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What is a Diplomate?
The term "ACVS Diplomate" refers to a veterinarian who has been board certified in veterinary surgery.

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Standing Equine Laparoscopic Ovariectomy

The term "ACVS Diplomate" refers to a veterinarian who has been board certified in veterinary surgery. Only veterinarians who have successfully completed the certification requirements of the ACVS are Diplomates of the American College of Veterinary Surgeons and have earned the right to be called specialists in veterinary surgery.

Your ACVS board-certified veterinary surgeon completed a three-year residency program, met specific training and caseload requirements, performed research and had research published. This process was supervised by ACVS Diplomates, ensuring consistency in training and adherence to high standards. After completing the residency program, the individual passed a rigorous examination. Only then did your veterinary surgeon earn the title of ACVS Diplomate.

Overview: 

Indications for ovariectomy in the mare include removal of benign tumors or to achieve behavioral modification related to estrus.  Many surgical approaches and techniques have been described.  They include removal under general anesthesia in dorsal recumbency (positioned on the back), standing through the flank, or removal through the vagina with a crushing-type instrument. With the advent of laparoscopic (keyhole) surgery, all other techniques have become relatively dated simply because the laparoscopic approach is minimally invasive, avoids the risk of general anesthesia, greatly improves visualization and access to the base of the ovary and its blood supply (pedicle), and provides a cosmetically superior result with decreased convalescence.

Signs and Symptoms: 

The most common reasons for ovariectomy is removal of benign tumors affecting the ovary called a granulosa thecal cell tumor (GTCT).  These tumors are discovered because behavioral aggressive, even stallion like tendencies, are identified toward other horses and people. 

Additionally, ovary removal can attenuate persistent signs of estrus (being in season), when other forms of medical and hormonal therapies have been attempted.  There is some controversy and difference in opinion regarding the success of this procedure to provide modification in behavior.

 

Diagnostics: 

Diagnosis is based on recognition of aggressive clinical signs, ovarian palpation and ultrasound and confirmation with blood work evaluating circulating elevated levels of estrogen, testosterone and inhibin.

Treatment: 

As stated, standing laparoscopic ovariectomy allows for direct visualization and access to the target organ. Once comfortable with the procedure, it is relatively easy to perform and provides a cosmetic result with a reduced period of convalescence.

Pre-Operative Preparation: 
Since the ovaries are located in the abdomen immediately adjacent to the gastrointestinal tract it is important to withhold feed for 24–48 hours to allow for visualization of the ovaries, which lie suspended toward the back of the horse near the pelvis.

Laparoscopic Ovariectomy
Procedure: The mare is sedated and restrained in stocks. The hair in the flank on the affected side is clipped, sterilely prepared, draped and blocked with local anesthetic. Three small (1.5 cm) incisions are made within the flank region and specialized trocars or rigid tubes are placed into the abdomen allowing introduction of the laparoscope (rigid long camera) through the trocar into the abdomen, so that internal structures can be visualized (Figure 1). Instruments and devices to grasp and cut the ovary while sealing the blood vessels are placed through the remaining 2 portals. (Figures 2, 3a, and 3b). The abdomen is insufflated or expanded with carbon dioxide (CO2) gas to allow for better visualization of the ovary and its attachments to the uterus. The base of the ovary is locally anesthetized preceding dissection. Once the dissection is complete (Figure 4), the ovary is firmly grasped with a long instrument and one of the small incisions is extended to allow for removal through the body wall. The pedicle or base is then observed to ensure that there is no bleeding. Occasionally, the ovary is too large to remove and may need to be transected and removed in stages. Fluid is sometimes aspirated to allow for size reduction. Incisions are typically closed routinely. (Figure 5)

 
 
Aftercare and Outcome: 

Postoperatively, the mare is maintained on antibiotics and anti-inflammatories for 2–5 days. The CO2 gas that is used to insufflated or expand the abdomen can sometimes cause a low-grade inflammatory response within the abdomen which may lead to low grade transient fever. This is usually short-lived and resolves within 48 hours. Food is gradually reintroduced over the next few days. Incisions heel within two weeks and horses return to work typically within one month.

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Also known as: 
Standing Equine Laparoscopic Ovariectomy

This Animal Health Topic was written by and reviewed by Diplomates of the American College of Veterinary Surgeons.  Any opinions stated in this article are not necessarily the official position of the American College of Veterinary Surgeons.

The American College of Veterinary Surgeons recommends contacting an ACVS board-certified veterinary surgeon or your general veterinarian for more information about this topic.

To find an ACVS Diplomate, visit www.acvs.org/find-a-surgeon.