Chapter 53 Richard M. Hopper Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Starkville, Mississippi, USA For cows of genetic merit or perceived to be of high value, urogenital procedures are typically performed with the goal of restoring fertility. However, a desire to extend the life of the cow so that a calf can be reared, a lactation completed, or simply to add condition prior to sale often justifies attempts at surgical correction as well. The procedures that will be described can be performed on the standing animal with regional analgesia and sedation. Parturition is clearly one of the most dangerous events in the life of an animal, whether the dam or the offspring. Common injuries include trauma and tears of the uterus and caudal urogenital system. Tearing of the uterus, whether spontaneous or iatrogenic, can be life-threatening. At the very least, the resultant fibrosis and structural incompetence from perineal body, cervical, and vaginal tears typically results in infertility. Identification of the severity and the provision of a realistic prognosis are critical to the producer, so that an informed decision can be made with respect to treatment versus culling or even immediate salvage. Most injures to the uterus are iatrogenic and occur during efforts to relieve dystocia. With few exceptions they occur on the dorsal aspect of the uterus (cranial to the cervix) when the obstetrician is attempting to repel a breech presentation or during the forced extraction of a large fetus. In the first case, repair is secondary to removal of the calf. If a cesarean section is performed, the uterine defect may be approached and repaired after the calf is delivered. This is almost always the case when dealing with a tear that occurred during repulsion of a breech position fetus. If the calf can be delivered vaginally following this type of tear or, as in the second case, in which the tear occurs during the delivery, a “blind” suture repair through the vagina can be performed. I will first examine how these tears occur. In the case of the tear caused by “excessive” force in the obstetrician’s attempt to repel the calf, the uterine wall was probably weakened by some level of pressure (ischemic) necrosis. This occurs when the tailhead of the fetus in the breech position is pressed for hours against the dorsal uterine wall. In the second situation, a large calf, a “dry” birth canal, and forced extraction combine to create an overfolding and subsequent shearing of the uterine wall. These tears are usually 5–30 cm in length, although some seem almost circumferential. Regardless of the tear’s etiology, repair may not be necessary if it is small and dorsal. Because of rapid uterine involution, tears smaller than the width of a hand will usually be satisfactory without repair. Treatment for these can be limited to repeated oxytocin injections for the first 24–48 hours and 7–10 days of antibiotics. If the tear is larger, it can be closed with a “blind” suture technique.1 To perform a one-handed blind closure of a uterine rent, first thread an atraumatic needle (size and shape determined by preference) with a 150 cm of #2 or #3 catgut. With the needle at the halfway point of the suture (doubled), make a knot at the end (knot 1) and about 25 cm from the end (knot 2). Next introduce the needle into and through the vagina, guarding the point with the fingers until the tear is reached. Begin closure at one end of the tear. After piercing the uterine wall (about 1 cm lateral to the tear) run the needle between the doubled suture and cinch at knot 2 (the only purpose of knot 1 is to keep the two loose ends together). Then close the tear with a continuous pattern until the last bite is made 1 cm lateral to the other end. It is important to pull the suture tight with each throw. Then reverse and continue the closure back to the original site and tie to the suture tail. Uterine involution serves to cover small appositional problems. Recommended treatment includes antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and oxytocin (Figures 53.1, 53.2, 53.3 and 53.4). Figure 53.1 With the suture “doubled” the first bite is made at the lateral edge of the wound most easily accessed. Figure 53.2 After the first suture bite is taken, pull the needle through the loop created in the suture (this is not a knot, the suture is cinched). Figure 53.3 Continuous suture bites. Figure 53.4 After reaching the end of the wound, return. This would look similar to a cruciate pattern and serves to correct the appositional deficiencies of the first row of sutures. When the pattern is complete, the suture is tied to the “tail.” Alternatively, the uterus can be prolapsed to facilitate suture repair. To prolapse a uterus, the cervix must still be completely dilated. Therefore this procedure must be performed within 6–12 hours of parturition. Administer 10 mL of 1 in 1000 epinephrine in 250–500 mL of saline intravenously very slowly. Do not perform an epidural or administer oxytocin. The cow must be able to strain and the uterus must be flaccid. If possible, an assistant should