Post-Surgery Prognosis in Horses
"He needs surgery."
This assessment is one no horse owner wants to hear from his or her veterinarian. Surgical intervention can be costly and risky, and a horse's response to anesthesia and surgical procedures can be unpredictable. Plus, after your horse has gone under the knife, what's his prognosis for a full recovery? What obstacles might you face and what should you expect during the recovery process?
To answer these questions, we consulted three veterinarians who handle a considerable number of emergency referrals: Bradford Bentz, VMD, of Bluegrass Equine Performance and Internal Medicine in Georgetown, Ky.; Langdon Fielding, DVM, Dipl. ACVECC, who runs the intensive care unit at Loomis Basin Equine Medical Center in Loomis, Calif.; and Liberty Getman, DVM, Dipl. ACVS, a surgeon at Ocala Equine Hospital in Ocala, Fla. With their help, we'll trace the typical course of treatment and prognosis for four equine emergencies that often require surgical intervention as well as other common procedures.
Bentz compares sizing up a colic case to "trying to ascertain what's going on in a black box. That black box is the abdomen, and we don't have a good way of being able to see inside it."
Given the challenges general anesthesia poses for horses' respiratory and circulatory systems, Bentz says, "If you don't need to open the abdomen, you shouldn't. But if there's persistent pain and an inability to resolve the problem, you do go in (by performing an exploratory celiotomy--a surgical incision into the abdominal cavity), because you need to diagnose definitively the cause of a colic that is not responsive to nonsurgical interventions."
A surgeon can then perform a hands-on evaluation in the abdomen to assess, diagnose, and attempt to correct any problem. "With today's advanced anesthesia, respiratory, and circulatory support, the risks imposed by surgery are relatively small versus the risk of a delayed correction for a colic with a surgical cause," says Bentz.
Fielding ranks the horse's most critical needs following colic surgery: "If the horse can drink on its own, (it's important) that it does drink; if it can't, (it's important) we're providing fluid in the correct amount. No. 2 is probably nutrition: maintaining the horse's nutritional status with food it takes in itself or food we give intravenously." Veterinarians also monitor manure production (i.e., for signs of diarrhea), which can indicate a developing problem. The ICU team administers and monitors the effects of antibiotics and pain-reducing anti-inflammatories as well. And, adds Fielding, "we're on the lookout for infection both around the incision and in nonsurgical areas such as around catheters, and even checking that there isn't an overgrowth of bacteria in the gut resulting from stress or antibiotics, which can lead to diarrhea."
Bentz says a common problem following colic surgery is postoperative ileus, or a lack of gut motility, likely due to an imbalance in the autonomic (involuntary) nervous system that disrupts movement of ingesta. Veterinarians can administer medication to help restore normal function; but until motility returns, ileus can cause such problems as a gas/fluid buildup that increases gastrointestinal (GI) tract discomfort, requiring removal of the gastric reflux by a nasogastric tube. He also notes that reobstruction requiring repeat surgical intervention is uncommon, but can occur.
After colic surgery a horse goes home for three to six months of recuperation. "The surgeon writes a set of instructions on discharge," says Bentz. Those instructions typically include straight stall rest for the first month, then some hand-walking, and eventually limited paddock time. Careful monitoring for infection, discomfort, and any recurring GI problems is of utmost importance during the recuperation period. With such compliance, he says, "in general, horses do well following colic surgery."
Laceration treatment begins with determining the injury's size and location. The major worry is whether it involves any major structures: Does the laceration go into a joint or a tendon sheath, creating an entry point for infection? Or, has it cut any tendons or ligaments? If a laceration requires surgical repair, its location and severity, along with the horse's temperament, determine whether the veterinarian anesthetizes the horse for surgery or performs the procedure with the horse awake and standing, but sedated. Before anesthetizing the horse, however, Getman recommends taking radiographs (X rays) of the injured area. "Horses can have problems recovering from anesthesia on normal limbs," he says. "I don't want to ask a horse to recover from anesthesia standing on a leg with an underlying bone problem."
With most uncomplicated lacerations--and even those involving a joint, if treated promptly--prognosis for full athletic recovery is very good. Cases referred to a hospital usually remain there three to seven days, with veterinarians and technicians changing bandages and administering local wound care.
Getman says more extensive or contaminated lacerations require up to a week of daily regional limb perfusions. "We put a tourniquet on the leg and inject antibiotics into a vein below it, providing really high levels of antibiotics right where the laceration is," she says. The horse might also receive intravenous (IV) antibiotics for a few days, plus an anti-inflammatory.
When the horse is released to go home, Getman says, expect that he will need two or more weeks of stall rest, with daily to every-other-day bandage changes, daily temperature checks, and oral medication administration. By that point, "there may be a little discharge on the bandage, but there shouldn't be a lot," Getman explains. "It shouldn't have a foul odor. The leg shouldn't be hot and painful. And the horse shouldn't have a fever or be lame. I tell the owner to call me if any of those things occur." After the horse has completed the recommended stall rest, the regular veterinarian can remove the sutures and decide whether the animal is ready to resume normal activity.
One complication Getman advises watching for is "some of the sutured part of the laceration coming apart a little. This isn't generally a long-term problem, but it requires more local wound care and monitoring and probably stall rest and antibiotics until it heals on its own."
Infected joints can occur in:
- Foals with low immunity levels (i.e., from premature birth or insufficient colostrum intake) or an early illness that affects the joints;
- Horses that have experienced a laceration or puncture wound to a joint; and
- Horses that have undergone joint injection or joint surgery.
In all three situations the animal "is very, very lame and may also have a fever," Getman says. "The joint may be painful, hot, and swollen." Regardless the cause, the sooner treatment (e.g., active cleanout of the infected area) begins, the better.
