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EQUINE LAPAROSCOPY
What is laparoscopy?
Laparoscopy is a technique to perform surgery within the abdomen without making a traditional incision through which the surgeon could put their hands. It utilizes a long, narrow, rigid lens with a light source (a laparoscope) to view inside the abdomen. The laparoscope is attached to a video camera for viewing on a television monitor. Long-handled surgical instruments are specifically designed for use during laparoscopy and the instruments are passed through separate cannulae (tubular ports) into the abdomen. Many cannulae can be used simultaneously with multiple surgeons operating the different instruments (Figure 1).
Figure 1. A laparoscopic instrument (A) is being placed through a cannula (B) that is already in the abdomen of a horse under anesthesia. The laparoscope (C) is placed through a separate cannula to look inside the abdomen.
During most laparoscopic procedures, the abdomen is kept distended, or filled, with carbon dioxide. The process of distending the abdomen is referred to as insufflation. Distension is important because it allows the surgeon room to work and increases visual access to many of the abdominal organs. Depending on the surgery and the surgeon’s preference, the abdomen may be distended before or after placement of a cannula and the laparoscope.
Some procedures are optimally performed using a combination of laparoscopy and traditional surgeries. This is generally referred to as hand-assisted laparoscopy. The laparoscope allows the surgeon to see what he/she is doing within the abdomen. A larger incision is required for introduction of the surgeon’s hand into the abdomen.
What are the benefits of laparoscopy?
Laparoscopy is a minimally invasive surgical technique. This means that the surgery is performed through several small incisions. Thus,
- Hospitalization and rehabilitation time are reduced,
- Discomfort associated with incisional healing is reduced and thus, the pain medication required is also reduced, and
- The cosmetic outcome is generally excellent.
The laparoscope provides direct magnified visualization of the surgery site. Thus,
- Surgeries can be performed in areas that cannot be seen with traditional surgical approaches, and
- Surgical sites can be critically evaluated for control of bleeding (hemostasis) and placement of sutures or other implants.
Many laparoscopic procedures are performed on the standing horse with the use of sedation and local anesthesia. Thus, the inherent potential complications of anesthesia and recovery from anesthesia are avoided.
What are the limitations of laparoscopy?
Specialized equipment and surgical skills are required for laparoscopy. Therefore, laparoscopic procedures are generally only performed at large hospitals by ACVS board- certified veterinary surgeons.
Not all regions of the abdomen are accessible with laparoscopy. Some regions are better accessed when the horse is standing, while others are better seen while the horse is on its back under general anesthesia.
Not all types of surgeries can be performed safely within the abdomen through small incisions. Because of the large size of some of the abdominal contents and the relatively small size of laparoscopic equipment, often it is more practical to perform surgery through a standard open incision. For example, it is quicker and more efficient to remove a portion of dead intestine through a standard incision.
What are the most common complications of laparoscopy?
Most of the complications associated with laparoscopy occur during placement of the cannula and insufflation of the abdomen with carbon dioxide. The complications include:
- Laceration of vessels within the body wall,
- Laceration or puncture of abdominal organs, and
- Insufflation outside of the abdomen within tissue planes of the body wall (retroperitoneal insufflation).
Specialized trocars (i.e. self-retracting and transparent) have been designed to minimize the risk of laceration or puncture of abdominal organs. Additionally, some surgeons prefer to insufflate the abdomen prior to cannula placement to minimize these potential problems. For an experienced surgeon, the complications associated with laparoscopy are minimal and usually do not impact the completion of surgery or cause long-term problems.
What kinds of surgeries are performed using laparoscopy in horses?
Exploratory and Diagnostic Procedures:
Laparoscopy provides good visual access to many intra-abdominal organs. Portions of the gastrointestinal tract (small intestine, small colon, large colon, etc), urinary system (bladder), genital tract (ovaries, uterus, intra-abdominal testicles), spleen, and liver are readily seen during exploratory laparoscopy. The ability to access different organs is dependant on the placement of the laparoscope (right or left flank versus ventrum [underside of belly with the horse on its back]). The approach chosen is generally based on the area of interest.
