Insight

Fall 2004

Minimally Invasive Surgical Techniques Lead to Better Outcomes

In the 1960’s sci-fi flick, Fantastic Voyage, a group of scientists and their transport vehicle are shrunk to microscopic size and dispatched to repair a deadly blood clot in the brain of a brilliant scientist. This cinematic vision of minimally invasive surgery has not yet come to pass, but shrinking medical instruments and forays inside the body with specialized equipment are enabling surgical procedures that not so long ago seemed the stuff of movie fantasy.

Dr. Dean Hendrickson, an Associate Professor with the Department of Clinical Sciences, is a pioneer in such minimally invasive surgery, generally known as endoscopic surgery, specializing in equine laparoscopy, in which a viewing tube called a laparoscope is used to see inside the abdomen and pelvis. High-precision surgical instruments are used along with the laparoscope to perform specific procedures in the pelvic and abdominal areas, including corrections for cryptorchid horses (in which one or both testicles have not descended), ovariectomy (removal of the ovaries), and treatment of nephrosplenic ablation (one cause of colic in horses).

“The benefits of laparoscopy are smaller incisions, lower morbidity, and a faster return to function for our equine patients,” Dr. Hendrickson said. “The downside is that laparoscopy requires specialized equipment and training and is a technically demanding field.”

When Dr. Hendrickson arrived at CSU from the University of Wisconsin nine years ago, there was not a laparoscopy program in place. He had been trained on laparoscopic equipment and techniques while at the University of Wisconsin . As a large animal surgeon, he worked with small animal surgeons and human surgeons to develop new methods of treating conditions in horses that previously required large incision surgery and carried higher risk. After coming to CSU, Dr. Hendrickson dove in head first, ordering equipment and establishing a laparoscopy program for the Veterinary Teaching Hospital’s equine patients.

“Laparoscopy has been around in veterinary medicine since the early 1970s, when it primarily was used in research,” said Dr. Hendrickson. “In the early 1980s, it was starting to be used as a diagnostic tool, and in 1993, we started to see surgical applications. It quickly became apparent that laparoscopy could dramatically improve the surgical outcomes for horses.”

In standing laparoscopy, three or more small incisions are made in the horse’s flank. One incision is for the laparoscope, with miniaturized camera and light, to provide images of the abdominal cavity, and the other incisions are for the surgical tools needed for the procedure. Two people typically work the equipment during a laparoscopy, one to move the camera and the other to do the actual procedure. Images from the camera are displayed on a monitor that the surgeon follows to complete delicate operations. Synchronicity between the two individuals is essential, as one provides the “eyes” and the other provides the “hands.”

Cryptorchid castration was one of the first surgical procedures developed for equine laparoscopy. The standard surgery often was difficult at best, requiring general anesthesia, large incisions, and lengthy recovery times. In some cases, surgeons could not find the testicle in the abdominal cavity, and surgery had to be repeated. When Dr. Hendrickson developed the laparoscopy technique, standing horses could be operated on using local anesthetic and light sedation. Large incisions were replaced with three small ones, and rather than going in blind, the laparoscope enabled surgeons to locate and display on the viewing screen the testicle location in the abdominal cavity.

Dr. Hendrickson also has developed laparoscopic techniques for ovariectomy, decreasing pain and suffering, and the potential for complications in horses that must undergo this procedure. In addition, he has worked with new techniques to correct nephrosplenic entrapment of the large colon by performing nephrosplenic space ablation. In this condition, the large colon gets caught in a small trough between the spleen and the kidney and can cause the horse to colic. Traditional surgical corrections included a huge incision and removal of a rib. With laparoscopy, the colon is removed from the trough, and then the spleen is sutured to the peritoneum around the kidney to prevent a recurrence. Results so far show the procedure is 100 percent successful in preventing a recurrence of nephrosplenic entrapment.

“It’s just so amazing to be a part of this exciting work,” said Dr. Hendrickson. “We have owners come in who can’t believe their horses have just had surgery – the horses look so good and have so much energy. The availability of these techniques, and development of new laparoscopy protocols, means that we can continue to offer improved health care to our patients and help veterinarians bring these new technologies into their own practices.”

When not treating his patients, Dr. Hendrickson works to advance the field of equine laparoscopy. He has ongoing research looking at ways to provide improved pain relief for cryptorchid horses during the laparoscopy procedure, as well as improved sedation techniques that will make it easier for veterinarians in private practice to administer; he has developed a knot-suture combination for laparoscopy; he uses laparoscopy extensively as a teaching tool so students can visualize anatomy when they are doing equine transrectal palpations; and he conducts regular continuing education courses in laparoscopy for practicing veterinarians.