Perineal Hernia
Perineal hernias occur due to the muscles around an animals perineal region (near the anus) becoming weak and separating. There are several muscles in this area that make up the “pelvic diaphragm” and normally these are meant to support the structures and organs in the pelvic cavity. When these muscles become weak, organs such as the rectum, bladder, prostate and intestine can move and protrude into the defect created.
Why do dogs get perineal hernias?
This condition is common in older male dogs which have not been desexed. The underlying cause and processes that lead to these hernias is not fully understood but there are many factors that have been linked to the development of the condition. Because it is so common in older undesexed male dogs, it is thought to have an underlying association with a hormone imbalance. There are also some breeds that are strongly predisposed to the condition, such as German Shepherds, Boxers, Corgis, Pekingese and Boston Terriers. This also suggests there may be a genetic component to the condition.
Hernias may also be exacerbated by any underlying disease or condition that causes dogs to strain a lot, such as constipation, urinary tract disease and prostate disease.
Signs of perineal hernia
Animals with perineal hernias will very commonly appear constipated and strain to poo. You may also notice a swelling on either or both sides of their anus. Animals may also show signs of straining to urinate or complete inability to urinate. Please note: inability to urinate is an emergency! If you are ever concerned that your dog is not able to urinate, he should be seen by a vet immediately.
How is a perineal hernia diagnosed?
Most simple perineal hernias can be diagnosed easily in the hospital. When performing a rectal examination, the hernia can be felt as the rectum develops a deviation or outpocketing as its wall falls into the hernial defect.
Sometimes a vet will also need to perform other tests, such as ultrasound or radiographs to check the location of other organs and to confirm whether they have become stuck in the hernia. Urinary tract obstruction can occur when the bladder falls into the hernial defect and this can cause significant systemic illness, so blood and urine testing may also be performed.
Why do we need to treat perineal hernias?
Herniated bladder and prostate
If perineal hernias are left untreated, the defect can continue to widen and there is an increasing risk over time that organs can become trapped in the defect.
If any organ becomes trapped in the hernia, the organ can become strangulated and its blood supply can be cut off. This can cause the organ tissue to die.
If the urinary bladder specifically gets trapped, this can lead to complete obstruction of the urinary tract, meaning the animal is not able to urinate at all.
Both of these scenarios can be life threatening; these patients are at high risk of developing severe systemic illness, including abnormal heart rhythms, sepsis (infection throughout the body) and even death, if not treated urgently.
How is a perineal hernia treated?
In most cases, surgery is recommended to treat perineal hernias. There are many different surgical techniques that can be involved in the treatment of these hernias, but most commonly treatment has two main steps:
Reduce the contents of the hernia – this commonly involves an incision into the abdomen to pull organs forward and secure them to the body wall so they cannot fall back into the hernia. This is most commonly performed on the large intestine (called colopexy) and urinary bladder (called cystopexy).
Repair the hernia – the aim of this is to reconstruct the pelvic diaphragm. There are many ways this can be done, but most involve suturing muscles in the area together or using a synthetic mesh to close the defect
It is also recommended to castrate (desex) patients while under the same anaesthetic, as this removes the source of excessive hormones that contribute to the hernia developing.
Post-operative care
Animals will usually be discharged within one or two days after their surgery, once they are comfortable. It is extremely important that patients wear their Elizabethan collar at all times to prevent them chewing at the sutures.
In the short term, some patients may require specific diets or stool softeners to make it more comfortable for them to defecate while the tissues nearby are healing.
If animals have any underlying diseases that may have contributed to the hernia developing, such as prostatic, urinary or gastrointestinal disease, it is important these continue to be managed long term to reduce the chances of the hernia recurring.