Ovariectomy and Ovario-Hysterectomy

Removal of the ovary (ovariotomy, ovariectomy) or the ovaries and the uterus (ovario-hysterectomy) are indicated in several affections of the ovary and uterus such as:

* Uterine rupture
* Mummification with firm embedding in the uterine mucosa
* Pyometra with cervical adhesions
* Congenital abnormalities with collection of fluid inside the uterus
* Unilateral ovario-bursal adhesions or hydrobursitis
* Uterine or ovarian tumors

Ovariotomy and partial hysterectomy are also surgical procedures used in research for studies on the relationship between pregnancy maintenance and position of the corpus luteum, the mechanisms of maternal recognition of pregnancy and the utero-ovarian regulation and prostaglandin release.

Ovario-hysterectomy

Ovario-hysterectomy has been described only in llamas. The procedure is done under general anesthesia with the animal in dorsal recumbency, especially if the animal is young (small genital tract) or if the uterus is enlarged.^{(4, 18)}

The animal should be fasted 24 to 48 hours and receive systemic antibiotics 12 hours prior to surgery. The best surgical approach to ovario-hysterectomy in the llama is the ventral midline approach. The animal is prepared as for a cesarean section. A 30- to 40-cm skin incision is made from the cranial border of the udder towards the umbilicus. The uterus is completely exteriorized from the surgical opening and any fluid, if present in the uterus, is drained with a large bore needle attached to a flexible tube. The uterus should be flushed with saline solution and antibiotics, then sutured to avoid contamination of the abdominal cavity. All blood vessels, including the ovarian and cranial uterine arteries, are identified and ligated (double ligation). The broad ligament of the uterus can then be transected to allow manipulation of the uterus at the cervical level. The vagina should be closed with overlapping mattress sutures with No. 2 or 3 catgut. The reproductive tract is amputated proximal to the mattress sutures. The serosal surfaces of the stump are apposed by simple interrupted sutures. The abdomen is closed in the same manner as for cesarean section.

In some cases a modified flank approach is used. The incision is made 6 to 10 cm from the tuber coxae following a diagonal course in the direction of the fibers of the internal abdominal oblique muscle. The approach is similar to the one described for cesarean section in the dromedary.⁽¹⁸⁾

Ovario-hysterectomy can also be performed through a parainguinal approach.^{(1, 18)} The llama is positioned in lateral recumbency, the top back leg is positioned in abduction to expose the inguinal area (Figure 9.7). The incision is made about 8 cm cranial and dorsal to the inguinal canal over. The skin incision varies from 10 to 15 cm and is limited in its ventral aspect by the caudal superficial epigastric vessels. The subcutaneous fat and the facial sheaths of the external abdominal oblique muscle are dissected. The internal abdominal oblique muscle is dissected along its fibers to expose the peritoneum which is opened with scissors in the same direction as the cutaneous incision. The genital tract is exposed through the surgical opening by direct traction on the uterine horn. The ovarian artery and vein are double ligated, as is the uterine artery and vein that is adjacent to the caudal aspect of the uterine body. The ovarian ligament, mesovarium and broad ligament are cut to free the cranial part of the reproductive tract. Two large forceps are placed across the uterine body just cranial to the internal os of the cervix to insure hemostasis. The uterus is transected at the level of the body (between the two forceps). The edges of the sectioned uterine body are then closed with absorbable suture material. Closure of the surgical site in the parainguinal approach consists of a simple continuous suture pattern of the transverse muscle and peritoneum, followed by closure of the internal abdominal oblique muscle and the fascia sheath of the external abdominal oblique muscle. The skin is closed using a mattress pattern. Post-surgical care is similar to that following cesarean section.^{(1, 18)}
 

Ovariectomy

Ovariectomy in the female camelidae can be done via a parainguinal, ventral, or flank approach. The choice of a particular technique depends on the species, the age of the animal, the side of the ovary concerned (unilateral or bilateral), and the situation of the ovary (normal vs. abnormal). The flank approach can be used in multiparous animals because the genital tract is sufficiently developed to allow exteriorization via the flank. In young-animal ovariectomy or in the presence of large ovarian masses, the parainguinal approach is the preferred technique. The ventral midline approach is used only in llamas and alpacas and is ideal for bilateral ovariectomy. The best approach for the dromedary female is via the flank. However, with this technique each ovary has to be accessed from its respective side if the uterus is small.

