spay and neuter cartoon by glasbergen



At the Animal Clinic at Thorndale, we know making the decision  about whether and when to spay and neuter your pet is a very important one. We recommend that all pets not intentionally destined for a breeding program be spayed or neutered at about 6 months of age. As soon as your new pet first arrives in your home, it is the time to start discussing this among family members. Older female dogs and cats that were not spayed prior to their first estrus (heat) cycle are more predisposed to develop breast cancer. Uterine infections, which can potentially be fatal, can also develop in older unspayed dogs and cats. Neutering males helps prevent medical problems such as prostate gland enlargement and curtails behavioral problems such as urine marking. Of course, a spayed or neutered pet cannot add to the overabundance of unwanted pets that sadly wind up on the streets, struggling to survive, or in shelters, competing with so many other homeless pets, to find their forever homes.

There is new information about  the health effects of spaying and neutering certain breeds of dogs earlier or later than 6 months of age. Please be aware that our doctors are following this information very carefully.  To date, studies suggest that each breed appears to be unique in how they respond to the age of spaying or neutering. Some problems common to specific breeds may occur more or less frequently when shifting the spay/neuter age.  Please ask us about any concerns you have about the appropriate  age for your pet's surgery.

Ovariohysterectomy and Castration- What do these terms mean?

The gonads are the organs in the body that produce the reproductive hormones, eggs and sperm. Technically, the terms neutering and gonadectomy can apply to the removal of the ovaries (female) or testes (male).  The term "castration" is specific to the male, and means removal of the testicles (also including their associated epididymis and a part of their vas deferens).  A "spay" applies to the female.

A spay typically means that both ovaries, the oviducts (fallopian tubes) and uterine horns down to the uterine body just above the cervix, are completely removed.  The technical term is an ovariohysterectomy.  Despite common belief that this is an easy ordinary procedure, one should think about the equivalent procedure in humans to understand its significance. A spay is a major abdominal surgery for your pet and should be treated as such.

Castration involves removal of the testes, epididymis and a portion of the vas deferens. Generally these organs are located outside the body cavity, and can be removed through a scrotal or pre-scrotal incision. In some cases, where the testes failed to descend into the scrotal sac properly, they may actually still be inside the abdomen.  The patients with undescended testicles are called cryptorchid (both testicles retained inside the abdomen) or hemicryptorichid (one testicle inside the abdomen and one in the scrotal sac where it belongs).  These patients should be neutered because the retained testicles have a higher rate of developing tumors as the pet grows older. Surgery on a cryptorchid or hemicryptorchid male is a major abdominal procedure.

What Happens in Surgery?

All patients undergoing surgery at the Animal Clinic at Thorndale will have a pre-anesthetic examination and blood work.  Depending on the age and health of the patient, we offer several levels of pre-anesthestic blood testing. If there are any concerns about your pet's health identified during the examination or blood tests, we will call and discuss these issues prior to proceeding.  It is important that the owner be accessible by telephone throughout the day when their pets are in our hospital. We want to be able to communicate concerns and progress in a timely manner.  If your pet is healthy, he or she will be given a pre-operative sedative.  An intravenous catheter will be placed.  This not only allows us to administer intravenous fluids throughout the surgery, but also gives us direct access to the patient's cardiovascular system during the procedure and during recovery. This is an extremely important measure we take with all of our surgical patients even during short procedures requiring sedation or general anesthesia. Our operating room is used exclusively for surgery and kept extremely clean. Surgical drapes, instruments, gowns, scrub brushes, hand towels, and other surgical accessories are all thoroughly cleaned and autoclaved (sterilized) for each patient.

Once a surgical level of anesthesia is induced, in most cases by injectable anesthetics,  an endotracheal tube placed.  This is a tube that goes through the patients mouth into the trachea, the main air passage into the lungs.  This allows us access to the patient's respiratory system, not only to administer gas anesthetics and oxygen, but also to control the patient's breathing if needed, and in some cases administer drugs directly into the airway. Again, this is important for your pet's safety and allows us to maintain an appropriate anesthetic level.

Once the patient is stabilized under anesthesia, he/she is surgically prepared by our board certified veterinary technicians while the veterinarian "scrubs in".  Surgical preparation includes clipping the hair from the surgical field and scrubbing the area to be absolutely certain it is clean prior to surgery.  During this initial phase, and from this point forward during the procedure, your pet will be carefully monitored.  Our hospital will follow your pet's heart and respiratory rates, pulse strength and rate, depth of anesthesia, electrocardiogram, temperature, blood pressure, oxygen content in the blood (pulse oximetry) and carbon dioxide level in their expired air. All that "beeping" equipment that is used in a human hospital is also connected to and carefully monitored while your pet is in our care.  We believe your pet is an important family member and will care for them as though they were one of our own.

Once the patient is prepared, the surgeon, wearing sterile gloves and typical surgeon's garb, will be presented with a sterile surgical drape and sterile surgical instruments. The surgical procedures involve an incision to access the reproductive organs to be removed.  It is very important for owners to understand that the length of an incision does not affect healing time.  Incisions heal edge to edge, not by length. Occasionally an incision will need to be made longer by a surgeon to gain access to unusually placed organs or to control any bleeding.