Exploratory laparoscopy may be a diagnostic test offered to clients whose horse demonstrates chronic, intermittent colic (abdominal pain) of unknown origin. It can also be used to further evaluate and potentially biopsy abnormalities in the abdomen detected by other diagnostic tests (i.e. ultrasound, rectal palpation, or bloodwork).
Gastrointestinal Tract:
Adhesiolysis. The term adhesion is used to describe an abnormal fibrous band of tissue within the abdomen which is often sticking or “adhering” to intestine. Adhesions may be associated with colic if they prevent the normal movement of feed material within the gastrointestinal tract. Adhesions are formed secondary to inflammation in the abdomen. This is most commonly associated with previous abdominal surgery, but may be related to other conditions such as peritonitis (infection and inflammation of the tissue lining the abdomen) or umbilical infection. Laparoscopy can be used to identify and break down these adhesions (adhesiolysis). The use of laparoscopic surgery, rather than a traditional surgical approach, decreases handling and exposure of the gastrointestinal tract during surgery and, thus diminishes the potential for further adhesions (Figure 2).
Figure 2. Inside the abdominal cavity, a laparoscopic scissors is being used to transect adhesions between the intestine and body wall.
Mesenteric rent repair. Mesentery describes the tissue that carries blood and lymph vessels to the intestinal tract. Tears (rents) in the mesentery can be congenital (present since birth) or acquired (develop later in life during times such as foaling). Mesenteric rents may lead to colic if a portion of the intestine becomes entrapped, or stuck, through the hole. If necessary, correction of the entrapment and resection of the entrapped portion is performed using traditional surgical methods. However, if the rent cannot be closed because its location is inaccessible via a traditional surgical approach, laparoscopy may provide an alternative method for closure.
Rectal tear. Rectal tears can occur in horses secondary to palpation per rectum (for reproduction evaluation or colic) or during foaling. A rectal tear is a life threatening condition that is difficult to treat due to the potential for severe contamination and subsequent infection of the abdomen. A method for laparoscopic repair of rectal tears has been developed and tested experimentally, but has not gained widespread use clinically because of the difficulty in accessing some tears.
Nephrosplenic space closure. One cause of colic in horses is displacement and entrapment of the large colon over a ligament that connects the spleen to the kidney (nephrosplenic ligament). This is referred to as nephrosplenic or renosplenic entrapment, or left dorsal displacement of the large colon. In approximately 5-10% of horses the condition is recurrent (i.e. it happens more than once). In order to prevent recurrence several methods for laparoscopic closure, or ablation, of the space between the spleen and the kidney have been developed. The space may be closed using sutures or by placement of a plastic mesh (Figure 3a,b).
Figure 3a. Laparoscopic view of the normal nephrosplenic space prior to surgery.
Figure 3b. The same view as in Figure 3a, but the space has been filled with a mesh and fibrous tissue to eliminate the possibility of colonic entrapment.
Colopexy. In addition to becoming displaced and entrapped between the kidney and the spleen, the large colon can develop a right dorsal displacement or twist on itself (large colon torsion or volvulus). To prevent recurrent displacement or volvulus of the colon, a portion of the colon can be sutured down to the body wall (colopexy). This can be done through a traditional surgical approach at the time of colic surgery or laparoscopically following recovery from colic surgery. Colopexy is generally reserved for non-performance horses and broodmares that have a history of multiple episodes of displacement or volvulus. It is important to discuss these options with your ACVS board-certified veterinary surgeon. Find an ACVS Veterinary Surgeon.
Urinary System:
Bladder stones—cystic calculi. The formation of stones (calculi) within the urinary tract is dependent on a number of factors that are not fully understood. In horses, most stones that require surgery are in the bladder of geldings. Horses with bladder stones show clinical signs such as posturing to urinate without urinating, frequent urination of small amounts, and blood in the urine especially after exercise. The bladder of the horse can be a difficult area to access through traditional surgical approaches. A technique for laparoscopic removal of bladder stones from a ventral approach under general anesthesia has been developed. While the initial surgical incisions are small, one incision will have to be enlarged to allow removal of the stone from the abdomen.
