Hernias in Horses: The Different Types and Emergency Situations

A hernia, or hernias, occurs as the result of a defect in the body wall, which allows a portion of organ tissue to protrude through the tear, becoming displaced. In some cases, the hernia is not serious, and the tissue is even able to slide in and out of the gap, but other times it can become trapped, with potentially fatal consequences.

Horses of all ages and breeds can experience a hernia, of which there are many types and causes. It is important, therefore, to take swift action in diagnosing and treating any strange bulge that appears beneath your horse’s skin, and to watch for danger signs that could indicate an emergency.

While there are several kinds of hernias, based on their location in the body, some are more common than others – the most common being umbilical and inguinal hernias, which due to their proximity, affect the horse’s bowels in the form of errant loops of intestine.

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UMBILICAL HERNIAS

An umbilical hernia is located in the navel area of male and female foals, and can be present at birth, or develop shortly thereafter. Veterinarians speculate that trauma at the site, such as the mare tearing the umbilical cord abruptly, or the cord being cut too short, may interfere with proper healing of the umbilical stump, causing a defect in the body wall, leading to the formation of a hernia. It is not uncommon for an umbilical hernia, which appears as a bulge approximately three or four fingers wide near the navel, to resolve on its own. If it has not disappeared after six months, however, it should be surgically repaired.

As Dr. Judith Koenig, an associate professor of Large Animal Surgery at the Ontario Veterinary College, University of Guelph, advised, there is no good reason to put off having an umbilical hernia repaired. It is safer for your horse, not to mention your wallet, to have it fixed before it becomes an even bigger problem. “There is always the risk, if you have a defect in the body wall, that one day a piece of intestine will sneak its way in there, get trapped and swell,” said Koenig, “and then you would need colic surgery.

“When there is no intestine trapped it is a quick surgery – and it’s much cheaper. For example, to repair an umbilical hernia in a six- or eight-month-old foal, it would cost you $650 here at Guelph, whereas colic surgery would cost you $6,500. So, that makes a difference – you don’t want to wait for the bowel to become trapped.”

Koenig said it is a simple procedure to repair an umbilical hernia, in which the surgeon opens the hernia, replaces the tissue to its rightful place and sutures the body wall back together, closing the affected layers of the abdominal wall (made up of the peritoneum (lining), three muscle layers, subcutaneous tissue and skin). This is referred to as a herniorrhaphy. Recovery includes stall rest and hand-walking for about a month, and once healed, there are no lasting effects.

INGUINAL HERNIAS

Though one of the most common types of hernias, inguinal hernias only affect the groin area of male horses, and are believed to be caused by the strain of breeding as well as strenuous exercise.

There are two kinds of inguinal hernias – congenital and acquired – which can occur in colts and mature stallions alike.

Congenital inguinal hernias are present at birth, the potential for which begins in the womb. “When a male foal is in the uterus, the testicles descend from the abdomen into the scrotum, forming a narrow canal as the fetus grows,” said Koenig. In foals with inguinal hernias, the inguinal canal is wider than it should be, allowing a portion of the intestines to fall into the scrotum.

Koenig said this type of inguinal hernia often resolves on its own and can also be manually reduced by gently squeezing the scrotum daily, using a technique that your veterinarian will teach you, to push the tissue out of the scrotum and back into the abdomen. “Usually, if you do that every day for three or four months, the foal will outgrow the ring,” meaning that as the foal grows, the inguinal ring, which is formed by the inguinal canal, will not become any wider, thereby eliminating the problem. “You have up to four months before the inguinal space needs to be closed surgically.” This type of procedure is fairly easy and will cost about $850 at Guelph, according to Koenig.

Acquired inguinal hernias, on the other hand, are more serious. These can be either “indirect, where the intestine gets trapped through the inguinal canal into the scrotum, or direct, where the peritoneum (lining of the inguinal canal or beside it) tears, allowing the intestine to sneak into the scrotum,” said Koenig, who added that either type is an emergency, requiring immediate surgery. She noted that neither indirect nor directly acquired inguinal hernias are reducible (you can’t squeeze them back in) and that horses suffering from them will show signs of colic.

When tissue is trapped, regardless of the type of hernia, the surgery becomes more complicated. “In an emergency hernia operation,” said Koenig, “the surgeon must cut out the damaged section of bowel and make a new connection, which takes much longer to do.”

Once healed, horses with either type of inguinal hernia can go back to regular work; recovery times vary, however, depending on the severity, and whether or not any tissue was trapped. Specific post-operative instructions or discharge orders will be provided by the surgical team.

The latest advancement in hernia repair, according to Koenig, “is the laparoscopic placement of surgical mesh for inguinal hernias, where the mesh is placed from the inside.” This minimally invasive procedure “is considerably more expensive than routine repair, however.” Surgical mesh is another of the more recent innovations that has typically been used during surgery in cases where the defect or tear is quite large, in order to provide added strength and flexibility. The use of mesh implants can reduce tension at the suture closures, decrease post-operative pain and shorten the time spent in hospital.

TRAUMA-INDUCED HERNIAS

While not as common, it is possible for horses to sustain abdominal wall or body wall hernias as the result of trauma.