During abdominal surgeries, access is generally made through the midline of the patient.  There is a strong connective tissue line running stem to stern in all of us called the "linea alba" or white line.  Generally there is less bleeding along this entry line and also it is a very strong layer to close with internal sutures once the procedure is concluding. Once the surgeon has gained access to the abdomen, the reproductive organs are located, and the blood supply to those organs to be removed is ligated (tied off with suture material). The organs are carefully removed and the patient checked repeatedly for any bleeding prior to closing the incision.

Castration Procedure

For castrations, the incisions are either made through the scrotal sac or through the skin along the midline just in front of the scrotum on the abdominal wall (pre-scrotal).  With testicles in the proper position, only more superficial layers surrounding the testicles (tunica vaginalis, being the proper term) are incised to expose the testicle, epididymis, vas deferens, spermatic cord (blood supply).  The abdomen is not entered so the procedure and recovery are easier for the surgeon and patient. Once the testicle has been exposed, the surgeon will clamp off and then ligate the spermatic cord.  This cord contains the main testicular artery going to the testicle and the network of veins leaving  the testicle. This network of vessels serves as a counter-current heat exchanger, similar to a car radiator, to keep the testicular temperature lower than the internal body temperature.  Sperm production requires a slightly lower temperature.  The testicles of cryptorchid animals are generally unable to produce sperm due to the higher temperatures in the body, although hormone production is normal in these retained testicles. In dogs with scrotally placed testicles, there is generally a substantial muscle, the creamaster,  that allows the body to pull the testicles closer in for warmth during colder weather.  This muscle is also often ligated during castration.  If a scrotal approach was used, as commonly done in cats, there are generally no external sutures placed in the scrotal sac. The internal sutures will eventually dissolve after the blood vessels have permanently sealed. In a pre-scrotal approach, primarily used in dogs and rabbits, when the incision is small, the sutures may be all buried under the skin.  Sometimes a small amount of surgical tissue glue is used on the surface to cover the wound and keep the skin edges neatly together.  If skin sutures are used, they generally need to be removed in 10-14 days after surgery.

Ovariohysterectomy and Cryptorchid Castration are Major Abdominal Surgeries

During a spay, it is important to consider the complexity of the procedure.  There is a blood supply to each of the ovaries that comes directly off the aorta.  The uterus is fed by a two directional supply, at the top by this ovarian artery and at the cervical end by a uterine artery.  All these vessels must be accounted for and securely ligated.  The ovaries themselves lie very close to the back body wall, up near the rib cage, and both ovaries and uterus are attached by firm ligaments which give them support, especially during the downward weight applied during a pregnancy.  Unlike in humans, the uterus in our patients consists of two long tubes, each running from the upper abdominal back body wall, where the respective right and left ovaries are located, all the way down to the pubic inlet where the cervix is located.  Our patients have litters, not single young, so the long tubular uterine horns give a place to safely grow all those puppies and kittens (or bunnies or rodents).  During their pregnancies, the fetuses appear as multiple "lumps" along each of these uterine horns. During an ovariohysterectomy, the ligaments supporting the ovaries and uterus must also be broken and assessed for any bleeding.  Obese patients are challenging because there is a lot of abdominal fat to wade through to access these organs.  Females in estrus (heat) will have an enlarged reproductive tract with an exuberant blood supply, awaiting a potential pregnancy.  Generally this is not a problem in cats, but especially in large dogs, it creates a greater surgical risk.  We recommend that dogs in estrus have their surgery delayed until 4 months after the heat cycle, so their reproductive organs will be in a quiet phase.

Similarly, when the surgeon is retrieving a cryptorchid  testicle trapped in the abdomen, the incision will generally be made through the linea alba.  Of course, in the male, it is necessary to push the overlying penis and prepuce aside to gain midline access. The retained testicle is located by following its attachment to the urinary outflow system backwards.  The sperm produced by a testicle travel through the vas deferens, to connect to the beginning of the urethra below the neck of the bladder.  By locating the bladder, finding the vas deferens of the "missing" testicle, the surgeon then traces the vas deferens backward to the testicle.  This could be anywhere along its normal embryonic journey. The retained testicle could be anywhere, high up near the ribs against the back body wall,  inside the middle of the abdomen or out in the inguinal ring. The inguinal ring is the opening at the inner thigh through which the blood vessels to the hind leg emerge as well as the blood supply and vas deferens of a normal testicle. The latter emerge through this opening on their way to the scrotal sac.  Because it is attached to the vas deferens, the retained testicle can be always located by following the trail backwards from the neck of the bladder. Once the testicle is found, its blood supply, attachments, and vas deferens are ligated, and the testicle removed from the abdomen. While this is not a "hunt and peck" surgery for the missing organ, it is time consuming to move internal organs around to trace the vas deferens. Sometimes the position of the testicle in the abdomen can make it difficult to elevate it into the surgical field for removal. This is a major abdominal surgery.

