Hernias can range from small, self-resolving nuisances to life-threatening emergencies that require surgery to correct.
From harmless nuisance to life-threatening emergencies, here are some real-life examples of intestinal escape
Imagine up to 100 feet of intestines delicately stuffed into a compact and fairly rigid compartment (aka, the abdominal cavity). Now imagine a sudden burst of pressure applied to that compartment or a small tear developing somewhere in the body wall. Where are those intestines to go? In most cases, nowhere. But in some cases they can pop through the body wall, diaphragm, or even through a pre-existing hole. And give the intestines an inch, and they’ll take the proverbial mile.
“A hernia is simply the protrusion of an organ or tissue through an abnormal opening,” explains Claude Ragle, Dipl. ACVS, ABVP (Equine Practice), associate professor in equine surgery at Washington State University’s College of Veterinary Medicine. “The intestines are among the most common tissues to herniate.”
In this article we will describe some classic hernia scenarios veterinarians encounter, along with more unusual cases. Our sources will help explain how/why these hernias occur, how to treat them, and the prognosis associated with each.
Case 1: Filly With a Bulging Bellybutton
The owners of a 6-week-old filly noticed a 5-cm nonpainful soft swelling near her umbilicus (a neonate’s bellybutton). They called their veterinarian and reported that the filly had no known medical issues and that both her gestation and parturition were normal. The owners reported no change in the foal’s appetite or behavior or any other abnormalities.
The veterinarian’s diagnosis: an umbilical hernia.
These are the most common type of hernia identified in horses, occurring when the intestines protrude through a defect in the body wall near the bellybutton. It is important to distinguish such hernias from umbilical infections, usually via ultrasonography. Treatment for umbilical hernias can range from conservative to surgical. Many small umbilical hernias resolve with daily manual or digital reduction (i.e., coaxing the intestines back into the abdominal cavity with your fingers). Using this approach, hernias no longer than the width of three to four fingers typically resolve by 12-24 months of age.
According to the American Association of Equine Practitioners (AAEP), smaller hernias that do not heal spontaneously despite digital reduction and larger hernias measuring more than 10-12 cm in length often require surgery. Veterinarians use two surgical approaches: open and closed.
With an open reduction, the surgeon opens and evaluates both the hernial sac and abdominal cavity. He or she then cuts out the damaged part of the sac and repairs the body wall defect. In contrast, the closed technique does not require entering the abdominal cavity. Instead, the veterinarian incises the skin over the hernia without opening the sac and examining its contents. This means the surgeon never enters the abdominal cavity itself, which decreases the horse’s chances of infection.
“I prefer the open approach,” Ragle says. “The closed technique requires the needle (used to stitch the body wall together and reduce the hernia) to be placed blindly and unguarded and leaves redundant tissue behind. Those are the trade-offs for marginalizing asepsis (infection).”
Some practitioners take a different approach to managing umbilical hernias in foals. For example, Mark Georgetti, BVSc, MACVSc, MRCVS, a partner at Three Counties Equine Hospital, in Gloucestershire, U.K., described at the 2012 British Equine Veterinary Association Congress how veterinarians can manage one- to three-finger (2- to 8-cm) hernias by placing rubber Elastrator rings (which cut off the blood supply to that area) around the hernial sack. He reported that foals do not usually display discomfort after the veterinarian applies the ring, and after two to three weeks, the hernial sack sloughs and should heal uneventfully.
Despite Georgetti’s and others’ success using this approach, the AAEP warns against using elastics or clamps to treat hernias because of the risk of the intestines becoming trapped within the correction device, causing colic and possibly death.
“I would only use those techniques (elastics or clamps) in circumstances were I did not have access to the resources—equipment, training, personnel, finances—needed to do an aseptic (sterile) primary closure,” Ragle says.
Most foals with umbilical hernias, regardless of size or age, do not show any signs other than the obvious protrusion. But if a herniated foal becomes colicky, it could be because the intestines have become trapped inside the hernia, causing an intestinal blockage. Immediate veterinary attention is warranted in such cases.
Case 2: Something Askew With a Stallion’s Scrotum
A recently gelded 3-year-old Thoroughbred was referred to a surgical facility after his small intestines protruded through the inguinal canal and were clearly visible through an incision the treating veterinarian had made in the scrotum.
The veterinarian’s diagnosis: a scrotal hernia (a type of inguinal hernia).
Inguinal hernias occur when intestines burst through one of the small canals in a horse’s pelvic region, such as the inguinal canal (which extends from the deep inguinal ring in the abdomen to the superficial inguinal ring near the groin’s subcutaneous tissues and lies flat between the internal and external abdominal muscles). These types of hernias, including scrotal hernias after castration, are the second most common type of hernia in horses, says Georgetti. A case report published in the November 2013 edition of Equine Veterinary Education highlighted this potential post-castration complication, which reportedly occurs in approximately 0.2-4.8% of stallions undergoing the procedure.
Fabio Torre, DVM, Dipl. ECVS, from Italy’s Clinica Equina Bagnarola, lead author of that report, adds, “Evisceration (protrusion of intestines through the surgical site) is probably one of the most life-threatening complications following castration and requires emergency surgical management to either replace or resect the intestines if they are damaged or unhealthy and ensure they do not herniate again.”
