Umbilical and inguinal hernias

There are several types of hernia (also known as a rupture) seen in the dog and the causes vary between the different types. Some hernias can be minor, but in certain circumstances they can be very serious and often require surgical treatment.

©University of Cambridge

A hernia is a swelling caused by structures from the abdomen bulging out through the muscle wall. The structures may escape by stretching a natural opening such as in an umbilical hernia, or come through a defect in the muscle wall that has developed due to old-age or trauma. The swelling may appear as a lump under the skin on the abdomen (umbilical, inguinal) or beside the anus (perineal). Typically, the swelling contains some fatty tissue but, in some cases, abdominal organs (most commonly sections of bowel) could be present.

Sometimes hernias form between the deeper muscle layers so the swelling is not obvious when looking from the outside. These may go unrecognized until your dog becomes unwell due to entrapment of a vital structure. Signs could include bringing up food/regurgitating for hiatal hernias or rapid or difficulty breathing with diaphragmatic hernias.

An umbilical hernia is a soft non-painful swelling over the umbilicus (belly button). This type of hernia is present from birth (congenital) in most cases. In the womb the fetus receives nutrition through the umbilical cord and, soon after birth, the umbilical cord is cut and starts to shrivel away on the outside. Inside the body the openings in the muscles of the body wall should also start to close. However, sometimes this opening doesn’t close as it should. Sometimes the hernia is very small but umbilical hernias can be large and may also occur along with other defects of development within the midline (midline fusion defects).

If umbilical hernias are very small you may be able to feel a small dent in the midline where the belly button is. It may be that no treatment is necessary. However, hernias may increase in size and your veterinarian may recommend surgery to close the defect. Often an umbilical hernia is repaired at the same time as general anesthesia for neutering.

Incisional hernia

An incisional hernia is a swelling that occurs at the site of surgery because the muscle layer of the abdominal wall has not completely healed. Sometimes this is due to insufficient rest after the operation but may also occur if your dog’s ability to heal is compromised. If a wound opens up again after abdominal surgery there can be very serious consequences for your pet

An inguinal hernia is nonpainful swelling in the groin (inguinal region), and can occur on one or both sides. The inguinal ring is a small natural opening designed to allow blood vessels to travel to the back leg (and to the testicles in the male). It is normally a slit like opening so nothing can pass through other than the vessels. However, in some dogs it is larger in which case internal tissues may pass through the opening. Inguinal hernias can be congenital (present from birth) or may develop later in life – more commonly in overweight, entire female dogs due to the influence of hormones. In the male dog the hernia can extend into the scrotum and castration is recommended during surgery to reduce the risk of recurrence.

If your dog has a hernia you may notice a soft, doughy swelling or a mass which is not painful. There are typically no other signs with umbilical and inguinal hernias. However, if a piece of intestine has passed into the hernia and become trapped (strangulated) more serious signs can develop. Your dog may be very unwell and vomiting. Strangulated hernias are often painful and the skin surrounding them may be red to blue-black in color.

The characteristic soft and non-painful swelling in a classic location may make your veterinarian suspect your dog may have a hernia. Your veterinarian may be able to distinguish a hernia from other forms of swellings, such as an abscess or a tumor by the appearance and feel of the mass when they examine your dog. They may be able to gently push the swelling back inside the abdomen and feel the hole it came through. Further tests such as x-rays of the abdomen or possibly an ultrasound may be necessary to confirm the diagnosis following the assessment. In some circumstances a Computed Tomography (CT) scan may be chosen if it is available and additional information is considered beneficial.

Your veterinarian may decide not to treat a very small hernia in the umbilical region but, if so, these must be regularly monitored by owner and veterinarian to ensure it is not getting larger.

Surgical treatment of hernias is frequently recommended due to the risk of progression and serious complications. Under a general anesthetic the area of the swelling is opened to allow the contents to be pushed back into the abdomen. The opening is then closed; either completely, if that is how the anatomy is meant to be, or almost completely, if vessels need to travel through the opening.

If a non-painful soft hernia becomes painful and firmer, you must seek urgent veterinary attention for your dog. The development of pain and firmness suggests inflammation and raises the suspicion that a serious complication has occurred. An internal organ may have entered the hernia and become twisted – this is particularly serious if a portion of bowel is involved. A twist in the bowel can cut off the blood supply and the section of bowel may start to die which can result in a life threatening infection.

In many cases there is nothing you can do to prevent this problem arising. However, in females they may occur after pregnancy. Umbilical and inguinal hernias may be present from birth and affected dogs (and their parents) should not be bred from as the condition may be inherited.

There is a risk with any surgery of bleeding, wound infection and wound breakdown. With a hernia there is also the risk of recurrence. It is important to monitor for signs of bleeding, swelling of the area around the wound, recurrence of swelling beneath the wound and wound discharge. If you see any of these signs please speak to your veterinary surgeon for advice.

The wound itself is left open to the air after surgery and should be kept clean and dry. If you are concerned that the wound is dirty contact your veterinarian before bathing the wound as the risk of infection is higher if the wound is wet. Your dog, and other pets, should be prevented from interfering with the wound. You must use a buster collar, post-op coat or T-Shirt to prevent interference and keep other pets away from your dog when you are not supervising interactions.

After surgery you should watch your dog closely to see that they are showing normal behaviours such as passing urine and feces normally and have a good appetite.

Your dog’s exercise should be restricted during the recovery phase, until your veterinarian has completed a post-operative check and is happy with the healing. Your dog must remain on the lead at all times for the first 10 days, even when taken to the garden for toilet purposes. Your veterinarian will give you specific instructions regarding the return to a normal level of exercise; typically on lead exercise must continue for a further 4 weeks with a gradual increase in length of walk each day.