A perineal hernia is a protrusion into the pelvic floor, also known as the perineum. Such hernias are present in humans and are usually caused when part of an organ penetrates a cavity space surrounding it. Cats and dogs can also have perineal hernias.

The most common hernias are of the stomach, known as a hiatal hernia, and those involving the abdomen. Hernias are often congenital and inherited, and their likely development increases with age. In rare cases, they can be associated with diseases such as Marfan syndrome.

Perineal hernia can be caused by prostate and urinary diseases that weaken the pelvic floor. They are often also caused by surgery involving poor reconstruction of the pelvic floor. Such reconstruction is made more difficult if the surgery took place to remove the coccyx and/or the distal sacrum. Constipation and diarrhea can cause perineal hernia. An atrophied levator ani muscle or disease of the pudendal nerve can also lead to the condition.

There are a number of other elements that can cause a hernia around the pelvic floor. Fluids and fatty tissue are most likely to enter the cavity first. As the hole develops, parts of the intestine, rectum or bladder may enter the hernia. Early symptoms of a perineal hernia include vague feelings of discomfort and pressure around the rectum. A more developed perineal hernia will show itself as a lump on one or both sides of the rectum.

A prosthetic mesh is one method of treatment for perineal hernia, but it can lead to relatively high levels of recurrence due to poor anchoring of the mesh. Doctors have experimented with ways to fix the anchoring issue using orthopedics in addition to pig collagen grafts or human dermis grafts. Using a gluteus maximus muscle flap is another option for the mesh. By successfully anchoring the mesh, the fluids, fat tissue and organs are better contained and protected.

While a hernia might not cause pain or discomfort, it is possible for the organ area that has fallen into the cavity to get stuck. If this happens, the blood supply to that part of the organ can be cut off. Delaying treatment can also cause organ dysfunction and gangrene. If this happens, emergency surgery is required.