Lacey Floyd
AN SC 457
Dr. Ed Jedrzejewski
Equine Reproductive Laparoscopy
Unlike most other procedures, laparoscopic surgery was first implemented in the human
medical field as opposed to equine medicine. It was quickly recognized that this technique could be
valuable in the realm of equine reproduction. Laparoscopy got its start in the equine world in the 1970s.
The first efforts to apply this relatively new technology were basic in nature and not of much note.
However, the use of laparoscopic techniques soon began to blossom. The first structures observed in
the mare using laparoscopy were that of the reproductive tract. Several manipulations of the tract were
also performed, the most notable procedures being ovarian biopsy and aspiration of ovarian cysts. Soon
after this foray in 1983, the horizons became a little broader for this blossoming technique. The male
reproductive system came into question next. Laparoscopy was used to find and locate a retained testis
in the abdomen in 1989. The field of equine laparoscopic surgery continued to grow with 27 papers
published in the 1990s and 62 manuscripts in the following ten years. As Dr. Dean Hendrickson stated,
“It [was] obvious that equine laparoscopic surgery is here to stay and provides many benefits over
traditional surgery for many surgical procedures.” In order to understand why any procedure has lasting
power, one must first understand what that procedure involves.
Obviously, as with any surgical procedure, a route must be created through the abdominal wall
to facilitate access to the area in which the procedure will occur. Small incisions are made in the
abdominal wall of the subject after sedation which will be comprised of a various combination of drugs
as per each veterinarian’s preference. Horses will also often be given an epidural. Depending on the
veterinarian performing the surgery, local anesthetic may be applied to the outer body wall and/or the
structures that will be altered or removed during surgery. The small incisions necessary for the surgery
are kept open through the use of cannulaes which come in both disposable and reusable forms which
accommodate both low- and high-cost operations respectively. Unlike traditional surgery, a working
space must be created because there is no gravitational displacement of organs, particularly when
performing standing laparoscopy. In order to make said space, the abdominal cavity must be inflated
with an inert gas. Carbon dioxide is a commonly chosen gas because it is not combustible, is typically
less expensive, and is not likely to create a gas embolism as it is soluble in blood. Atmospheric air may
also be used in low expense operations. Hand instruments are perhaps the most obvious article to be
addressed. These instruments are developed and modified from human laparoscopic instruments. The
primary difference is length otherwise they remain similar. They are inserted into the cannulaes for use
within the abdomen. Another rather important instrument needed to perform this procedure is the
laparoscope which houses the telescope, light source, and camera. Since the abdomen is not actually
open, a way to view the area in question is needed. Instruments are often introduced via different
cannulae in order to triangulate the location necessary for surgery. After alteration of the desired object
is completed, hemostasis, or the stopping of blood flow, must occur. This can be achieved by using
various tools. Such tools include: ligating loops, polyamide tie-raps, electrosurgical devices, vessel
sealing devices, ultrasonic cutters, coagulating devices, stapling devices, and surgical lasers. After
hemostasis is achieved, the instruments are removed, and the incisions closed, recovery can begin. This
process is considered minimally invasive and, as such, should allow for a simple recovery process.
Despite this, there are still advantages and disadvantages, as with any procedure.
The advantages of laparoscopy are numerous. First and foremost, this technique is minimally
invasive as the abdomen is accessed by small incisions as opposed to the much larger incisions
associated with traditional surgery. Laparoscopic surgery also leads to a reduced hospital stay. Smaller
incisions close and heal more quickly and, as such, decrease time spent in the hospital. As anyone
knows, hospital stays are expensive thus making a reduced hospitalization time more cost effective. In
addition to the reduced hospital stay and small entry incisions, laparoscopic surgery also allows for
quicker recovery time. In terms of surgical procedures, return to athletic production can be used as a
measure of success. A patient that recovers more quickly from surgery can return to its job sooner, and
in today’s world, horses are athletes that are required to perform thus making laparoscopic surgery
greatly advantageous to horses and horse owners alike. The typical recovery protocol for laparoscopic
surgery requires 24 hours of stall rest followed by hand walking the next day and a return to full exercise
in two weeks. In contrast, conventional surgery requires two weeks of stall rest followed by several
weeks of hand walking with a return to full exercise in 4 to 6 weeks. A reduction in post-operative pain
accompanies these other benefits and likely allows for them. These are advantages that laparoscopic
surgery provides the patient, but there are several advantages that extend beyond patient benefits.
There are also advantages to the surgeon performing the procedures. The most prominent
advantage for the surgeon is the improved visualization. The equipment used for laparoscopy allows a
surgeon to see structures when they are positioned more correctly in relation to other anatomical
structures. It also allows for magnification and better illumination of the structures in question.
Laparoscopy also has the potential to decrease the stress on the surgeon presented by traditional
surgery. This comes largely into play in regards to the manipulation of the other organs present in the
abdomen. Another complication associated with traditional surgeries that is not involved in laparoscopy
is general anesthesia. Without general anesthesia, the procedure becomes less labor intensive and
allows it to be simpler in concerns to sedation and anesthesia. Laparoscopic surgery can take advantage
of various types of hemostasis including tension-free hemostasis. This technique does not require the
surgeon to manual suture within the abdomen but rather allows the surgeon to cauterize sources of
bleeding. In turn, this makes surgery easier on a surgeon’s hands and reduces his or her stress. Despite
all of these advantages, there are still disadvantages associated with laparoscopic surgery.
