Ovariectomy and Ovariohysterectomy

Ovariectomy (OVX) and ovariohysterectomy (OHX) are done for the purpose of elimination of females from breeding programs, for elimination of undesirable genetics (poor textile traits, genetic defects), and because of acquired diseases. Acquired diseases of the ovary include ovarian teratoma, ovarian granulosa theca cell tumors, interstitial cell tumor, and ovarian or paraovarian cysts (Figure 62-1).^1,2 Diseases of the uterus may include segmental aplasia, chronic infection, and uterine neoplasia.³ OVX and OHX may be done via traditional laparotomy or by laparoscopy. Laparoscopy is the preferred technique for ovariectomy, especially unilateral OVX. Laparoscopic OHX is done infrequently. Laparotomy may be done for OVX or OHX and most often is accomplished with the camelid under general anesthesia. Unilateral OVX may be done via lateral abdominal (flank) laparotomy or caudal ventral midline laparotomy. Bilateral OVX and OHX are most easily done via caudal ventral midline laparotomy, with the patient under general anesthesia and placed in the Trendelenburg position (dorsal recumbency, head and neck tilted downward at a 30-degree declination).

The caudal ventral midline incision is begun at the umbilicus and extended caudally toward the brim of the pelvis. The incision is lengthened, as needed, to facilitate surgical exposure. The incision is made through skin, subcutaneous tissues, the linea alba, and the peritoneum. Care must be exercised to remain on the ventral midline because the linea alba is narrow. A No. 10 scalpel blade is used to divide a small (<3 cm) portion of the linea alba, taking care not to penetrate the peritoneum. Digital pressure is used to penetrate the peritoneum and explore the peritoneum and abdomen adjacent to the proposed incision line. Sharp dissection is used to lengthen the incision along the ventral midline by using either the surgeon’s fingers or an instrument such as tissue forceps to protect the viscera from trauma during dissection. Access to the pelvic inlet may be improved by elevating the surgical table to place the animal in the Trendelenburg position, with the pelvis elevated and the head and neck dependent. Balfour retractors also may be used to improve exposure of the uterus and ovaries. This is particularly useful in cases having segmental aplasia to minimize the risk of stump mucometra or pyometra after surgery.

Complications of OVX and OHX are similar to those of other abdominal surgeries and include incisional infection, adhesions, peritonitis, and incisional hernia.

Uterine Torsion

Birthing in llamas and alpacas is a rapid process. Studies in South America documented that greater than 80% of crias (neonatal llamas or alpacas) are born between 6 AM and 1 PM.¹ Stage II labor (expulsion of the cria) occurs over a period of 10 to 15 minutes (range 6–47 minutes).⁴ Dystocia is an uncommon event in llamas and alpacas. Studies in South America found that dystocia in alpacas (1660 birthings observed) occurred in 1.6% of birthings and that 25% of these occurred in primiparous females. Data in a smaller number of llamas (234 birthings observed) demonstrated dystocia in only 1 female (0.4%).⁴ Interestingly, causes of dystocia differ between South American and North American camelids. Uterine torsion is rarely found in descriptions of dystocia in South American camelid herds. Causes of dystocia in these populations include fetal malpositioning, with 30% of those occurring with the fetus in a posterior presentation and 70% in anterior presentation.⁴ Markedly less information is available documenting causes of dystocia in North American herds.^5,6 The available data seem to indicate that uterine torsion is a common cause for veterinary intervention of dystocia.^5,7 Our opinion is that fetal malpositioning is associated with the majority of dystocia in llamas and alpacas and that uterine torsion is overrepresented in the literature because these cases are more likely to be presented to teaching hospitals for treatment.⁶

Uterine torsion occurs when the pregnant uterine horn rotates around the long axis of the uterus and remains in that position. In nearly all cases of diagnosed uterine torsion, the veterinary examination of the female is performed because of abnormal dam behavior or clinical signs of abdominal pain noted by the owner. Uterine torsion was reported to account for 60% of dystocia cases presented to a veterinary teaching hospital and has been reported to cause 30% of dystocias in dromedary camels in another institution.5,8 It is likely that uterine torsion may occur and resolve without clinical signs being noted during early stages of pregnancy. As pregnancy advances, torsion of the uterus is less likely to self-correct. Therefore, females having clinical signs associated with uterine torsion should be treated as an emergency to save the viability of the fetus and the life of the dam. Delays in treatment may increase the risk of strangulation or rupture of the uterus and rupture of the uterine artery.

