Perineal hernias are relatively uncommon problems in most pet dogs. When they do occur, they usually occur in unneutered male dogs. Fortunately, surgical repair is an effective treatment for this pelvic issue.
What Is a Perineal Hernia in Dogs?
A perineal hernia occurs when the pelvic diaphragm becomes weakened or fails completely. Under normal conditions, the pelvic diaphragm is a muscular "wall" that supports the rectal area and keeps the contents of the abdomen separate from the rectum. Weakness or failure of the pelvic diaphragm may cause parts of the intestines and/or bladder to slip past the pelvic diaphragm and displace contents of the rectal area.
Signs of Perineal Hernias in Dogs
The first sign of a perineal hernia is typically swelling on one or both sides of the dog's anal opening. Other signs may or may not appear, such as constipation, and problems with defecation. Perineal hernias may involve the dog's bladder, leading to urinary complications like incontinence and difficulty urinating.
Veterinarians typically diagnose perineal hernias based on rectal exam findings. Radiographs may be necessary to see how the bladder and intestines are affected by the hernia.
Causes of Perineal Hernias
The exact cause of perineal hernias is unknown. Puppies may be born with congenital or inherited perineal hernias, but most perineal hernias tend to occur in middle-aged to senior dogs. Unneutered males are more commonly affected than neutered males, so veterinarians suspect hormones may play a role in the development of perineal hernias. Female dogs can develop perineal hernias, but they are uncommon.
Surgery is the only curative treatment option for a perineal hernia. Severe perineal hernias may require emergency surgery. Minor hernias may be treated conservatively at first in order to manage symptoms until surgery can be performed. Conservative treatment involves feeding high-fiber, wet food and administering stool softeners. A veterinarian may periodically need to remove impacted stool manually. Perineal hernias become worse over time and eventually need surgical repair.
Surgical repair of a hernia is called herniorrhaphy. There are a few different surgical methods for repairing perineal hernias in dogs, but the ultimate goal is to repair the pelvic diaphragm. In general, surgery involves returning the contents of the abdominal cavity to the abdomen and repairing or replacing the pelvic diaphragm. If the bladder is trapped in the hernia, a urinary catheter will be placed in order to empty the bladder first. The bladder and colon may be sutured to the abdominal wall to prevent a recurrence. Prosthetic implants are sometimes used as part of the repair process. Male dogs are typically neutered during the procedure in order to shrink the prostate and reduce the chance of recurrence.
Most dogs recover well following surgery for a perineal hernia, but complications can occur. Potential complications include infections and rectal prolapse, fecal incontinence, nerve damage, and rectal fistula (a hole or tunnel that forms from the rectum to a nearby part of the body. Fortunately, serious complications are rare. Most dogs will fully recover and go on to live normal lives.
Antibiotics are typically administered postoperatively in order to prevent infection. Most dogs will need to be fed a high-fiber diet and take stool softeners during recovery. Keep the incision clean and dry and do not allow your dog to lick or chew the area. An e-collar (Elizabethan collar or "cone") will be necessary while your dog is healing because dogs simply cannot resist the urge to lick or chew the surgical site.
Be sure to follow your vet's recommendations for postoperative care. Contact your veterinarian immediately if your dog is not recovering as expected.
How to Prevent Perineal Hernias
There is no sure way to prevent perineal hernias in dogs. Selective breeding may decrease the likelihood of perineal hernias in offspring; dogs with a history of perineal hernias should not be used for breeding.
Early detection may simplify treatment and make surgery more successful, so be sure to contact your veterinarian if you notice swelling near the rectum, abnormal urination/defecation, or any other signs of illness.
Ragni, Rosa Angela, and Alasdair Hotston Moore. “Perineal Hernia.” Companion Animal, vol. 16, no. 8, 2011, pp. 21–29.
Bernardé, A., et al. “Surgical Findings and Clinical Outcome after Bilateral Repair of Apparently Unilateral Perineal Hernias in Dogs: Bilateral Surgery for Unilateral Perineal Hernias.” The Journal of Small Animal Practice, vol. 59, no. 12, 2018, pp. 734–741