Torre was the first to report a different type of inguinal hernia that is fairly common in people.
“In the horse described in my case report, the intestinal contents actually herniated through the femoral ring in the femoral canal,” says Torre. “That ring is where the femoral vessels pass from the pelvis to the limb.”
Not all inguinal hernias, however, result in intestines invading the scrotum; for instance, they can remain in the inguinal canal without popping through the abdominal wall. Even mares and neonates can develop inguinal hernias. When horses with such hernias develop signs of colic, veterinarians recommend immediate referral for surgery.
A group of Spanish veterinary surgeons have described several approaches veterinarians can use, ranging from conservative to surgical, to resolve inguinal/scrotal hernias:
- Manual reduction of scrotal hernias with external massage to the area, as described with umbilical hernias in foals.
- Surgery involving an incision either directly over the inguinal ring or the abdominal cavity, enabling the veterinarian to assess the trapped intestine and pull it back into the abdomen.
- Minimally invasive laparoscopic surgery, which involves using a small fiber-optic tube with a camera to perform procedures through a small incision rather than a standard larger surgical incision.
The primary drawbacks to the manual reduction method, say the surgeons, are that it apparently involves “intense massage” to the scrotal area, and that massage does not provide the veterinarians with any information regarding the health of the trapped intestinal tract.
Researchers have reported good prognoses and high rates of survival following both the standard surgery (Medoza et al., 2010) and standing laparscopy (Wilderjans et al., 2012).
Ragle says laparoscopy coupled with a barbed suture (a type of knotless surgical suture that locks to the tissue, commonly used in human cosmetic surgery) “proved to be safe, effective, and eliminated the need to suture the inguinal ring and tie knots deep in the horse’s body,” when treating inguinal hernias. However, he has only performed this technique in one case so far because the barbed suture is a fairly new product. “This technique is most applicable for use in the rare case of inguinal hernia of the gelding and in foals. In stallions, Dr. Wilderjans’ technique is recommended,” comments Ragle.
“Reduction of wound infection rates will reduce incisional hernia incidence.”
Dr. Mark Georgetti
Case 3: Infected Incision, Intestinal Escape
A 13-year-old Quarter Horse gelding developed colic and was referred to the local surgical facility. The horse underwent abdominal surgery, during which the surgeon resected 15 feet of small intestine. Postoperatively, the horse developed an infection of the surgical incision and a section of the remaining small intestines herniated through part of the incision.
The veterinarian’s diagnosis: a postoperative abdominal/incisional hernia.
There is approximately an “8% ventral hernia incidence following a single laparotomy,” a procedure involving a large incision through the abdominal wall, says Georgetti. “Reduction of wound infection rates will reduce incisional hernia incidence.”
In other words, an incision that heals without infection eliminates an opening for a hernia to occur.
Alternatively, some abdominal hernias occur secondary to trauma. Regardless, veterinarians can manage horses with abdominal hernias conservatively by treating any infection present and using a “hernia belt.” If the veterinarian deems surgery necessary, he or she can take a number of approaches, including full abdominal surgery to repair the hernia or laparoscopy. Some surgeons routinely use a sterile polypropylene mesh to help support the body wall and prevent additional herniations.
Not all surgeons, however, are convinced that using a mesh improves a horse’s outcome. In 2011, Canaan Whitfield, DVM, Dipl. ACVS, a graduate research assistant at Texas A&M University, and colleagues conducted a study to compare horses with abdominal wall hernias that were repaired without mesh to a small number of horses with similarly sized hernias repaired with mesh. Their results indicated no difference in cosmetic outcome between the two groups, but the mesh was associated with longer hospitalization after surgery and more postoperative complications. The authors did note that with very large hernias a mesh might be the only option to support the body wall.
Case 4: Continuous Colic
A 20-year-old Quarter Horse mare developed colic that waxed and waned over several weeks. Her veterinarian performed an abdominal and thoracic (chest) ultrasound examination and X ray following complete physical and rectal examinations. Due to the continued unresolved colic, the mare was taken to surgery and the surgeons found the small intestines herniated through a tear (also called a “rent”) in the diaphragm, meaning the intestines had gained abnormal access to the chest cavity.
The veterinarian’s diagnosis: a diaphragmatic hernia.
Although quite uncommon, diaphragmatic hernias can and do occur. Unfortunately, they are associated with a poor prognosis. In a 2006 study Romero and Rodgerson reviewed the medical records of horses treated at Hagyard Equine Medical Institute from January 2001 to June 2006 and found 31 cases of diaphragmatic rents with herniation. Of those, 25 were adults and six were foals. Twenty-five horses were taken to surgery, and 17 of those horses had diaphragmatic tears on the left side.
The study authors reported that the prognosis for a horse presenting for surgical correction of a diaphragmatic hernia was poor at 23%, but they predicted that future advances in abdominal surgery, along with improved prognoses for horses experiencing intestinal ischemia (loss of blood flow to the intestine), would ultimately improve surgical success rates. They noted that additional studies in this area would be warranted.
Hernias can range from small, self-resolving nuisances to life-threatening emergencies. Many treatment options exist, and each poses pros and cons. Always discuss your options and concerns with your veterinarian for the best cosmetic and functional outcome.
About the Author
Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.
POLL: Colic Surgery