Preventing and managing spay/neuter complications (Proceedings)
Surgical complications are always a possibility in spay/neuter surgeries, but certain practices can help minimize problems. Obviously, prevention of complications is the best approach, but early recognition of problems and effective management of problems are the keys to ensuring excellent patient care and successful recovery from surgery. The most common complication are hemorrhage, pain, swelling, and surgical dehiscence. Ovarian remnants while not common are serious and must be addressed.
Hemorrhage can occur from many different sources during an ovariohysterectomy. Subcutaneous tissue, rectus abdominis muscle (if you cut muscle fibers), ovarian pedicles, uterine vessels, broad ligament and, unfortunately, from structures that should not even be involved in a spay (spleen, mesentery, bladder). Obviously, prevention of hemorrhage is much better than control of hemorrhage once it has occurred. To avoid inadvertent trauma to abdominal organs while entering the abdomen of the cat, the puppy and the adult dogs (if you do midline approaches in the adult dog) elevate the linea alba, hold the scalpel parallel to the abdominal wall with the sharp edge of the scalpel blade facing up. Plunge the scalpel into the linea and lift up. This approach avoids any downward movement of the scalpel that could inadvertently incise the spleen, intestine, mesentery or urinary bladder. If you do paramedian approaches in adult canine spays, after separating the fibers of the rectus abdominis muscle elevate the peritoneum before cutting with scissors. Again, this technique prevents inadvertent trauma to abdominal organs.Splenic lacerations caused by too aggressive abdominal entry can be managed by carefully suturing the splenic capsule using 3-0 or 4-0 absorbable sutures with a taper needle in a simple continuous pattern. The splenic wound is then covered with absorbable hemostatic sponge. When suturing the capsule extreme care must be taken to prevent making the splenic laceration worse. The splenic capsule, is easily torn so you must be very careful when placing sutures.
Bladder lacerations caused by aggressive abdominal entry can be managed by suturing the bladder wall with 3-0 absorbable sutures in a simple interrupted or simple continuous pattern.
Mesenteric lacerations that involve mesenteric vessels are managed by ligating the damaged vessel(s) and suturing the tear in the mesentery with 3-0 absorbable suture in a continuous pattern. If you ligate one or more mesenteric vessels you must check the color of the involved intestines prior to abdominal closure to make sure the intestine remains viable. Loss of intestinal viability will necessitate an intestinal resection and anastomosis.
To prevent hemorrhage from the ovarian pedicles in the dog, I recommend a single ligature placed securely. The critical factor here is making sure that the ligature is several millimeters away from any crushing instrument (hemostat or carmalt). Use a three-clamp technique placing the first hemostat (or carmalt) most proximally and only closing it 1 click of the ratchet. Place the second hemostat several millimeters distal to the first allowing enough separation that the ligature will crush the pedicle completely ligating the ovarian vessels. A third hemostat is placed between the ovary and the uterine horn. The single ligature is controversial, but one tight secure ligature is all that is needed. Ligatures can be tied with a square knot, a surgeon's, knot or a Miller's knot depending on the amount of tissue that is to be incorporated into the ligature. Of these, the Miller's knot is the most secure.
A similar technique is used on the uterine stump, ligating the uterine vessels. Depending on the size of the uterus and the uterine vessels, this ligature may be supplemented with either a transfixation ligature or separate ligatures around each uterine vessel or both. When the patient is in estrus and the uterus is turgid it is advisable to ligate without placing any hemostatic clamps on the tissue.
If an ovarian pedicle tears, retracting back into the abdominal cavity prior to ligation, you must retrieve and ligate the pedicle. Using the "biological retractors" improves your ability to find the bleeding pedicle. If the right ovarian pedicle is bleeding find the descending duodenum and reflect it to the left exposing the caudal pole of the right kidney and the right ovarian pedicle. If the left ovarian pedicle is bleeding find the descending colon, reflect it to the right exposing the caudal pole of the left kidney and the left ovarian pedicle. The safest way to exteriorize a bleeding ovarian pedicle is to reach in with two fingers, grasp the pedicle and exteriorize it. Once the pedicle is exteriorized you can place two hemostats and ligate in the crushed area of the most proximal hemostat. Remember the ureters are just deep to the ovarian pedicles so reaching in and clamping a bleeding ovarian pedicle with a hemostat can cause injury or result in ligation of the ureter.
Prevent hemorrhage from the broad ligament by carefully evaluating the size of any vessels in the broad ligament prior to incising or tearing the broad ligament. Any vessels of substantial size should be ligated prior to cutting / tearing the broad ligament.
Ligation of the spermatic cord in the puppy or the cat is performed using a figure eight knot in the cord. Ligation of the spermatic cord in the adult dog is by use of the Miller's knot. In dogs over 18 kgs I generally place a transfixation ligature just distal to the Miller's knot.
Hemorrhage from a castration is generally due to insecure ligatures. The Miller's knot is an excellent knot for the ligation of the spermatic cord in adult dogs. I recommend the placement of one ligature using a Miller's knot on the spermatic cord of the adult dog if the dog weighs over 18 kgs (40 lbs). In dogs greater than 18 kgs place a ligature with a Miller's knot proximally and a transfixation ligature distally.