Anesthesia and preparation of the animal for ovariectomy is similar to the technique described for cesarean section or ovario-hysterectomy. The ovary is exteriorized from the incision site by applying gentle traction. The ovarian vein and artery as well as surrounding vessels are ligated and the ovary is removed along with it ovarian bursa.

In the dromedary, we have used the flank approach for the removal of the affected ovary in cases of hydrobursitis.⁽¹⁷⁾ Food and water are withheld during the 48 hours prior to surgery. The animal is restrained in a sitting, sternal position and immobilized by an injection of xylazine (0.25 mg/kg IV). Anesthesia of the surgical site is provided by a paravertebral block and a line block of the surgical site. The surgical site is clipped and shaved over an area 30 cm x 30 cm, extending vertically from the processes of lumbar vertebrae down and horizontally from the last rib to the hip (Figure 9.8). The incision site is located in the middle of the paralumbar fossa. A vertical skin incision is made starting at about 10 cm ventral to the transverse process and extending ventrally for 15 to 20 cm, depending on the estimated size of the affected ovarian bursa (Figure 9.8).

After opening the 3 abdominal muscular layers and peritoneum, the hand of the operator is introduced into the abdominal cavity and directed caudally to the pelvic region where the uterus is identified by direct palpation. The uterine horn is grasped and examined throughout its length until the ovary and the affected ovarian bursa are identified. Because of the fragile nature of the ovarian bursa and the tremendous tension exerted by the accumulation of the fluid, traction on the oviduct should be avoided. Traction should be exerted first on the uterine horn until the bursa is visible at the level of the surgical site. In cases where there is an excessive amount of fluid, an aide should support the bursa by placing a hand within the abdominal cavity underneath the bursa. The ovarian bursa is exteriorized progressively by shifting the fluid away from the surgical opening and then gradually towards the exteriorized part until the whole bursa pops outside the abdominal cavity. The whole oviduct and the upper third of the corresponding uterine horn are readily visible at this point. Great care should be taken in manipulating the affected bursa because of the risk of rupture when the large amount of fluid is accumulated (Figure 9.9, 9.10) The ovary and affected bursa are resected in toto after the major vessels have been ligated at the third lower part of the uterine tube (Figure 9.10).

The abdominal cavity is closed in three layers. The peritoneum and the transverse abdominal muscle (M. transverses abdominis) are closed together with a simple continuous suture using chromic catgut No. 3. The internal and external abdominal muscles (M. Obliquus internus abdominis and M. Obliquus externus abdominis) and the subcutaneous facia are closed in a second layer with a simple continuous suture (catgut No. 3). The suture is anchored every 3 to 4 cm to the transverse muscle to remove any dead space and prevent formation of pockets. 3) The skin is closed using a continuous interlocking suture pattern (silk No. 6). Post-operative care consists of daily antibiotherapy and anti-inflammatory treatment for 10 days. Suture material is removed 3 weeks after surgery.

In cases where the condition is bilateral, both sides can be accessed through the same flank (Figure 9.10). However, when a large amount of fluid is present, or when the uterine horns are small (nulliparous or primiparous animals), it is necessary to perform the operation on each flank separately.

The animals should be palpated regularly for the next 3 weeks to avoid the development of adhesion and ovarian activity should be monitored. In the absence of complications, ovariectomized females can be bred 3 to 4 weeks after surgery.

References

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