In cases caught early, a veterinarian can flush out the joint easily, using needles and pressurized sterile fluid. But the longer infection has been present, the harder it is to dislodge the buildup of pus, which contains many white blood cells produced by the inflammatory process. Arthroscopic surgery, using a camera and large volumes of fluid, is more efficient but also more expensive. "Either way," says Getman, "the joint needs to be flushed aggressively with a lot of sterile fluid to get out all that infected material."
Once the joint has been flushed, the horse usually goes on IV antibiotics. The veterinarian might also deliver antibiotics directly into the joint using regional limb perfusion. Joints flushed within 12 to 24 hours after sustaining a laceration or puncture wound have an excellent prognosis; after five to seven days, any infection is usually gone. Infections following joint injection or surgery are harder to detect because heat and swelling might take a week or more to appear. A horse usually requires at least a week (or even a month) of hospitalization to overcome these injection- or surgery-derived infections. Many foals respond quickly and can be discharged in five to seven days. But an infection that gets into the bone could need weeks to months of treatment.
Once home, most horses need bandaging and stall rest for about two weeks--or at least until any sutures come out--and oral antibiotics for up to a month. In the meantime the owner should monitor the horse for lameness, heat, and other signs of returning infection. After the first two weeks the horse's regular veterinarian can evaluate the animal and decide whether to continue the antibiotics.
Fractures are no longer an automatic "game over." Some can be repaired, and some horses can even resume an athletic career following recovery. In adult horses, upper-limb fractures generally aren't repairable, but many lower-limb fractures are. For "a closed fracture--one with the skin intact--that's repairable, there's a decent prognosis," says Getman. "But if the fracture becomes open, the prognosis goes down dramatically," due to opportunity for infection. Thus, as soon as the veterinarian identifies a limb fracture, Getman recommends either bandaging or splinting the injured limb, so a closed fracture doesn't become an open one.
When the horse arrives at the hospital, Getman usually gives him a sedative and radiographs the limb. Then she'll discuss the horse's prognosis and "the economics of repair" with the owner.
Repair specifics depend on factors such as which bone fractured, how badly, and the horse's size. "Fractures that can be repaired with one or two screws generally have an excellent prognosis for life and even a good prognosis for the horse's going on to be athletic again," Getman says. "If a fracture needs at least one bone plate, or maybe two, it's more complicated--and we're probably looking just at saving the horse's life."
Horses with one- or two-screw fracture repairs usually spend only two or three days in the hospital "and tend to get remarkably comfortable soon after surgery," Getman says. Those with more involved repairs might need to stay a week to a month in the hospital, with continued IV antibiotics and pain medication.
In adult horses, fractures take about four months to heal: typically a minimum of two months of stall rest, with maybe a little hand-walking or hand-grazing; then another two months with more hand-walking and possibly turnout in a small paddock. For horses that veterinarians expect to return to soundness, count on at least four months before the horse can go back to being ridden, or to full turnout.
Other Surgical Prognoses
Countless other conditions aside from the most common listed above require surgical intervention. A brief rundown of their treatment and prognosis is as follows:
Cataract Surgery Veterinarians often remove cataracts (opacity in the lens or lens capsule that obscures vision) using a lens removal method called phacoemulsification if the horse does not have uveitis (inflammation of the uvea, or the cellular layer of the eye that contains blood vessels, the iris, ciliary body, and choroid) and has a healthy cornea and functional retina. Post-surgery, horses are treated with topical and oral medications for at least a month and should be kept out of bright light and have limited exercise. Because the lens was removed, these horses will essentially be far-sighted and might require lens implants to help them focus light properly. Veterinarians typically don't recommend these horses go on to rigorous riding careers due to their diminished vision.
Limb Amputation Amputations are no longer unfathomable in equine medicine. In a retrospective study of 34 partial limb amputation cases between 1986 and 2010, 22 (64.7%) survived at least six months. In surgical recovery, veterinarians keep horses in a sling and perform multiple cast changes under general anesthesia before the horse is outfitted with his permanent prosthesis several months later. Post-surgical problems are minimal if the horse's temperament is such that he tolerates the maintenance and extended recovery.
Laryngoplasty Horses with laryngeal hemiplegia (partial or complete paralysis of the larynx, also called roaring) often undergo surgical correction. While many horses return to work with improved performance, a research team from Cornell University reported that "the overall success rate of the various laryngoplasty techniques is modest at best, ranging from only 48-68%."
Arthroscopic Surgery Surgeons often remove separated bone fragments from horse's joints via arthroscope. Performing this procedure in the fetlock joint offers a good prognosis for a horse and can help prevent arthritis if performed early. After a rest period, many of these horses have gone on to have successful athletic careers post-surgery. Prognoses for the knee or other joints are less favorable in terms of future soundness. Fetlock joint arthrodesis is another pain-relieving surgical option that immobilizes the joint. While it makes the horse more comfortable, it will not restore athletic soundness. Complications might develop stemming from poor lower limb blood supply that prevents proper healing.
Tumor Removal Depending on tumor type, size, and location, many veterinarians will remove a lesion using laser surgery or surgery under general or epidural anesthesia. Generally, the biggest concern post-treatment is tumor regrowth.
Fielding's message for anyone taking a horse home after a surgical procedure is to "Watch carefully. Sometimes the little, early changes are what help us recognize that there's a problem," he says. "And it's a lot easier to make little adjustments before things get bad than to wait until they do get bad and then try to fix them. So if you've got a question, call."
About the Author
D.J. Carey Lyons is a lifelong resident of Chester County, Pa. She also has written for USDF Connection, Practical Horseman, Equine Images, and Dressage & CT.
POLL: Rehabbing the Injured Horse