Most clinical cases of uterine torsion occur after the ninth month of pregnancy. Unlike horses and cattle, in which uterine torsion most often occurs at term, uterine torsion in alpacas and llamas frequently occurs 2 to 6 weeks before the due date for parturition. In a report of 20 uterine torsions in llamas and alpacas, 90% of the affected females were in greater than 335 days of pregnancy.⁵ When possible, we leave the fetus to continue to a natural birthing process (e.g., in females having a uterine torsion greater than 2 weeks before parturition and closed cervix). Poor survival of crias born after induction of parturition or premature birth has been reported.⁹ In that study, induction of parturition was attempted with fluprostenol, oxytocin, or three different dosages of dexamethasone. Alpacas given fluprostenol delivered live crias a mean of 21.5 hours after treatment. Oxytocin in combination with dexamethasone (0.05 milligram per kilogram (mg/kg)) failed to induce parturition. Dexamethasone at 0.5 mg/kg resulted in stillborn fetuses. Thus, neither oxytocin nor dexamethasone can be recommended for induction of parturition in alpacas. We routinely monitor fetal heart rate, placental thickness, and placental fluid echogenicity to assess fetal well-being. Cesarean section is performed if the fetus is determined to be at risk. Ultrasonographic monitoring of the fetus may include echotexture of the fluids within the heart and body cavities of the fetus. Evidence of impending fetal distress include decreasing heart rate, placental fluids developing a turbid appearance on ultrasonography, rapid changes in placental thickness, and apparent separation of the placenta from the endometrium.10,10a

Nonsurgical correction of uterine torsion requires accurate assessment of the direction of the torsion. Incorrect or lack of determination of the direction of torsion before rolling the dam may cause progression of the torsion and obstruction of arterial blood flow to the fetus and uterus. Uterine torsion occurs as either clockwise (torsion of the left horn to the right side) or counter-clockwise (torsion of the right horn to the left side) rotation. The clockwise or counter-clockwise direction of rotation is referenced by the observer standing behind the patient and looking at the rear of the female. The pregnant uterine horn moves around the long axis of the uterus similar to the direction of the rotation of the hands of a clock. When visualizing a clock face with the vulva at the center, the normal, nonpregnant uterine horns are positioned at the 3 o’clock (right horn) and 9 o’clock (left horn) positions. With advancing gestation, the pregnant horn gravitates ventrally and toward midline. This shift in position does not effect the orientation of the broad ligaments of the uterus which remain parallel coursing from their caudodorsal attachments towards a cranioventral position. The broad ligaments become thicker and more taut as the uterus become more dependent with the weight of the fetus and fluids. The caudal extent of uterine torsions is often anterior to the cervix. Thus, vaginal speculum examination may fail to diagnose the presence of a uterine torsion. At term, the presence of a torsion will interfere with cervical dilation. In a report of 20 occurrences of uterine torsions diagnosed in 11 llamas and 3 alpacas, 95% were in a clockwise direction.⁵ Counter-clockwise uterine torsion may be more common in alpacas than in llamas.¹⁰ These differences exemplify the need for accurate diagnosis of the direction of uterine torsion before attempting nonsurgical correction.

A variety of risk factors have been suggested as increasing the likelihood of uterine torsion including large birth weight, male gender, and maternal illness.¹¹ Environmental factors that affect dam behaviors may contribute to risk. Activities thought to increase the risk of torsion include rolling, right horn pregnancy, and prolonged duration of pregnancy.

Clinical signs may include lethargy, restlessness, reluctance to rise and remain standing, anorexia, tachycardia, tachypnea, rolling, kicking, vocalizing, abdominal compressions, and straining. Uterine torsion should be suspected when a dam is in late pregnancy and shows signs of abnormal behavior or labor without progression.

Accurate diagnosis and assessment of the direction of uterine torsion requires careful attention to vaginal speculum examination, transvaginal palpation, and rectal palpation. During vaginal speculum examination, the vestibule is inspected for deviations and compression. Rectal examination must be done carefully to prevent damage or perforation of the rectum.

Thorough palpation is required to idendify the broad ligaments which are normally thin, pliable, and ill-defined. Safety of rectal palpation can be improved by using restraint in a camelid chute, mild to moderate sedation, use of copious lubricant, and application of lidocaine jelly directly on the anal sphincter and in the rectal lumen. The direction of the uterine torsion is assessed by palpation of the course of each broad ligament. The broad ligament associated with the pregnant uterine horn will course from its caudal and dorsal attachment, crosses the pelvic canal dorsal to the uterine body, and then cranioventrally to the contralateral side of the abdomen. In contrast, the broad ligament associated with the nongravid horn courses from its attachment caudodorsally in the abdomen and continuing ventrally to the cervix and uterine body. This broad ligament cannot be palpated as it continues cranioventrally to the uterus in the abdomen.

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