Disadvantages come with any medical technique. Laparoscopy is no exception. As with the
advantages of this technique there are also disadvantages for both the patient and the surgeon.
Disadvantages to the patient mainly concern puncture of other organs surrounding the organ in
question. The organs that are often punctured or lacerated are the spleen, kidney, and gut. Procedures
involving finer structures such as the oviduct may cause further damage to those structures which is also
a concern. However, most of the disadvantages involved with laparoscopic surgery involve the surgeon
and the difficulty associated with manipulating the working environment inside the abdominal cavity, or
the pneumoperitoneum. These are, of course, also of concern to the patient’s health as the surgeon
directly affects the patient.
Laparoscopic surgery presents some difficulties that are not present when performing
traditional surgery. Perhaps the most difficult obstacle to overcome when performing laparoscopic
procedures is the lack of depth perception as a result of the two-dimensional view provided by the
camera within the abdomen. Evaluating a three-dimensional structure with a two-dimensional view is a
constraint that requires training to overcome. Another obstacle that laparoscopic surgeons encounter is
the lack of tactile sensation as they do not actually handle any tissue during the procedure. This limits
their ability to determine if a tissue is abnormal or where a tissue starts or ends. Just as the camera acts
as a surgeon’s eyes within the abdomen as do the instruments act as the arms of the surgeon. However,
the instruments are inserted into a very small diameter opening in the wall of the abdomen. This limits
the range of motion allowed for the long-handled instruments. The fulcrum effect is yet another factor
that plays into the difficulty of the surgery for the surgeon. This effect requires the surgeon to move the
instrument the opposite direction of which he wants the tips of the instrument to move. These factors
when combined require adjusting to when a surgeon is used to performing traditional surgeries. Fine
movements such as suturing, hemostasis, and surgical manipulation within the abdomen also become
more difficult in light of these obstacles presented by laparoscopic procedures. All of these increase the
difficulty of any procedure and, as such, the surgeon’s fatigue and stress. The stress and learning curve
involved may also increase time in surgery. There are also considerable initial costs to be factored into
the disadvantages of laparoscopy. When a surgeon is considering adding laparoscopic surgeries to his or
her repertoire, the demand for procedures requiring or using such techniques should be researched.
Reproduction is a large sector of the equine industry. As such, veterinary medicine often
revolves around producing equine athletes. Laparoscopic surgery, as a part of veterinary medicine, has
also conformed to the reproductive aspect of the horse world. The reproductive surgeries that can be
performed are numerous, and new procedures are currently being developed. The two procedures
commonly offered commercially that will be covered in this paper are ovariectomies and
cryptorchidectomies.
Ovariectomies can be performed standing or dorsally recumbent. Both flanks must be clipped
and prepared for surgery when performing a bilateral removal. This procedure requires 6 cannulas to be
put into place. The ovaries are also often desensitized with local anesthetic to prevent discomfort for
the mare. The ovaries are then removed. During ovariectomies any of the following methods can be
used to ligate and subsequently amputate ovaries: ligating loops, ultrasonic devices, vessel sealing
devices, electrosurgery, lasers, stapling devices, or polyamide tie-raps. Ligating loops and polyamide tieraps are relatively similar in that they both require putting suture material over the desired structure
and tightening it. Ultrasonic devices simply use sound waves to cut through tissue while coagulating it at
the same time. Vessel sealing devices use radio-frequency to dissect and coagulate during surgery.
Electrosurgery uses the traditional cauterizing of tissue within the body. Laser surgery amplifies the light
of certain substances to create heat and subsequently cut tissue. Stapling devices are the second
simplest method using staples to ligate the tissue. These methods all have their own drawbacks as well
as benefits, but all can be used to perform laparoscopic ovariectomies. After ligating the ovaries, they
are both are removed from the left flank after amputation. An enlargement of the initial incision is
required to remove the ovary. Ovaries are often dropped within the abdomen due to their dense
nature. If an ovary is dropped, it is highly recommended that the ovary be found and removed from the
abdominal cavity to prevent revascularization. In some instances, ovaries are removed that have tumors
associated with them. These tumors are known as granulosa thecal cell tumors, or GCTs. These cases
require only the preparation of one flank because tumors are typically only present on one ovary. They
also require slightly different methods regarding ligation and amputation. When performing an
ovariectomy in the dorsally recumbent position, the mare must be tipped into the Trendelberg position.
This method for performing ovariectomes requires general anesthesia unlike most laparoscopic
procedures. The Trendelberg position tips the mare’s head down while raising her pelvis up at a 30
degree angle. This allows abdominal viscera to move away from the area of interest. However, it is more
difficult to visual the ovaries in this position when compared to standing ovariectomies. Mares are not
the only horses to undergo gonadal removal, however. Stallions, perhaps, more commonly undergo
removal of their gonads therefore making cryptorchidectomies equally, if not more, economically
important.
