Perineal Hernia
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Article Written by Dr. Daniel A. Degner, Board-certified Veterinary Surgeon (DACVS)

Key Points

A perineal hernia is a condition that occurs in both dogs and cats in which there is an abnormal displacement of pelvic and/or abdominal organs (small intestine, rectum, prostate, bladder, or fat) into the region around the anus called the perineum

A perineal hernia is most successfully treated using the internal obturator muscle flap technique

Castration is always performed at the same time as the perineal hernia surgery so that the prostate will shrink, thus minimize straining during bowel movements

Success is highly dependant on the training and experience of the surgeon


  • The pelvic diaphragm is a set of muscles that are attached to each other and surround a hole called the anus
  • The pelvic diaphragm consists of the levator ani, coccygeus and external anal sphincter muscles
  • This diaphragm is a dam that keeps the internal organs such as bowel, prostate and bladder in place.

Perineal hernia - definition and clinical signs

  • A perineal hernia is a condition that occurs in both dogs and cats in which there is an abnormal displacement of pelvic and/or abdominal organs (small intestine, rectum, prostate, bladder, or fat) into the region around the anus called the perineum.
  • This condition occurs secondary to a weakening of the muscles, which form the pelvic diaphragm.
  • Signs of this problem include straining to urinate or have bowel movements, constipation, and swelling around the anal region.


Causes of Perineal Hernias

  • The reasons for development of this disease are not completely understood.
  • The vast majority of cases occur in intact male dogs that are middle-aged or geriatric. The most probable cause is prostate enlargement due to the animal not being neutered.  Straining due to an enlarged prostate weakens the pelvic diaphragm.
  • Other theorized causes of perineal hernias include anatomic factors, hormonal imbalances, damage to the nerves of the pelvic diaphragm, and straining due rectal disease.



  • The condition is easily diagnosed by digital rectal palpation during a physical examination. 
  • X-rays or ultrasound may be required to further define the hernia.



  • A perineal hernia does not require emergency surgery, however, if the bladder is located in the hernia, emergency treatment may be needed, as the pet may not be able to urinate.
  • Prior to surgery an epidural is done to relieve pain and minimize straining after surgery.
  • A perineal hernia is most successfully treated using the internal obturator muscle flap technique. This surgical procedure creates a new pelvic diaphragm with the transposed muscle flap. The internal oburator muscle is an external rotator muscle of the hip and can be safely sacrificed with no ill effect to use of the limb.
  • Other procedures that may be performed include the following:
    • Colopexy, a procedure in which the colon is tacked to the left body wall and helps to prevent pressure on the repaired hernia
    • Cystopexy, a procedure in which the bladder it tacked to the right body wall.
    • Ductus deferensopexy, a procedure in which the ductus deferens (a cord that goes to the testicle) is attached to the body wall to help prevent the prostate from herniating
    • These procedures are never used as a primary treatment, rather are always used in conjunction with the obturator flap procedure.
  • Castration is always performed at the same time as the perineal hernia surgery so that the prostate will shrink, thus minimize straining during bowel movements.
  • Below is the hind end of a dog that has a severe perineal hernia (Fig 1).  When the hernia is opened, small intestine, bladder and prostate were found to be in the hernial sac (Fig 2).  These organs were placed back into the abdomen and the hernia was repaired.

       Fig 1      

       Fig 2


Convalescence period

  • By 10 to 14 days after the surgery most of the swelling at the level of the surgery will have resolved.
  • Some straining during bowel movements is expected and usually will abate in 7 days.
  • By 6 to 8 weeks after surgery, complete healing has taken place.



  • Surgery is successful 80% of the time.
  • Success is highly dependant on the training and experience of the surgeon.  In my opinion this type of case usually should be referred to a specialist for surgery.
  • Failure of the surgical procedure results in recurrence of the hernia. A second procedure would be needed to repair the hernia again.


Potential complications

  • Infection
  • Straining to have a bowel movement, can be due to irritation and inflammation of the rectum, which is adjacent to the surgical site. Adding Metamucil to your pet’s food after the surgery will soften the stools so that bowel movements will occur more easily.
  • Fecal incontinence is more common if your pet has hernias on the left and right sides. The cause of the incontinence is due to weakening of the valve of the anus. With this type of problem, stool may accidentally fall out of the anus when the pet is exited, or while barking. In most cases, this is a temporary problem.
  • Urinary incontinence is usually not seen unless the bladder has been chronically located in the hernia.  This is due to stretching of the nerves of the bladder and usually resolves with time.
  • Anesthetic death is an uncommon complication.


