surgery | Horse Racing Free Tips

AAEP Convention: Standing Arthroscopy Can Be Used On More Than Stifles

When traditional diagnostic tools such as X-ray and ultrasound provide no definitive diagnosis for an equine lameness, a vet may perform an arthroscopy. While this procedure typically requires putting the horse under general anesthesia, a needle arthroscopy can be done while the horse is under standing sedation, Dr. Alvaro Bonilla said at the virtual 2020 American Association of Equine Practitioners Convention and Trade Show.

A safe, reliable procedure, needle arthroscopy is less risky and less costly to the owner; putting a horse under general anesthesia for surgery has its own risks, including recovery. While typically used for diagnostics, a standing arthroscopy can also be used therapeutically for septic joints and small osteochondral fragments, specifically for dorsal fragments of the first phalanx in the fetlock, Alvaro says. However, the procedure does still have limitations.

Previously, needle arthroscopy was used only in the stifle joint; Alvaro reports that now it can be used successfully to evaluate multiple synovial structures, including shoulders, fetlocks, hocks, radiocarpal and middle carpal joints, and carpal sheaths.

When using this diagnostic tool, it's important that the horse is sedated, but not overly so, which could make him unsteady and make the procedure not only difficult, but dangerous. Additionally, the surgical site must be sterile, which can be difficult as debris can fall onto the joint or the horse can urinate. Potential for both complications can be decreased by using blankets and inserting a urinary catheter.

An adjustable, lightweight splint made from stainless steel and aluminum is used during the procedure; to ensure as successful an outcome as possible, horses should be acclimated to wearing the brace before being sedated for the surgery.

The surgical area should be bandaged for four to five days following the procedure; horses that had the procedure for diagnostic reasons can go back to work as soon as the bandages are removed.

Laparoscopic Surgery May Prevent Recurrence of Nephrosplenic Entrapment

Nephrosplenic entrapment is a type of colic that occurs when a horse's colon shifts and settles over the nephrosplenic ligament, trapping the colon and its contents, which causes distention and pain. Nearly 9 percent of colic cases seen in equine clinics are caused by nephrosplenic entrapment.

Though it's unclear what makes some horses more prone to the condition, it's suspected that a large abdomen, abnormalities in how a horse's colon moves and the shape of the nephrosplenic space may play a role.

There are several treatments for nephrosplenic entrapment, including administering medication to shrink the spleen and then working the horse to try to get the colon back to a normal position. Anesthetizing a horse and rolling him back and forth to try to free the colon can also be done. Finally, surgery may be performed to manually free to the colon.

Though most horses with nephrosplenic entrapment recover, nearly 21 percent of survivors will experience another entrapment. The University of Pennsylvania's New Bolton Center found that a surgical procedure to close the nephrosplenic space can prevent the entrapment from occurring again.

Veterinarians can tack surgical mesh over the top of the spleen, which keeps the colon from slipping into the space. This can be done laparoscopically in about 30 minutes and has no risk of failure. Veterinarians looked at the records of 26 horses that had experienced nephrosplenic entrapment that had the space closed with mesh: not one horse had a recurrence during the follow-up period, which was up to seven years.

Common Colic Myths Debunked

The signs of colic are well-known to many horse owners: abdominal discomfort shown by pawing, kicking at the belly, repeatedly rolling, sweating and increased heart and respiration rate. Though colic is unfortunately common in horses, only about 10 percent of colic cases require surgical intervention to resolve.

Colic surgery can seem scary, but improvements in the past few decades have lessened the chance of a negative outcome, reports The Horse. Yet, myths regarding colic surgery remain. Dr. Jacqueline Hill, who practices at Littleton Equine Medical Center in Colorado, dispels some of the most common colic surgery myths.

Myth 1: A horse will never return to pre-surgery performance levels. Though colic surgery is a major surgery with a long recover period, horses can go back to their pre-surgery performance levels. A study that used over 200 horses of different breeds found that 84 percent of the horses returned to their discipline after colic surgery and that 79 percent were performing at or above the level they were at before the surgery.

Myth 2: A horse can be “too old” for colic surgery. The life expectancy for horses, like humans, has lengthened in the last few decades, with many horses ridden well into their 20s. A recent study from the University of Pennsylvania compared horses between 4 and 15 years old that had colic surgery with horses that were over 20 that had colic surgery. They found that both categories had similar post-operative complications and survival rates.

Myth 3: A horse is never the same after having a resection. Horses tend to fare differently depending on the section of intestine that has been resected: horses that have had their small intestine resected tend to fare better than those that have had the end of the intestine resected. It was recently reported that horses that have had their large colon resected have 65 to 75 percent long-term survival rates; small-intestine only resections see up to 75 percent of patients with long-term success.

More evidence is needed to resolve the myth that horses that have had colic surgery are more prone to colicking again. Studies have reported that between 0 to 35 percent of post-surgical horses have another colic episode within 12 months of a colic surgery. Factors that appear to affect this include what portion of the bowel was affected and what surgical procedure was used. Generally, if a horse doesn't colic in the first year after surgery, his risk of colicking again is similar to a horse that didn't have surgery.

Abdominal Surgery Poses Greatest Risk Of Surgical Site Infection

As with human surgery, there is always a potential for infection during equine surgery, Drs. Kelmer, Paz, Tatz, Dahan, Bdolah-abram and Oreff reviewed 198 post-operative complications related to surgery procedures on 167 horses at the Koret School of Veterinary Medicine in Israel over a 15-month period.

The study reviewed 40 percent abdominal surgeries, 30 percent orthopedic surgery and the rest were general surgeries that had a 9 to 20 percent chance of developing a surgical site infection. The incidence of infection was 16.7 percent during the study period.

The study team noted that post-operative surgical site infections created difficulties with recovery, increased the length of stay in the hospital, increased client coats sand delayed return to work. It addition, surgical site infections caused an increase in equine morbidity and mortality.

Of all the surgeries performed, abdominal procedures had the highest risk of infection with 28 percent. This may be because of the length of the incision or the weight of the intestines on the incisions.

The scientists identified the following as factors that increase the risk for a surgical site infection:

Type of surgery.
Having a repeat surgery in less than 6 months in the same area or in an area near the original incision. Abdominal procedures are particularly at risk.
Weight of the horse. Heavier horses have more weight resting on the incision line in their abdomen.
Gender. In the study, only 2.3 percent of stallions developed infections, compared to 16.1 percent of geldings and 24.3 percent of mares; 50 percent of pregnant mares had surgical site complications.
Recovery from anesthesia. A horse that has a hard time recovering from anesthesia may increase his risk of infection development by four times.

Abdominal procedure infection rate ranges from 7 to 37 percent; arthroscopic surgery infection rate was less than 1 percent. Overall infection frequency in orthopedic procedures was around 10 percent.

The team found that other factors may amplify infection risk. These include time of day and season when the surgery takes place; the surgeon; and a horse's breed and age. They also note that as this study looked at cases between 2011 and 2013, surgical techniques, bacterial resistance and bacterial populations have changes, so additional studies are needed.