As with ovariectomies, cryptorchidectomies can also be performed standing or dorsally
recumbent. In actuality, many aspects of the procedures are similar. The testes are also numbed with a
local anesthetic. One aspect that differs is that the testis can either be removed and emasculated much
like a typical gelding, or it can be amputated within the body cavity. This ligation and amputation can be
performed using any of the methods used for ligation and amputation of the ovary. If the stallion is a
bilateral cryptorchid both testes can be removed from the left flank. This does require a fourth cannula.
The ventral most incision must be enlarged to remove the testis. The testis can also easily be dropped
within the abdomen. It is more crucial to remove amputated testicles as they have the capability to
revascularize more so than ovaries. This would result in hormone production which, in most cases,
would be considered undesirable. Cryptorchidectomies can also be formed when the stallion is dorsally
recumbent. Much like ovariectomies, this requires the horse to be in the Trendelberg position, although
with less severe tilt. This approach is valuable when the animal is to be shown, as it does not require the
flanks to be clipped. Some horses, however, have already been shown and, as a result, are being used as
breeding animals. Unfortunately, some of the mares that have been chosen for this path have fertility
problems. Two recently developed laparoscopic procedures, oviduct flushing and administration of
prostaglandin gel to the oviduct, may help to improve fertility in these mares.
Prior to the development of laparoscopic oviductal flushing, there were few therapeutic options
for mares with oviductal disorders. With the addition of oviduct flushing and prostaglandin gel
administration, the options for therapy have become more diverse. Oviduct flushing involves
catheterization of the uterotubal junction and flushing the oviduct with 20 milliliters of sterile
methylene blue solution. The blue color of the dye allowed for the solution to be seen upon its exit of
the oviduct and entrance into the uterus. The solution itself was meant to mechanically flush any
obstruction out of the oviduct. This procedure was approached much like a laparoscopic ovariectomy
would be with entrance from the flank. The application of prostaglandin gel to the oviduct is also
approached in the same manner and is used to remove oviductal obstructions in the mare. The
prostaglandin gel applied to the oviduct causes contractions of smooth muscle which helped to expel
the oviductal obstruction much as endogenous prostaglandins would cause contraction of the oviduct to
push the embryo towards the uterus. These obstructions are likely to be an accumulation of debris as
opposed to fibrous tissue bound within the oviduct. These new uses of laparoscopy show a promising
future for this technique in the equine reproductive industry, but as with any procedure, there are costs
involved that must be evaluated to dictate the validity of the treatment for use at a practice.
According to a Dr. Cage Cruise with Southern Equine Associates, a cryptorchidectomy along with
other laparoscopic procedures can vary greatly in cost depending on the type of anesthesia used for the
surgery. However, a cryptorchidectomy generally costs between $1,500 and $2,000. The variables that
can increase the cost include the length of the surgery and the anesthesia needed. As a surgery
increases in length, the price also increases due to the cost of additional labor. Anesthesia can also
cause the price of any surgery to increase. Laparoscopic surgery can vary even more than traditional
surgery in this aspect because it can be performed under standing or general anesthesia. General
anesthesia costs significantly more. These variations can cause the price to increase the price to almost
$3,000. Despite the price variability associated with these procedures, they are economically viable for
many equine procedures to perform if they already have the facility to perform sterile surgeries.
Cryptorchidectomies or laparoscopic infertility treatments are of particular viability as they are both
surgeries that are of relative importance to horse owners. These procedures can be performed at any
veterinary practices with surgical facilities and, for that reason, are a good option for revenue for such
practices.
Works Cited
ALLEN, W. R., WILSHER, S., MORRIS, L., CROWHURST, J. S., HILLYER, M. H. and NEAL, H. N. (2006),
Laparoscopic application of PGE2 to re-establish oviducal patency and fertility in infertile mares:
a preliminary study. Equine Veterinary Journal, 38: 454–459.
doi: 10.2746/042516406778400628
Cable, Christina S. "Cryptorchid Surgery." TheHorse.com. Blood-Horse Publications, n.d. Web. 10 Nov.
2013. <http://www.thehorse.com/articles/10348/cryptorchid-surgery>.
D. A. Hendrickson, “Complications of Laparoscopic Surgery,” Veterinary Clincs of North America, vol. 24,
no. 3, pp. 557-571, 2008.
Dean A. Hendrickson, “A Review of Equine Laparoscopy,” ISRN Veterinary Science, vol. 2012, Article ID
492650, 17 pages, 2012. doi:10.5402/2012/492650
J.P. Caron, “Equine Laparoscopy: equipment and basic principles,” Compendium on Continuing
Education for Practicing Veterinarians, vol. 34, no. 3, pp. E1-E7, 2012.
KÖLLMANN, M., RÖTTING, A., HEBERLING, A. and SIEME, H. (2011), Laparoscopic techniques for
investigating the equine oviduct. Equine Veterinary Journal, 43: 106–111. doi: 10.1111/j.20423306.2010.00143.x