Ruptured bladder. A ruptured bladder is most commonly seen in neonatal (newborn) foals. Colts appear to be predisposed. Affected foals do not urinate, as expected, within hours of birth and show clinical signs of straining to urinate. Eventually, they become depressed and systemically ill due to electrolyte imbalances. A technique for laparoscopic repair of a ruptured bladder has been developed.
Nephrectomy. Nephrectomy, or surgical removal of a kidney, is not commonly performed in horses. Indications for nephrectomy might include urinary stones within the kidney or very severe infection of one kidney. Traditional surgical approaches to the kidney provide limited visual access and may require rib resection. Recently, a technique for hand-assisted laparoscopic nephrectomy has been published.
Genital Tract:
Ovariectomy. Ovariectomy is the surgical removal of an ovary. Indications for ovariectomy include a tumor of the ovary and behavioral modification. Laparoscopic and hand-assisted laparoscopic ovariectomies are most commonly performed with the horse standing, and under sedation. Different techniques to prevent bleeding have been evaluated. One of the skin incisions is often enlarged to remove the ovary from the abdomen.
Cryptorchid castration. A cryptorchid testicle is a term used to refer to an incompletely descended testicle. Normally, during development, the testicle travels out of the abdomen, through the inguinal canal, and into the scrotum. If the testicle remains in the abdomen or inguinal canal, castration is more difficult. The testicle must be removed or the horse will continue to show stallion-like behavior. Laparoscopic cryptorchid castration can be performed with the horse standing or under general anesthesia.
Movie1- A left flank laparoscopic view in the standing horse. The intra-abdominal testicle is grasped and a loop of suture is place around the vascular pedicle to ensure ligation of the vessels prior to transection and removal of the testicle.
Hernia Repair:
Inguinal hernia. An inguinal hernia refers to intestine slipping through the inguinal ring (the route that the testicle descends into the scrotum and the vessels that supply the testicle pass through). If the intestine is not severely compromised it may be possible to remove the intestine from the ring and then use specialized equipment that places sutures, staples, or a plastic mesh to close the ring. If the intestine is compromised and tight within the ring a traditional surgical approach will be required to remove the intestine and address any problems. The ring can be closed laparoscopically at a later date. The laparoscopic procedure can be performed in a standing horse. It is important to discuss the advantages and potential disadvantages of this with your ACVS board-certified veterinary surgeon
Abdominal wall hernia repair. Infrequently, an abdominal wall hernia (weak spot in the abdominal body wall) can develop after surgery. If not addressed, a large hernia can result in long-term loss of use for athletic horses or brood mares. Standard mesh placement to strengthen the body wall is expensive and has some inherent risk of complications. Laparoscopy can be performed to assess the hernia from inside the abdomen, and secure the mesh from inside the abdomen so the standard open surgery is not necessary.
Umbilical remnant resection. The umbilicus (belly button) is the portion of the umbilical cord that remains attached to the foal following birth. It can become infected and require removal in some foals. A laparoscopic technique can be used for resection of the umbilical remnants.
Thoracoscopy
Thoracoscopic surgery is a type of surgery that uses the same equipment and techniques that were described above for abdominal problems, but for the thorax (chest cavity) instead of the abdomen. The advantages (smaller incisions, less postoperative discomfort or complications) and the disadvantages (limited ability to deal with larger abnormalities) are similar. It is most often used for diagnostic purposes to see abnormal areas of lung or obtain biopsies to help better define the abnormality. It can also be used to access and debride an abscess associated with pleuropneumonia.
Conclusion
Laparoscopy is a specialized field of surgery that has many advantages over standard surgical techniques. Laparoscopy cannot replace many common surgical procedures and it requires specialized equipment and training. Any questions you have about laparoscopy should be directed to your ACVS board-certified veterinary surgeon.
—Kira Epstein, DVM, Diplomate ACVS
—Eric Parente, DVM, Diplomate ACVS
Posted 9/8/2006
Updated 9/22/2009 by Drs. Epstein and Parente
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