Postop care

  • Stool softeners help to minimize the straining and constipation.
  • If your pet has a significant amount of straining a medication called Proctofoam will be prescribed; it has a local anesthetic and a steroid in it.  It should only be needed for a couple of days.
  • Pain medication will be prescribed to minimize discomfort.
  • Licking the incision can be prevented by using an Elizabethan collar.
  • Sutures do not need to be removed as these usually are internal and will dissolve with time.
  • During the first 3 weeks after surgery, activity is restricted to short leash walks outside. Running, jumping, or rough play is forbidden. Gradually increasing the activity, following the third week after surgery, allows for a safe recovery.

Frequently Asked Questions After Surgery

When should my dog have the first bowel movement after surgery?

  • Many dogs will not have a bowel movement for the first 4 to 5 days after surgery
  • Reasons that a dog will not have regular bowel movements after surgery include:
    • The dog has been fasted prior to surgery
    • Dogs do not eat well during the hospital stay
    • They frequently do not eat well when they go home
    • They are fed highly digestible food that produces little stool
    • Pain medication that contain narcotics (such as morphine, fentanyl patches, and tramadol) can be constipating
  • If a pet does not have a bowel movement on the 5th day of being home, a stool softener such as metamucil can be fed
    • Dose of metamucil is 1 tsp per 25 Kg mixed in with each meal (canned dog food); feed immediately after mixing, as the metamucil will gel the food and may make it less palatable

My pet had surgery and will not eat.  What can be done?

  • Dogs
    • Most pets will not eat their regular dog food after surgery, especially if it is kibble.
    • Offer a cooked diet having a 1:1 ratio of a protein source and carbohydrate source.  The protein source can be any meat (example: chicken breast, turkey breast, lean hamburger) that is low in fat and should be cooked (drain off all fat after the meat has been cooked).   The carbohydrate can be pasta, potato or white rice.
    • Try canned dog food; to enhance the flavor sprinkle a very small amount of garlic powder or chicken or beef broth (Chicken-in-a- MugTM or Beef-in-a-MugTM products)
    • Try Gerber strained meats for babies such as the chicken, beef, turkey, or veal
    • Try Hill's A/D diet available at most veterinary hospitals
    • Hand feeding: place a small amount of food in the mouth so that your dog gets the flavor
    • Warm the food slightly in a microwave, as the food will be more aromatic; stir the food before feeding and test the temperature on the bottom side of your wrist; it should only be luke warm.
    • Remember that most pets will not eat the first day or two after they get home from surgery
  • Cats
    • Offer smelly foods that contain fish such as tuna or smelly cat foods
    • Try Gerber strained meats for babies such as the chicken, beef, turkey or veal
    • Hand feeding:  with your finger place a small amount of food on the roof of your cat's mouth; use a syringe to get soft food into the mouth
    • Warm the food slightly in a microwave as the food will be more aromatic; remember to stir the food before feeding and test the temperature; it should be only luke-warm
    • Some cats will only eat dry food, try kibble if your cat normally has been fed that food
    • Petting and stroking your cat frequently will help to stimulate appetite
    • Remember that most pets will not eat the first day or two after they get home from surgery
    • Appetite stimulants such as cyproheptadine may be helpful
    • If your cat refuses to eat anything for 7 days a stomach tube or nasogastric tube should be placed to provide nutrition so that a serious liver problem (hepatic lipidosis) does not develop

My pet is vomiting.  What can be done?

  • The first thing for you to discern is whether your pet is vomiting or regurgitating.  Both will result in fluid or food being brought up.  Vomiting always will have heaving or retching of the abdomen prior to expulsion of the vomitus.  Regurgitation is not associated with heaving and the pet usually just opens the mouth and fluid or food will be expelled.  Usually the regurgited material will be clear or brown colored fluid. 
  • Next is to identify the cause of the vomiting or regurgitation.
  • Causes and treatment of vomiting after surgery
    • When some pets return home after a stay in the hospital they may drink excessive amounts of water at one time and then vomit; if this appears to be the case, the water should be limited to frequent smaller amounts.
    • Medications such as antibiotics, narcotics or nonsteroidal anti-inflammatory medication commonly cause vomiting after surgery.  In order to see which medication is causing the problem, the administration of each drug should be separated 2 hours apart.  Usually the pet will vomit or appear nauseated (drooling and sick look) within 1 hour of administration of the medication that they are sensitive to.  The antibiotic in some cases may be changed to a different one, or may be discontinued. 
    • Stomach upset from anesthesia is a potential cause of vomiting and will pass within a couple of days. 
    • An uncommon cause of vomiting after surgery is internal organ failure.  Blood testing will confirm this problem. For this reason vomiting should not be ignored if it persists for more than 24 hours.
    • If your pet had surgery of the bowels or stomach, vomiting is always a concern, as it may indicate that infection of the abdominal cavity, called peritonitis, is present.  Do not ignore this sign.
    • Symptomatic treatment of vomiting involves withholding food for 12 to 24 hours, then introducing small amounts of bland food such as rice and lean cooked hamburger, if your pet does not vomit after that then gradually wean him/her back onto the regular diet after 3 days.  In order to decrease the acidity of the stomach, Pepcid AC 0.5 mg/kg can be given by mouth twice daily for 5 days.  Metoclopramide and Cerenia are good anti-vomiting medications for dogs and cats.  You should always consult a veterinary healthcare professional before administering medication.
  • Causes and treatment of regurgitation after surgery
    • The most common cause of regurgitation is reflux of acid from the stomach into the esophagus while your pet is under anesthesia.  Acidic fluid from the stomach can cause a chemical burn of the esophagus and result in a bad case of heart burn, called esophagitis.  This results in poor motility of the esophagus, therefore water and food will accumulate in this structure.  In most cases, esphagitis is self-eliminating and will resolve within two or three days. 
    • If the esophagitis is severe the esophagus may develop one or more strictures.  A stricture is a narrowing or stenosis of the esophagus and does not allow passage of food down the esophagus, in regurgitation that lasts longer than one week.  This problem should be brought to the attention of your pet's doctor within the first two weeks so that it can be treated by ballooning the stricture (minimally invasive procedure, as it is done with the aide of an endoscope).  If an esophageal stricture is chronic surgery is needed.
    • Symptomatic treatment of regurgitation caused by esophagitis includes feeding bland food, and administering a coating agent (sucralfate) and an acid blocker (omeprazole or other).  Consult a veterinary health care professional if the regurgitation continues for more than a couple of days.