Fortunately for many cryptorchid dogs, the "retained" testicle is not truly in the abdomen, but has escaped through the inguinal ring and is located somewhere on its journey outside the body to its proper home in the scrotal sac. Sometimes these can be felt, or palpated, while the dog is awake and bouncing around on the exam table; other times they may be so small that they can only be felt when the dog is under general anesthesia on its back on the surgery table.  They are then generally located in a fat pad adjacent to the exterior of the inguinal ring.  Ones that can be identified by careful palpation can sometimes be pushed down into the pre-scrotal incision and removed with the other testicle.  Sometimes a separate incision is made through the skin and tunica vaginalis to extract the partially retained testicle closer to the inguinal ring.  Other times this testicle is so small that it cannot be felt inside the fat pad.  In this case, the surgeon will need to go in abdominally to locate the vas deferens and trace it back to the hidden testicle.  By gently tugging on the vas deferens, the surgeon will be able to see the testicle move under the skin near the external inguinal ring and retrieve it.  At this point, the patient has had an abdominal surgery and recovery will be slower. During a castration, the retained testicle MUST be removed. Remember this is a potential tumor site later in life.  If for some reason your veterinarian is uncomfortable retrieving a retained testicle, please call our doctors so it can be take care of properly.

All abdominal surgeries are generally closed with three layers of suture.  The deepest layer is the linea alba. The second layer is a tough connective tissue just below the skin's surface, the subcuticular layer, and the outermost layer is the skin.  In most cases, skin sutures, or staples if used, need to be removed in 10-14 days.

Pain Management

All patients deserve to be comfortable before, during and after their surgery.  Our hospital will always provide the proper analgesics for your pet while in our care.  We will also be sending home additional pain relief medications for you to administer to your pet once they are home. If you find that your pet is still uncomfortable during or after completing its course of medication, please call us and we will dispense additional medication or prescribe it for a longer time period.

Because certain pain medications can interact with each other and other drugs, it is very important that you inform us of any medications and supplements your pet has taken for the 10 days preceding their surgery.  If they take medication routinely, please inform us ahead of time so we can discuss any adjustments that might need to be made prior to surgery.

Post Operative Care for Spay and Neuter Procedures

As described above, your pet will go home with analgesic medication to keep them comfortable after their surgery.  Please read these directions carefully and do not overdose the medication.  If your pet seems uncomfortable, even with the dispensed medication given, call us and we may add on additional medications.  Each patient is unique. Most pets will be able to eat their normal diet for dinner after their return home.  We do recommend that you cut back on the portion of food because they have had an anesthetic and surgical procedure.  The day after they are home they can resume their normal eating habits. We may send home an Elizabethan collar to prevent your pet from chewing or licking at the incision. Again, each pet is unique.  Most will not bother their incision, while others can be obsessed with licking or chewing it.  If you prefer not to use the collar, certainly an abdominal wrap, such as an Ace bandage, may help protect an abdominal incision from your pet's licking. For male dogs, putting them in boy's underwear, worn upside down so the tail can wag out the fly opening may be sufficient. Don't forget to use something colorful and take photos! If the incision line has any odor or unusual discharge, schedule a recheck.  Licking a surgical incision with a dirty tongue is often the cause of a post-operative infection.  In these cases, antibiotics will be needed.

The most important aspect of post operative care during this recovery period is the restriction of activity for 10 to 14 days.  At the end of this time period, the skin sutures, if present, will be removed. It is imperative to confine cats so they are not leaping tall buildings with single bounds. Dogs must be leash walked to go out to the bathroom and immediately back into the house.  If your dog is excessively active in the house, it may need to be crated.  The sutures are holding the internal layers together so the body can grow new tissue across the incision line and heal.

Swelling along the incision line may occur.  Any excessive stress on the sutures may cause them to break and a hernia may result.  This will look like a swelling below the skin suture line that when pressed upon, will pop its contents back into the body cavity through the hole left by the missing sutures. Another more common type of swelling along the suture line is called a seroma.  This is a fluid filled, generally firmer swelling that cannot be "reduced" into the body cavity.  It does not disappear when you press on it.  Seromas most commonly develop when the pet is too active after surgery.  The layers closed with suture material are rubbing against one another as your pet wriggles around.  The irritation to the tissues results in an excess production of fluid.  Seromas will resorb on their own over time and the surgery area will go back to being flat.  Occasionally the seroma may drain through a small gap in the skin sutures.  While this is not harmful, it should be checked, and wrapped if the drainage is excessive.  If your pet develops a swelling along its incision line, schedule a post-operative recheck in our hospital.

Occasional patients will need sedation during the recovery period. Please let us know if you are having difficulty curbing your pet's energy.

Please keep in mind that you are in charge of your pet's post operative home care period. We are here to help you if any problems should occur.  We certainly want our surgeries to have a complete and successful recovery.

If you have any questions or would like to schedule a spay or neuter procedure for your pet, please call our hospital at 610-873-4091.  Our hospital staff and veterinarians are available to assist you.