The most common type of abdominal wall hernia is an incisional abdominal wall hernia, which can occur, particularly following colic surgery, often due to an infection at the incision site or because the horse is exercised too soon. “This type of hernia is usually found right on the horse’s mid-line, the most dependant portion of the abdomen, which is the location where the incision for colic surgery is made,” said Koenig. “These incisions usually take three months minimum to gain back their full strength, and if people start to exercise the horse too early because they want to compete, for example, then part of the body wall can break and tissue can herniate through it.”

Koenig said incisional hernias are most likely to happen “when the sutures lose their strength, usually two to four weeks after surgery, and the body wall hasn’t had a chance to fully heal.” She also noted that some horses, unfortunately, cause an incisional hernia within the first 24-48 hours after surgery due to too much activity. She said the defect should be fixed, as there is a risk, particularly “if the horse is an athlete or a broodmare, of it ripping further.”

A body wall hernia can occur following a blunt force injury, such as a kick, for example. In this case, the injury causes a defect in the body wall, which allows tissue to escape, causing a mass to appear on the horse’s flank, which can get bigger over time.

Koenig said, “If you can push the hernia back in with your fingers, the intestine is not trapped, and it is likely not an emergency, but if you can’t push it back in, more urgent action may be required.” As with any type of hernia, you should have a vet out as soon as possible to examine your horse. Koenig warned that “if you notice additional swelling around the bulge, it is an indication that the bowel is trapped” and you are dealing with an emergency situation.

For body wall hernias that are deemed to be not of a serious nature, your vet may recommend the use of an abdominal belt or belly binder, which acts as a pressure wrap. The horse should wear the snugly-fitted belt daily for three to four months in the hopes of reducing the hernia. If it does not resolve in this manner, your vet will likely recommend a surgical fix.

Regarding whether or not abdominal wall or body wall hernias are painful, Koenig said, “When a hernia is acute (when it occurs) it can be painful because there is inflammation, but after six or eight weeks, the horse usually doesn’t feel any pain.” As soon as a portion of intestine falls into a gap, however, gets stuck and swells, she cautioned, the horse “becomes super colicky,” which is why vets often recommend surgical repair for hernias of this nature, as the defect is likely to get bigger over time. To repair them, “surgical mesh is sutured to the edges of the torn body wall to form a protective layer over the defect,”said Koenig. The elastic-like mesh is designed to stretch with movement and growth.

Following abdominal wall and body wall surgery, the horse must be on stall rest for one or two months and wear an abdominal belt for three to four months, and, Koenig said, it can take two to three months more before the horse heals fully and scar tissue forms. Not until then, should the horse resume its regular exercise routine.

Emergency Situations

In an emergency, where the intestine is trapped and begins to die off, bacteria leaks into the bloodstream releasing toxins into the horse’s system, and you have about four hours to get the hernia repaired before the blood supply is cut off. As the clock ticks, the following is taking place:

Additional swelling around the hernia may occur.
The horse’s heart rate goes up
The horse starts to go into shock
The trapped tissue begins to die off, then the intestine ruptures
The pain stops and the horse dies

Dolly the Herniated Pony

One day, I noticed that Dolly, my little Welsh-cross pony, had developed a swelling on her abdomen. I called in my vet and he initially diagnosed it as a hematoma or seroma caused by a kick from another horse, and said that it should heal on its own after a month or two. The problem was that it didn’t; about 18 months later, it developed into an abdominal wall hernia, and the mass began to get bigger. Otherwise, Dolly seemed comfortable and was not showing any signs of distress. I had no idea that an injury could lead to a hernia. I asked my vet to look into getting it repaired, and he suggested that I take her to Guelph. I decided to get the hernia fixed, but I was worried. I wondered, is she too old for the surgery at nearly 20? Would she survive? How much would it cost? Would I be foolish to spend the money?

The experience at Guelph was wonderful. Dr. Judith Koenig, who performed Dolly’s surgery, called me right after the surgery, and continued to keep in contact with me during Dolly’s eight-day stay. Because I live so far from the hospital, (in Bowmanville, Ontario) I was unable to visit, but she kept me well-informed of Dolly’s condition.

When we got Dolly home, her aftercare included a course of antibiotics, changing her dressing daily and wrapping her up in a pressure bandage for the first couple of days that made her resemble a sausage with feet, head and tail sticking out! After that initial period, she wore an abdominal belt, which made it much easier to change the dressing, which I did every day or two. The belt could be adjusted for additional swelling/shrinking of the abdomen. Two weeks later, my vet came to remove her stitches, after which the incision did open slightly, but healed well regardless.

Dolly was put on one-month stall rest, and I continued to change the bandage daily. She was hand-walked daily, then put into a small paddock for a few hours morning and night. She slowly started going outside for the whole day, and after three months of wearing the belt we were able to let her out “naked!”

As I write this, it has been a year since the surgery and the incision has healed beautifully. Looking at her in the field you can’t even tell she had a hernia. If I add everything up (all vet bills, surgery, before and aftercare, hernia belt, transporting to and from Guelph and taxes) the final bill was just under $4,000, but having the little pony in my field healthy and happy is priceless! ~ Lydia Keen