How do I know that my dog is in pain following surgery?

  • Signs of pain include
    • crying
    • biting if you get near the surgical site
    • grimacing (lips are pulled back and the the dog looks anxious)
    • tragic facial expression
    • panting
    • restlessness and unable to sleep; pacing
    • if abdominal surgery was done the pet will not lie down on the incision, or will continually sit up in spite of appearing very tired
    • the worst pain will be for the first 2 to 3 days after surgery

What can I do to control my dog's pain?

  • Narcotic medications that control pain: tramadol, butorphanol, Duragesic (fentanyl patch)
  • Anti-inflammatories used to control pain: Deramaxx, Rimadyl, Previcox, or Etogesic
  • If an orthopedic surgery has been done cold packing the surgical site may be helpful
    • A cold pack may be a pack of frozen peas, crushed ice in a Ziploc bag, or a cold gel pack; place a thin barrier between the skin and the cold pack.  An alternative to a cold pack is to freeze water in a styrofoam cup; after frozen cut the bottom of the styrofoam cup out. Cool the surgical site around the incision by rubbing the exposed ice directly on the skin in a circular pattern.  Cooling the surgical site helps to numb the area.

How do I know that my cat is in pain following surgery?

  • Pain is more difficult to assess in cats versus dogs, as signs can be more subtle and they usually do not vocalize when in pain
  • Signs of pain in a cat include the following:
    • biting if you get near the surgical site
    • growling or deep cry
    • not wanting to eat
    • hiding and not wanting to be near owner (remember that this could also be caused by the cat just being upset about leaving home and coming back)

What can be done for pain at home for my cat?

  • Pain medication such as buprenorphine or a Duragesic (fentanyl) patch
  • Tylenol will kill a cat as they lack abundant glutathione enzyme in the liver
  • Anti-inflammatories can be used, but the dose is much less than dogs

Is it okay for my pet to lick the incision?

  • If a dog licks the incision, the healing process may be delayed.
  • Licking can remove stitches and cause the incision to open
  • Licking can become a severe habit that is difficult to break
  • Licking can cause infection as the mouth has many bacteria
  • Dogs will frequently lick the incision when the owner is not watching such as at night time; if the skin looks red or excoriated the most common cause is from licking.
  • To stop your pet from licking the following can be tried:
    • Elizabethan collar can be placed on the neck; this will not help stop your pet from scratching at the region
    • Cervical collar (bite not collar) is a less awkward device and can be effective at stopping a pet from licking the surgical site
    • A tee shirt can be used to cover an incision on the chest or front part of the abdomen; gather the waist of the shirt up over the dog's back and wrap an elastic band around this part of the shirt.
    • A bandage or sock can be used to cover an incision on a limb; fasten the top of the sock to the dog's limb with tape.
    • Bitter apple can be applied around the incision; many dogs will continue to lick  after application of this topical
    • Bitter Apple and Liquid HeetTM (obtain this from a is used for sore muscles) mixed in a 2:1 ratio can be applied around the skin incision
    • Antipsychotic medication in some cases is needed

Board-certification by the American College of Veterinary Surgeons

What does it mean?

  • Four years of advanced training in surgery beyond the Doctor of Veterinary Medicine Degree

  • Experience in the development of new surgical treatments

  • Rigorous examination by the American College of Veterinary Surgeons to ensure competency in advanced surgical techniques

  • Assurance that a veterinarian is a surgical specialist

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