administer the epinephrine solution, so that the surgeon is free to perform the procedure. As the solution is administered, enter the vagina with an arm, reaching as far cranial as possible to grasp a placentome and pull slowly. This will invert the tip of a uterine horn and the presence of the arm along with the invaginated uterus will stimulate straining. Pull with the cow’s straining, grasping other placetomes if necessary. The uterus will usually come out within minutes. At this time if the rent or tear can be visualized, it can easily be repaired. The uterus is then cleansed and replaced. It should be noted that this procedure has limited application in that many of the iatrogenic tears encountered as a result of, or during the management of, dystocia are very close to the cervix; thus after the uterus is prolapsed, the area of the tear will usually still be within the vagina, so not allowing the accessibility desired. Additionally, many of these tears can be near circumferential, and manual prolapse may be synonymous with uterine extraction – because the uterus is held in place with only a small amount of tissue, upon prolapse it simply tears and falls off. Thus careful evaluation of the tear and its location and severity is warranted prior to prolapse for repair. As with the “blind suture” repair, antibiotics, NSAIDS, and oxytocin should be given postoperatively. Occasionally a cow will present two or more days following parturition with signs of peritonitis, depression, and anorexia. The cow may or may not have a history of obstetric intervention or even suspected dystocia. Examination may reveal a distal uterine tear which is likely the result of a spontaneous tear or, of course, an injury similar to the iatrogenic injury previously described. Additionally, the peritonitis could be a complication following cesarean section. In any case because of the duration of injury and peritonitis, surgical exploration of the abdomen via a flank approach should be performed. Treatment of the peritonitis begins with thorough abdominal lavage, which in turn is facilitated by the ventral placement of a drain. Utilization of a rumen trocar placed from within the abdominal cavity at the ventralmost aspect will provide very efficient egress for the volume of fluid that is required (Figures 53.5 and 53.6). Additionally, because of the “siphon” effect that is created, debris (fibrin clots, necrotic material, and placental remnants) will be “pulled” to the drainage site and can be more efficiently retrieved. The rent in the uterus can then be repaired, the uterus lavaged, and finally the flank incision closed. This of course is accompanied by a guarded prognosis, so this level of effort is typically reserved for the cow of genetic merit or the involvement of a highly motivated owner. Figure 53.5 A rumen trocar placed from within the abdomen and directed outward at the ventralmost location. Figure 53.6 Fluid flow through the trocar cannula from the abdominal lavage. Tearing of the vulva, vagina, and cervix occur almost exclusively during dystocia. Tearing and bruising can often occur during parturition in the absence of obstetric intervention; however injury to these structures typically occurs during obstetric management of dystocia. Tearing of the vulva during the management of a dystocia can be prevented by performing an episiotomy. This procedure is discussed in Chapter 46, but briefly it is an incision typically made at the dorsolateral (10 o’clock or 2 o’clock) aspect of the vulva. This incision will serve to either avoid or, at the very least, “guide” the tearing that occurs with the extreme stretching of the vulva during a dystocia due to an oversized fetus. If an episiotomy is not performed, the tear will most likely occur at the most dorsal aspect of the vulva toward the anus and this in fact is the mechanism for grade 1, 2, and 3 perineal lacerations, a grade 3 being a rectovaginal tear. Lacerations that involve only the vulva and even episiotomy incisions can be left unrepaired especially if the cow is to be culled. However, this often results in compromised vulvar competence so these tears should be sutured immediately. A modified vertical mattress pattern can be used. Take a deep bite that includes the skin, fibrous tissue, and mucosal layers, and then the skin only for the superficial bite.2 Although nonabsorbable suture material is often recommended, #1 chromic gut can be used. Vaginal tearing usually occurs in overfit heifers during the forced extraction of a calf. In these heifers vaginal fat serves to decrease the cross-sectional area of the birth canal, thus serving as a contributing factor in the dystocia. During parturition, and specifically forced extraction, the vaginal wall will split allowing the protrusion of this fat. This fat can and should be removed, but suturing the laceration is neither necessary nor recommended.2
Surgery to Restore Fertility
Introduction
Repair of injuries occurring from dystocia
Repair of uterine tears
Injury to the vulva, vagina, and cervix
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