Lessons learned about safe, efficient spays and neuters
Having just graduated from veterinary school two years ago, I thought I was pretty up-to-date on spay and neuter techniques, but I learned I couldn’t have been more wrong when I attended a session at CVC Kansas City on efficient spay neuter techniques and the updated spay and neuter guidelines by Philip Bushby, DVM, MS, DACVS. He started out his series of tips and tricks all practitioners might gain from examining the high-volume spay and neuter clinic guidelines by asking us, “What’s the most expensive thing you use when you perform a spay or neuter?” The answer: your time. Dr. Bushby says being more efficient is a combination of many things put together—the sum of its parts are greater than the whole.
And it’s not just about efficiency. Dr. Bushby says a goal in performing a spay or neuter is to be minimally invasive—not in the sense of the need for fancy equipment. He says minimally invasive surgeries refer to surgical techniques that limit the size of incisions needed, which reduces postoperative pain and decreases surgical time and, in turn, decreases surgical and anesthetic complications. You just have to place your incisions in the right places.
Another key point is to question the reason you do things the way you do them. Surgical techniques used in high-volume spay and neuter clinics are efficient and safe but are fundamentally different from those taught in veterinary school, Dr. Bushby says. In veterinary school, students are taught to double ligate everything. What’s the point of double ligating if the first knot was secure in the first place? It’s to compensate for lack of student skill or knowledge in the initial states of surgical training.
With these thoughts in mind, let’s take these surgeries one step at a time.
Properly positioning the patient
How you position the patient on the table matters. The best method is to tie the patient’s arms to its sides via a string behind its back (Editors' note: See an alternative for this positioning here). This method helps the animal to relax its abdomen, Dr. Bushby says. Crossing the arms over the chest is OK, if not tied too tightly.
For feline castration, place the cat on its back and tie the legs up pulled forward. Quick tip: The new guidelines say it is OK not to drape for neuters and to use exam gloves instead of surgical.
Cutting in just the right spot
The placements of your incisions can make your job easier and faster, Dr. Bushby says.
Spays. In a feline spay, cut in at the midpoint between the umbilicus and anterior brim of the pubis because the uterus is most difficult to exteriorize in cats. The puppy spay incision site at ventral midline is just a bit more cranial than a cat spay incision site. In an adult dog, the ovaries are more difficult to remove, so your incision should be more cranial than in a puppy.
Feeling brave? Dr. Bushby uses a ventral midline skin incision but then enters the abdominal cavity slightly right paramedian. This equalizes the difficulty of exteriorizing the two ovaries. He does this by undermining the tissue to the right of the linea alba. How far right do you go? Dr. Bushby says about 2 cm in a giant breed and maybe 0.5 cm in a small Yorkie. If you go too far, the right ovary pops out and you can't get to the left ovary.
Dr. Bushby says most people don't put enough pressure at first when cutting through the fascia on the paramedian side. Once you’re through the fascia, poke through the muscle fibers with hemostats. Don’t cut the muscle fibers because they will bleed. Instead, bluntly separate muscle fibers, pick up the peritoneum and cut through it and, voila, you are in the abdomen.
Another reason this paramedian approach is nice is that the falciform ligament is very vascular and bleeds heavily. You usually have to deal with the falciform ligament when you drop a pedicle and you need to extend your midline incision. When you extend your incision beyond the falcifom ligment attachment, however, you have a greater risk of dehiscence because the falciform ligament will try to push up into your incision site when closing. Offset closures might also be more secure, says Dr. Bushby.
Neuters. Dr. Bushby performs all of his castrations through a scrotal incision instead of a prescrotal incision. Research shows that the incidences of swelling, hemorrhage and pain with scrotal castrations are no different than with prescrotal, but the incidence of self-trauma is lessened with scrotal incisions, and it takes less time. Just make sure you don’t place external skin sutures in the scrotal skin.
For an adult dog castration, Dr. Bushby uses scrotal incisions and then ligates—whether you use clamps or not is up to you. The piece that saves you time is the closure. One technique is to not close the incision, but then you need to communicate to the client that the surgical site will drain for two or three days after surgery. You can oppose wound edges, evert them slightly and glue them, or you can place one buried subcutaneous suture in the center of the incision, but again there will be drainage so client communication will be important, says Dr. Bushby. If you want the patient to self-mutilate, put sutures in the scrotum or clipper burn the scrotum. The lesson: It's OK to have stubble, he says. Don't clip too close.
Getting to the goods
Dr. Bushby theorizes that it’s less painful to cut the suspensory ligaments, but there are no studies yet to prove this. But with properly placed incisions he can visualize the ovary and associated vessels easily and cut the suspensory ligament. Dr. Bushby places a hemostat on the proper ligament, applies upward tension, and then visualizes and cuts the suspensory ligament.
Tying the knots
If you know how to do hand ties, use them, says Dr. Bushby. It's faster because you don't have to pick up and put down instruments. You can use the pedicle tie in any cat spay, he says, but do not use it in a dog since the fat prevents you from isolating the vessels.
Dr. Bushby has one caution with the pedicle tie in cat spays—there is a tiny capillary on the ovarian pedicle that you have to sacrifice in order to completely cut through the suspensory ligament and exteriorize the ovary well enough to do the tie. When you tie the knot, you've tied the vessels. No suture material is needed and it's faster. Note from Dr. Bushby: People often give up on the pedicle tie if they can't get enough exposure. This is simply from failure to fully cut the suspensory ligament.
To close the linea alba, use a continuous or cruciate pattern. Remember there is a big difference between ligating and suturing—with one you crush the blood supply and with the other you preserve blood supply and bring the tissue into apposition, Dr. Bushby says. He does the linea alba closure and then immediately goes into the subcutaneous and subcuticular closure finally tying onto the initial cruciate tie with a minimum of four throws.
Dr. Bushby ligates uterine bodies using a Miller’s knot. To create a Miller’s knot, pass the suture under the uterine body and then under again, creating a loop. Pass a needle holder through the loop and tie a regular square knot. When you tighten the square knot, the loop collapses onto the knot holding it secure. Finish with three or four additional square knot throws. Dr. Bushby has a video on this technique available here: http://mymedia.msstate.edu/outputset.php?id=25524.