increased cost, and limited availability.

Ovary-Sparing Spay

There are some benefits to allowing a dog to live its life under normal hormonal influence.  The risks of certain orthopedic diseases, as well as incontinence and obesity are lower in intact females.  For this reason, families may inquire about sterilization techniques that preserve the ovaries.  In an ovary-sparing spay, the ovaries are left intact, but the uterus and cervix are removed, therefore preventing pregnancy.  Growth and development can proceed more naturally.  It is important for pet owners to know that the bitch will still exhibit behavioural signs of heat, and attract the attention of males.  Unfortunately, male mounting and penetration poses a serious trauma risk once the cervix has been removed.  Male/female interaction during estrus must be prevented for the safety of both animals. Mammary cancer risk is not reduced by this procedure. 

Neuter (Surgical Sterilization of the Dog)

Pre-scrotal Castration

The most common sterilization technique in the dog is pre-scrotal castration.  In this procedure, both testes are removed through a single incision over the base of the penis, leaving the delicate scrotal skin intact.  In most instances, the scrotal skin shrinks in the weeks after the procedure, leading to an aesthetic appearance. The benefits of this procedure include reduced mounting and wandering behaviour, reduce male-male aggression, and a lower risk of prostatic disease.  It is a relatively fast procedure, with a small incision and minimal pain when managed appropriately.

Scrotal Ablation

When there is some pathology on the scrotal skin, the redundant tissue can also be excised as part of the castration procedure.  Some pet owners request this for aesthetics, fearing an unsightly appearance of the empty scrotum after the neuter.  Because the tissue shrinks, this step is rarely necessary. Suturing the scrotal skin increases the risk of infection, pain, and poor healing, and should only be performed when medically necessary.

Prosthetics

Some families want the benefits of a sterilized dog, but the appearance of an intact one.  For this reason, the testes can be replaced with prosthetic devices called “Neuticles.”  Prosthetic testes have no health benefits, and may be controversial in the showing community.

Vasectomy

Testosterone is important for normal skeletal and muscular development. Vasectomy is a technique that maintains the normal hormonal environment of an intact male dog, while achieving sterility.  This protocol involves surgical ligation or transection of the ductus deferens, which conveys sperm from the testes to the urethra for expulsion.  Compared to juvenile castration, this technique reduces the risk of certain orthopedic diseases, and maintains the masculine appearance. It may be a good option for giant-breed dogs, and working dogs with androgen-driven motivation.  Unfortunately, unwanted hormone-linked behaviours and the risk of prostatic disease are not reduced by this option.  There is a risk of complications such as the development of a sperm granuloma, or re-canalization (healing and restored fertility).

Making Decisions

The veterinary community is still learning about the long-term positive and negative health effects of canine sterilization.  Population control and responsible breeding remain important factors in decision-making.  The sterilization technique, and the age of sterilization can have significant impacts on health and behavioural outcomes.  The ideal technique depends on the animal’s age, breed, purpose, and lifestyle.  A veterinarian should be consulted to discuss the right path for each patient.